Spring4 MVC+Hibernate4 Many-to-many连接表+MySQL+Maven实例

这篇文章显示 Hibernate 的多对多实例，在 Spring%uA0MVC CRUD%uA0Web应用程序中连接表。我们将同时讨论管理多对多关系在视图和后端。%uA0我们将使用应用程序的Web界面创建，更新，删除和查询。

本教程是利用 Spring 的 org.springframework.core.convert.converter.Converter 接口，它帮助我们在项目的数据库中实现实体的映射标识。

完整的示例的说明介绍如下。

使用以下技术：

Spring 4.1.7.RELEASE
Hibernate Core 4.3.10.Final
validation-api 1.1.0.Final
hibernate-validator 5.1.3.Final
MySQL Server 5.6
Maven 3
JDK 1.7
Tomcat 8.0.21
Eclipse JUNO Service Release 2

现在，让我们开始！

步骤1.创建模式用于连接多对多表关联

APP_USER%uA0:包含用户。一个用户可以有多个配置[USER，ADMIN，DBA]。

USER_PROFILE%uA0:%uA0包含用户配置文件。配置文件可以链接到多个用户。

APP_USER_USER_PROFILE%uA0:%uA0这是一个连接表连接APP_USER＆USER_PROFILE中的多对多关系。

出于演示的目的，我们在这里只讨论许多对多的单向[用户到用户信息]设置。

create table APP_USER (
   id BIGINT NOT NULL AUTO_INCREMENT,
   sso_id VARCHAR(30) NOT NULL,
   password VARCHAR(100) NOT NULL,
   first_name VARCHAR(30) NOT NULL,
   last_name  VARCHAR(30) NOT NULL,
   email VARCHAR(30) NOT NULL,
   PRIMARY KEY (id),
   UNIQUE (sso_id)
)

create table USER_PROFILE(
   id BIGINT NOT NULL AUTO_INCREMENT,
   type VARCHAR(30) NOT NULL,
   PRIMARY KEY (id),
   UNIQUE (type)
)

CREATE TABLE APP_USER_USER_PROFILE (
    user_id BIGINT NOT NULL,
    user_profile_id BIGINT NOT NULL,
    PRIMARY KEY (user_id, user_profile_id),
    CONSTRAINT FK_APP_USER FOREIGN KEY (user_id) REFERENCES APP_USER (id),
    CONSTRAINT FK_USER_PROFILE FOREIGN KEY (user_profile_id) REFERENCES USER_PROFILE (id)
)

/* Populate USER_PROFILE Table */
INSERT INTO USER_PROFILE(type)
VALUES (&aposUSER&apos)

INSERT INTO USER_PROFILE(type)
VALUES (&aposADMIN&apos)

INSERT INTO USER_PROFILE(type)
VALUES (&aposDBA&apos)

commit

第2步：创建目录结构

以下是最终的项目结构：

第3步：更新pom.xml，包括所需的依赖关系

<project xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"
	xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
	<modelVersion>4.0.0</modelVersion>
	<groupId>com.yiibai.springmvc</groupId>
	<artifactId>SpringMVCMany2ManyCRUD</artifactId>
	<packaging>war</packaging>
	<version>1.0.0</version>
	<name>SpringMVCHibernateManyToManyCRUDExample</name>

  	<properties>
		<springframework.version>4.1.7.RELEASE</springframework.version>
		<hibernate.version>4.3.10.Final</hibernate.version>
		<mysql.connector.version>5.1.31</mysql.connector.version>
	</properties>

	<dependencies>
		<!-- Spring -->
		<dependency>
			<groupId>org.springframework</groupId>
			<artifactId>spring-core</artifactId>
			<version>${springframework.version}</version>
		</dependency>
		<dependency>
			<groupId>org.springframework</groupId>
			<artifactId>spring-web</artifactId>
			<version>${springframework.version}</version>
		</dependency>
		<dependency>
			<groupId>org.springframework</groupId>
			<artifactId>spring-webmvc</artifactId>
			<version>${springframework.version}</version>
		</dependency>
		<dependency>
			<groupId>org.springframework</groupId>
			<artifactId>spring-tx</artifactId>
			<version>${springframework.version}</version>
		</dependency>
		<dependency>
			<groupId>org.springframework</groupId>
			<artifactId>spring-orm</artifactId>
			<version>${springframework.version}</version>
		</dependency>

		<!-- Hibernate -->
		<dependency>
			<groupId>org.hibernate</groupId>
			<artifactId>hibernate-core</artifactId>
			<version>${hibernate.version}</version>
		</dependency>

		<!-- jsr303 validation -->
		<dependency>
			<groupId>javax.validation</groupId>
			<artifactId>validation-api</artifactId>
			<version>1.1.0.Final</version>
		</dependency>
		<dependency>
			<groupId>org.hibernate</groupId>
			<artifactId>hibernate-validator</artifactId>
			<version>5.1.3.Final</version>
		</dependency>

		<!-- MySQL -->
		<dependency>
			<groupId>mysql</groupId>
			<artifactId>mysql-connector-java</artifactId>
			<version>${mysql.connector.version}</version>
		</dependency>

		<!-- Servlet+JSP+JSTL -->
		<dependency>
			<groupId>javax.servlet</groupId>
			<artifactId>javax.servlet-api</artifactId>
			<version>3.1.0</version>
		</dependency>
		<dependency>
			<groupId>javax.servlet.jsp</groupId>
			<artifactId>javax.servlet.jsp-api</artifactId>
			<version>2.3.1</version>
		</dependency>
		<dependency>
		    <groupId>javax.servlet</groupId>
		    <artifactId>jstl</artifactId>
		    <version>1.2</version>
		</dependency>
		
	</dependencies>

	<build>
		<pluginManagement>
			<plugins>
				<plugin>
					<groupId>org.apache.maven.plugins</groupId>
					<artifactId>maven-war-plugin</artifactId>
					<version>2.4</version>
					<configuration>
						<warSourceDirectory>src/main/webapp</warSourceDirectory>
						<warName>SpringMVCMany2ManyCRUD</warName> <failOnMissingWebXml>false</failOnMissingWebXml>
					</configuration>
				</plugin>
			</plugins>
		</pluginManagement>
		<finalName>SpringMVCMany2ManyCRUD</finalName>
	</build>
</project>

第4步：准备Model类

package com.yiibai.springmvc.model

import java.util.HashSet
import java.util.Set

import javax.persistence.Column
import javax.persistence.Entity
import javax.persistence.FetchType
import javax.persistence.GeneratedValue
import javax.persistence.GenerationType
import javax.persistence.Id
import javax.persistence.JoinColumn
import javax.persistence.JoinTable
import javax.persistence.ManyToMany
import javax.persistence.Table

import org.hibernate.validator.constraints.NotEmpty

@Entity
@Table(name="APP_USER")
public class User {

	@Id @GeneratedValue(strategy=GenerationType.IDENTITY)
	private Integer id

	@NotEmpty
	@Column(name="SSO_ID", unique=true, nullable=false)
	private String ssoId
	
	@NotEmpty
	@Column(name="PASSWORD", nullable=false)
	private String password
		
	@NotEmpty
	@Column(name="FIRST_NAME", nullable=false)
	private String firstName

	@NotEmpty
	@Column(name="LAST_NAME", nullable=false)
	private String lastName

	@NotEmpty
	@Column(name="EMAIL", nullable=false)
	private String email

	@NotEmpty
	@ManyToMany(fetch = FetchType.LAZY)
	@JoinTable(name = "APP_USER_USER_PROFILE", 
             joinColumns = { @JoinColumn(name = "USER_ID") }, 
             inverseJoinColumns = { @JoinColumn(name = "USER_PROFILE_ID") })
	private Set<UserProfile> userProfiles = new HashSet<UserProfile>()

	public Integer getId() {
		return id
	}

	public void setId(Integer id) {
		this.id = id
	}

	public String getSsoId() {
		return ssoId
	}

	public void setSsoId(String ssoId) {
		this.ssoId = ssoId
	}

	public String getPassword() {
		return password
	}

	public void setPassword(String password) {
		this.password = password
	}

	public String getFirstName() {
		return firstName
	}

	public void setFirstName(String firstName) {
		this.firstName = firstName
	}

	public String getLastName() {
		return lastName
	}

	public void setLastName(String lastName) {
		this.lastName = lastName
	}

	public String getEmail() {
		return email
	}

	public void setEmail(String email) {
		this.email = email
	}

	public Set<UserProfile> getUserProfiles() {
		return userProfiles
	}

	public void setUserProfiles(Set<UserProfile> userProfiles) {
		this.userProfiles = userProfiles
	}

	@Override
	public int hashCode() {
		final int prime = 31
		int result = 1
		result = prime * result + ((id == null) ? 0 : id.hashCode())
		result = prime * result + ((ssoId == null) ? 0 : ssoId.hashCode())
		return result
	}

	@Override
	public boolean equals(Object obj) {
		if (this == obj)
			return true
		if (obj == null)
			return false
		if (!(obj instanceof User))
			return false
		User other = (User) obj
		if (id == null) {
			if (other.id != null)
				return false
		} else if (!id.equals(other.id))
			return false
		if (ssoId == null) {
			if (other.ssoId != null)
				return false
		} else if (!ssoId.equals(other.ssoId))
			return false
		return true
	}

	@Override
	public String toString() {
		return "User [id=" + id + ", ssoId=" + ssoId + ", password=" + password
				+ ", firstName=" + firstName + ", lastName=" + lastName
				+ ", email=" + email + "]"
	}

}

再看看 UserProfiles%uA0属性是如何标注了多对多。

@ManyToMany表示用户和用户配置之间有多到多关系。一个用户可以有多个资料[USER，ADMIN，DBA]用户资料信息可以属于多个用户。@JoinTable表示它使用两个表的表外键链接来约束自己的主键。这个注解，主要用于关系的拥有方。joinColumns是指拥有方(用户ID)的列名，inverseJoinColumns是指关系的反向端(USER_PROFILE的ID)的列。这个连接表的主键是USER_ID%uA0&%uA0USER_PROFILE_ID%uA0组合。

延迟加载：

要特别注意fetch%uA0=ꃾtchType.LAZY。在这里，我们通知%uA0Hibernate%uA0懒加载用户资料集合。%uA0这也是默认的行为。在此设置中，首先访问仅当查询加载集合将被触发。这是一个很好的方式，以避免加载-这是一个昂贵的操作所有连接的对象。%uA0当在事务/活动会话，并会尝试访问集合，Hibernate会触发不同的选择来获取它们。

但是，如果您不在活动的会话(会话关闭/无事务：如在JSP)，并试图访问集合，你会遇到报应:org.hibernate.LazyInitializationException – could not initialize proxy – no Session.%uA0为了避免它，需要通过调用 Hibernate.initialize(user.getUserProfiles())%uA0来初始化对需要的集合%uA0在有效会话中[在DAO方法，在显示视图之前，可以调用这个初始化方法]。

还要注意的是，我们没有使用任何级联。这是因为用户个人资料不依赖用户，并能独立生存。

重要：如果是*Many*%uA0关联它总是覆盖 hashCode 和 equals 方法，它是通过%uA0Hibernate%uA0持有合并形成集合。

package com.yiibai.springmvc.model

import javax.persistence.Column
import javax.persistence.Entity
import javax.persistence.GeneratedValue
import javax.persistence.GenerationType
import javax.persistence.Id
import javax.persistence.Table

@Entity
@Table(name="USER_PROFILE")
public class UserProfile {

	@Id @GeneratedValue(strategy=GenerationType.IDENTITY)
	private Integer id	

	@Column(name="TYPE", length=15, unique=true, nullable=false)
	private String type = UserProfileType.USER.getUserProfileType()
	
	public Integer getId() {
		return id
	}

	public void setId(Integer id) {
		this.id = id
	}

	public String getType() {
		return type
	}

	public void setType(String type) {
		this.type = type
	}

	@Override
	public int hashCode() {
		final int prime = 31
		int result = 1
		result = prime * result + ((id == null) ? 0 : id.hashCode())
		result = prime * result + ((type == null) ? 0 : type.hashCode())
		return result
	}

	@Override
	public boolean equals(Object obj) {
		if (this == obj)
			return true
		if (obj == null)
			return false
		if (!(obj instanceof UserProfile))
			return false
		UserProfile other = (UserProfile) obj
		if (id == null) {
			if (other.id != null)
				return false
		} else if (!id.equals(other.id))
			return false
		if (type == null) {
			if (other.type != null)
				return false
		} else if (!type.equals(other.type))
			return false
		return true
	}

	@Override
	public String toString() {
		return "UserProfile [id=" + id + ", type=" + type + "]"
	}

}

既然我们都显示单向关系(User到UserProfile)，无须参考用户UserProfile。

package com.yiibai.springmvc.model

public enum UserProfileType {
	USER("USER"),
	DBA("DBA"),
	ADMIN("ADMIN")
	
	String userProfileType
	
	private UserProfileType(String userProfileType){
		this.userProfileType = userProfileType
	}
	
	public String getUserProfileType(){
		return userProfileType
	}
	
}

第5步：创建DAO层

package com.yiibai.springmvc.dao

import java.util.List

import com.yiibai.springmvc.model.User


public interface UserDao {

	User findById(int id)
	
	User findBySSO(String sso)
	
	void save(User user)
	
	void deleteBySSO(String sso)
	
	List<User> findAllUsers()

}

package com.yiibai.springmvc.dao

import java.util.List

import com.yiibai.springmvc.model.UserProfile


public interface UserProfileDao {

	List<UserProfile> findAll()
	
	UserProfile findByType(String type)
	
	UserProfile findById(int id)
}

package com.yiibai.springmvc.dao

import java.io.Serializable

import java.lang.reflect.ParameterizedType

import org.hibernate.Criteria
import org.hibernate.Session
import org.hibernate.SessionFactory
import org.springframework.beans.factory.annotation.Autowired

public abstract class AbstractDao<PK extends Serializable, T> {
	
	private final Class<T> persistentClass
	
	@SuppressWarnings("unchecked")
	public AbstractDao(){
		this.persistentClass =(Class<T>) ((ParameterizedType) this.getClass().getGenericSuperclass

()).getActualTypeArguments()[1]
	}
	
	@Autowired
	private SessionFactory sessionFactory

	protected Session getSession(){
		return sessionFactory.getCurrentSession()
	}

	@SuppressWarnings("unchecked")
	public T getByKey(PK key) {
		return (T) getSession().get(persistentClass, key)
	}

	public void persist(T entity) {
		getSession().persist(entity)
	}

	public void delete(T entity) {
		getSession().delete(entity)
	}
	
	protected Criteria createEntityCriteria(){
		return getSession().createCriteria(persistentClass)
	}

}

package com.yiibai.springmvc.dao

import java.util.List

import org.hibernate.Criteria
import org.hibernate.Hibernate
import org.hibernate.criterion.Order
import org.hibernate.criterion.Restrictions
import org.springframework.stereotype.Repository

import com.yiibai.springmvc.model.User

@Repository("userDao")
public class UserDaoImpl extends AbstractDao<Integer, User> implements UserDao {

	public User findById(int id) {
		User user = getByKey(id)
		if(user!=null){
			Hibernate.initialize(user.getUserProfiles())
		}
		return user
	}

	public User findBySSO(String sso) {
		System.out.println("SSO : "+sso)
		Criteria crit = createEntityCriteria()
		crit.add(Restrictions.eq("ssoId", sso))
		User user = (User)crit.uniqueResult()
		if(user!=null){
			Hibernate.initialize(user.getUserProfiles())
		}
		return user
	}

	@SuppressWarnings("unchecked")
	public List<User> findAllUsers() {
		Criteria criteria = createEntityCriteria().addOrder(Order.asc("firstName"))
		criteria.setResultTransformer(Criteria.DISTINCT_ROOT_ENTITY)//To avoid duplicates.
		List<User> users = (List<User>) criteria.list()
		
		// No need to fetch userProfiles since we are not showing them on list page. Let them lazy load. 
		// Uncomment below lines for eagerly fetching of userProfiles if you want.
		/*
		for(User user : users){
			Hibernate.initialize(user.getUserProfiles())
		}*/
		return users
	}

	public void save(User user) {
		persist(user)
	}

	public void deleteBySSO(String sso) {
		Criteria crit = createEntityCriteria()
		crit.add(Restrictions.eq("ssoId", sso))
		User user = (User)crit.uniqueResult()
		delete(user)
	}

}

package com.yiibai.springmvc.dao

import java.util.List

import org.hibernate.Criteria
import org.hibernate.criterion.Order
import org.hibernate.criterion.Restrictions
import org.springframework.stereotype.Repository

import com.yiibai.springmvc.model.UserProfile

@Repository("userProfileDao")
public class UserProfileDaoImpl extends AbstractDao<Integer, UserProfile>implements UserProfileDao{

	public UserProfile findById(int id) {
		return getByKey(id)
	}

	public UserProfile findByType(String type) {
		Criteria crit = createEntityCriteria()
		crit.add(Restrictions.eq("type", type))
		return (UserProfile) crit.uniqueResult()
	}
	
	@SuppressWarnings("unchecked")
	public List<UserProfile> findAll(){
		Criteria crit = createEntityCriteria()
		crit.addOrder(Order.asc("type"))
		return (List<UserProfile>)crit.list()
	}
	
}

第6步：创建服务层

package com.yiibai.springmvc.service

import java.util.List
import com.yiibai.springmvc.model.UserProfile

public interface UserProfileService {

	UserProfile findById(int id)

	UserProfile findByType(String type)
	
	List<UserProfile> findAll()
	
}

package com.yiibai.springmvc.service

import java.util.List
import com.yiibai.springmvc.model.User

public interface UserService {
	
	User findById(int id)
	
	User findBySSO(String sso)
	
	void saveUser(User user)
	
	void updateUser(User user)
	
	void deleteUserBySSO(String sso)

	List<User> findAllUsers() 
	
	boolean isUserSSOUnique(Integer id, String sso)

}

package com.yiibai.springmvc.service

import java.util.List

import org.springframework.beans.factory.annotation.Autowired
import org.springframework.stereotype.Service
import org.springframework.transaction.annotation.Transactional

import com.yiibai.springmvc.dao.UserProfileDao
import com.yiibai.springmvc.model.UserProfile

@Service("userProfileService")
@Transactional
public class UserProfileServiceImpl implements UserProfileService{
	
	@Autowired
	UserProfileDao dao
	
	public UserProfile findById(int id) {
		return dao.findById(id)
	}

	public UserProfile findByType(String type){
		return dao.findByType(type)
	}

	public List<UserProfile> findAll() {
		return dao.findAll()
	}
}

package com.yiibai.springmvc.service

import java.util.List

import org.springframework.beans.factory.annotation.Autowired
import org.springframework.stereotype.Service
import org.springframework.transaction.annotation.Transactional

import com.yiibai.springmvc.dao.UserDao
import com.yiibai.springmvc.model.User

@Service("userService")
@Transactional
public class UserServiceImpl implements UserService{

	@Autowired
	private UserDao dao

	public User findById(int id) {
		return dao.findById(id)
	}

	public User findBySSO(String sso) {
		User user = dao.findBySSO(sso)
		return user
	}

	public void saveUser(User user) {
		dao.save(user)
	}

	/*
	 * Since the method is running with Transaction, No need to call hibernate update explicitly.
	 * Just fetch the entity from db and update it with proper values within transaction.
	 * It will be updated in db once transaction ends. 
	 */
	public void updateUser(User user) {
		User entity = dao.findById(user.getId())
		if(entity!=null){
			entity.setSsoId(user.getSsoId())
			entity.setPassword(user.getPassword())
			entity.setFirstName(user.getFirstName())
			entity.setLastName(user.getLastName())
			entity.setEmail(user.getEmail())
			entity.setUserProfiles(user.getUserProfiles())
		}
	}

	
	public void deleteUserBySSO(String sso) {
		dao.deleteBySSO(sso)
	}

	public List<User> findAllUsers() {
		return dao.findAllUsers()
	}

	public boolean isUserSSOUnique(Integer id, String sso) {
		User user = findBySSO(sso)
		return ( user == null || ((id != null) && (user.getId() == id)))
	}
	
}

第7步：创建Hibernate配置

package com.yiibai.springmvc.configuration

import java.util.Properties
import javax.sql.DataSource

import org.hibernate.SessionFactory
import org.springframework.beans.factory.annotation.Autowired
import org.springframework.context.annotation.Bean
import org.springframework.context.annotation.ComponentScan
import org.springframework.context.annotation.Configuration
import org.springframework.context.annotation.PropertySource
import org.springframework.core.env.Environment
import org.springframework.jdbc.datasource.DriverManagerDataSource
import org.springframework.orm.hibernate4.HibernateTransactionManager
import org.springframework.orm.hibernate4.LocalSessionFactoryBean
import org.springframework.transaction.annotation.EnableTransactionManagement

@Configuration
@EnableTransactionManagement
@ComponentScan({ "com.yiibai.springmvc.configuration" })
@PropertySource(value = { "classpath:application.properties" })
public class HibernateConfiguration {

    @Autowired
    private Environment environment

    @Bean
    public LocalSessionFactoryBean sessionFactory() {
        LocalSessionFactoryBean sessionFactory = new LocalSessionFactoryBean()
        sessionFactory.setDataSource(dataSource())
        sessionFactory.setPackagesToScan(new String[] { "com.yiibai.springmvc.model" })
        sessionFactory.setHibernateProperties(hibernateProperties())
        return sessionFactory
     }
	
    @Bean
    public DataSource dataSource() {
        DriverManagerDataSource dataSource = new DriverManagerDataSource()
        dataSource.setDriverClassName(environment.getRequiredProperty("jdbc.driverClassName"))
        dataSource.setUrl(environment.getRequiredProperty("jdbc.url"))
        dataSource.setUsername(environment.getRequiredProperty("jdbc.username"))
        dataSource.setPassword(environment.getRequiredProperty("jdbc.password"))
        return dataSource
    }
    
    private Properties hibernateProperties() {
        Properties properties = new Properties()
        properties.put("hibernate.dialect", environment.getRequiredProperty("hibernate.dialect"))
        properties.put("hibernate.show_sql", environment.getRequiredProperty("hibernate.show_sql"))
        properties.put("hibernate.format_sql", environment.getRequiredProperty("hibernate.format_sql"))
        return properties        
    }
    
	@Bean
    @Autowired
    public HibernateTransactionManager transactionManager(SessionFactory s) {
       HibernateTransactionManager txManager = new HibernateTransactionManager()
       txManager.setSessionFactory(s)
       return txManager
    }
}

以上 Hibernate 的配置使用下面提到 application.properties

jdbc.driverClassName = com.mysql.jdbc.Driver
jdbc.url = jdbc:mysql://localhost:3306/yiibai
jdbc.username = myuser
jdbc.password = passwd123
hibernate.dialect = org.hibernate.dialect.MySQLDialect
hibernate.show_sql = true
hibernate.format_sql = true

第8步：创建控制器

package com.yiibai.springmvc.controller

import java.util.List
import java.util.Locale

import javax.validation.Valid

import org.springframework.beans.factory.annotation.Autowired
import org.springframework.context.MessageSource
import org.springframework.stereotype.Controller
import org.springframework.ui.ModelMap
import org.springframework.validation.BindingResult
import org.springframework.validation.FieldError
import org.springframework.web.bind.annotation.ModelAttribute
import org.springframework.web.bind.annotation.PathVariable
import org.springframework.web.bind.annotation.RequestMapping
import org.springframework.web.bind.annotation.RequestMethod
import org.springframework.web.bind.annotation.SessionAttributes

import com.yiibai.springmvc.model.User
import com.yiibai.springmvc.model.UserProfile
import com.yiibai.springmvc.service.UserProfileService
import com.yiibai.springmvc.service.UserService

@Controller
@RequestMapping("/")
@SessionAttributes("roles")
public class AppController {

	@Autowired
	UserService userService
	
	@Autowired
	UserProfileService userProfileService
		
	@Autowired
	MessageSource messageSource

	/**
	 * This method will list all existing users.
	 */
	@RequestMapping(value = { "/", "/list" }, method = RequestMethod.GET)
	public String listUsers(ModelMap model) {

		List<User> users = userService.findAllUsers()
		model.addAttribute("users", users)
		return "userslist"
	}

	/**
	 * This method will provide the medium to add a new user.
	 */
	@RequestMapping(value = { "/newuser" }, method = RequestMethod.GET)
	public String newUser(ModelMap model) {
		User user = new User()
		model.addAttribute("user", user)
		model.addAttribute("edit", false)
		return "registration"
	}

	/**
	 * This method will be called on form submission, handling POST request for
	 * saving user in database. It also validates the user input
	 */
	@RequestMapping(value = { "/newuser" }, method = RequestMethod.POST)
	public String saveUser(@Valid User user, BindingResult result,
			ModelMap model) {

		if (result.hasErrors()) {
			return "registration"
		}

		/*
		 * Preferred way to achieve uniqueness of field [sso] should be implementing custom @Unique annotation 
		 * and applying it on field [sso] of Model class [User].
		 * 
		 * Below mentioned peace of code [if block] is to demonstrate that you can fill custom errors outside the 

validation
		 * framework as well while still using internationalized messages.
		 * 
		 */
		if(!userService.isUserSSOUnique(user.getId(), user.getSsoId())){
			FieldError ssoError =new FieldError("user","ssoId",messageSource.getMessage("non.unique.ssoId", new 

String[]{user.getSsoId()}, Locale.getDefault()))
		    result.addError(ssoError)
			return "registration"
		}
		
		userService.saveUser(user)

		model.addAttribute("success", "User " + user.getFirstName() + " "+ user.getLastName() + " registered 

successfully")
		//return "success"
		return "registrationsuccess"
	}


	/**
	 * This method will provide the medium to update an existing user.
	 */
	@RequestMapping(value = { "/edit-user-{ssoId}" }, method = RequestMethod.GET)
	public String editUser(@PathVariable String ssoId, ModelMap model) {
		User user = userService.findBySSO(ssoId)
		model.addAttribute("user", user)
		model.addAttribute("edit", true)
		return "registration"
	}
	
	/**
	 * This method will be called on form submission, handling POST request for
	 * updating user in database. It also validates the user input
	 */
	@RequestMapping(value = { "/edit-user-{ssoId}" }, method = RequestMethod.POST)
	public String updateUser(@Valid User user, BindingResult result,
			ModelMap model, @PathVariable String ssoId) {

		if (result.hasErrors()) {
			return "registration"
		}

		/*//Uncomment below &aposif block&apos if you WANT TO ALLOW UPDATING SSO_ID in UI which is a unique key to a User.
		if(!userService.isUserSSOUnique(user.getId(), user.getSsoId())){
			FieldError ssoError =new FieldError("user","ssoId",messageSource.getMessage("non.unique.ssoId", new 

String[]{user.getSsoId()}, Locale.getDefault()))
		    result.addError(ssoError)
			return "registration"
		}*/

		userService.updateUser(user)

		model.addAttribute("success", "User " + user.getFirstName() + " "+ user.getLastName() + " updated successfully")
		return "registrationsuccess"
	}

	
	/**
	 * This method will delete an user by it&aposs SSOID value.
	 */
	@RequestMapping(value = { "/delete-user-{ssoId}" }, method = RequestMethod.GET)
	public String deleteUser(@PathVariable String ssoId) {
		userService.deleteUserBySSO(ssoId)
		return "redirect:/list"
	}
	

	/**
	 * This method will provide UserProfile list to views
	 */
	@ModelAttribute("roles")
	public List<UserProfile> initializeProfiles() {
		return userProfileService.findAll()
	}

}

在下面提到的 messages.properties 文件中定义消息

NotEmpty.user.firstName=First name can not be blank.
NotEmpty.user.lastName=Last name can not be blank.
NotEmpty.user.email=Email can not be blank.
NotEmpty.user.password=Password can not be blank.
NotEmpty.user.ssoId=SSO ID can not be blank.
NotEmpty.user.userProfiles=At least one profile must be selected.
non.unique.ssoId=SSO ID {0} already exist. Please fill in different value.

第9步：创建转换器

这是这篇文章的核心。是需要映射单个%uA0userProfile%uA0的ID在实际的%uA0UserProfile%uA0实体在数据库中。

package com.yiibai.springmvc.converter

import org.springframework.beans.factory.annotation.Autowired
import org.springframework.core.convert.converter.Converter
import org.springframework.stereotype.Component

import com.yiibai.springmvc.model.UserProfile
import com.yiibai.springmvc.service.UserProfileService

/**
 * A converter class used in views to map id&aposs to actual userProfile objects.
 */
@Component
public class RoleToUserProfileConverter implements Converter<Object, UserProfile>{

	@Autowired
	UserProfileService userProfileService

	/**
	 * Gets UserProfile by Id
	 * @see org.springframework.core.convert.converter.Converter#convert(java.lang.Object)
	 */
	public UserProfile convert(Object element) {
		Integer id = Integer.parseInt((String)element)
		UserProfile profile= userProfileService.findById(id)
		System.out.println("Profile : "+profile)
		return profile
	}
	
}

第10步、创建Spring配置文件

package com.yiibai.springmvc.configuration

import org.springframework.beans.factory.annotation.Autowired
import org.springframework.context.MessageSource
import org.springframework.context.annotation.Bean
import org.springframework.context.annotation.ComponentScan
import org.springframework.context.annotation.Configuration
import org.springframework.context.support.ResourceBundleMessageSource
import org.springframework.format.FormatterRegistry
import org.springframework.web.servlet.config.annotation.EnableWebMvc
import org.springframework.web.servlet.config.annotation.PathMatchConfigurer
import org.springframework.web.servlet.config.annotation.ResourceHandlerRegistry
import org.springframework.web.servlet.config.annotation.ViewResolverRegistry
import org.springframework.web.servlet.config.annotation.WebMvcConfigurerAdapter
import org.springframework.web.servlet.view.InternalResourceViewResolver
import org.springframework.web.servlet.view.JstlView

import com.yiibai.springmvc.converter.RoleToUserProfileConverter

@Configuration
@EnableWebMvc
@ComponentScan(basePackages = "com.yiibai.springmvc")
public class AppConfig extends WebMvcConfigurerAdapter{
	
	@Autowired
	RoleToUserProfileConverter roleToUserProfileConverter
	
	/**
     * Configure ViewResolvers to deliver preferred views.
     */
	@Override
	public void configureViewResolvers(ViewResolverRegistry registry) {

		InternalResourceViewResolver viewResolver = new InternalResourceViewResolver()
		viewResolver.setViewClass(JstlView.class)
		viewResolver.setPrefix("/WEB-INF/views/")
		viewResolver.setSuffix(".jsp")
		registry.viewResolver(viewResolver)
	}
	
	/**
     * Configure ResourceHandlers to serve static resources like CSS/ Javascript etc...
     */
    @Override
    public void addResourceHandlers(ResourceHandlerRegistry registry) {
        registry.addResourceHandler("/static/**").addResourceLocations("/static/")
    }
    
    /**
     * Configure Converter to be used.
     * In our example, we need a converter to convert string values[Roles] to UserProfiles in newUser.jsp
     */
    @Override
    public void addFormatters(FormatterRegistry registry) {
        registry.addConverter(roleToUserProfileConverter)
    }
	

    /**
     * Configure MessageSource to lookup any validation/error message in internationalized property files
     */
    @Bean
	public MessageSource messageSource() {
	    ResourceBundleMessageSource messageSource = new ResourceBundleMessageSource()
	    messageSource.setBasename("messages")
	    return messageSource
	}
    
    /**Optional. It&aposs only required when handling &apos.&apos in @PathVariables which otherwise ignore everything after last &apos.&apos in 

@PathVaidables argument.
     * It&aposs a known bug in Spring [https://jira.spring.io/browse/SPR-6164], still present in Spring 4.1.7.
     * This is a workaround for this issue.
     */
    @Override
    public void configurePathMatch(PathMatchConfigurer matcher) {
        matcher.setUseRegisteredSuffixPatternMatch(true)
    }
}%uA0

第一个有趣的事情是注册转换器，我们在上一步中使用addFormatters创建了Spring配置。其次是方法configurePathMatch它提供了一个解决方法(虽然其他解决方法存在)在Spring中是一个已知的错误，这仍然在Spring4.1.7.RELEASE中有发现。

上述XML配置转换器设置为：

	<mvc:annotation-driven conversion-service="conversionService"/>

	<bean id="conversionService" class="org.springframework.format.support.FormattingConversionServiceFactoryBean">
	
		<property name="converters">
			<list>
				<bean id="roleToUserProfile" class="com.yiibai.springsecurity.configuration.RoleToUserProfileConverter" />
			</list>
		</property>
	</bean>

添加初始化类：

package com.yiibai.springmvc.configuration

import org.springframework.web.servlet.support.AbstractAnnotationConfigDispatcherServletInitializer

public class AppInitializer extends AbstractAnnotationConfigDispatcherServletInitializer {

	@Override
	protected Class<?>[] getRootConfigClasses() {
		return new Class[] { AppConfig.class }
	}
 
	@Override
	protected Class<?>[] getServletConfigClasses() {
		return null
	}
 
	@Override
	protected String[] getServletMappings() {
		return new String[] { "/" }
	}

}

第11步：添加视图/%uA0JSP

请注意，我们使用 Bootstrap 样式在JSP中。

userslist.jsp

<%@ page language="java" contentType="text/html charset=ISO-8859-1" pageEncoding="ISO-8859-1"%>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<html>

<head>
	<meta http-equiv="Content-Type" content="text/html charset=ISO-8859-1">
	<title>Users List</title>
	<link href="<c:url value=&apos/static/css/bootstrap.css&apos />" rel="stylesheet"></link>
	<link href="<c:url value=&apos/static/css/app.css&apos />" rel="stylesheet"></link>
</head>

<body>
	<div class="generic-container">
		<div class="panel panel-default">
			  <!-- Default panel contents -->
		  	<div class="panel-heading"><span class="lead">List of Users </span></div>
			<table class="table table-hover">
	    		<thead>
		      		<tr>
				        <th>Firstname</th>
				        <th>Lastname</th>
				        <th>Email</th>
				        <th>SSO ID</th>
				        <th width="100"></th>
				        <th width="100"></th>
					</tr>
		    	</thead>
	    		<tbody>
				<c:forEach items="${users}" var="user">
					<tr>
						<td>${user.firstName}</td>
						<td>${user.lastName}</td>
						<td>${user.email}</td>
						<td>${user.ssoId}</td>
						<td><a href="<c:url value=&apos/edit-user-${user.ssoId}&apos />" class="btn btn-success 

custom-width">edit</a></td>
						<td><a href="<c:url value=&apos/delete-user-${user.ssoId}&apos />" class="btn btn-danger 

custom-width">delete</a></td>
					</tr>
				</c:forEach>
	    		</tbody>
	    	</table>
		</div>
	 	<div class="well">
	 		<a href="<c:url value=&apos/newuser&apos />">Add New User</a>
	 	</div>
   	</div>
</body>
</html>

registration.jsp

<%@ page language="java" contentType="text/html charset=ISO-8859-1" pageEncoding="ISO-8859-1"%>
<%@ taglib prefix="form" uri="http://www.springframework.org/tags/form"%>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>

<html>

<head>
	<meta http-equiv="Content-Type" content="text/html charset=ISO-8859-1">
	<title>User Registration Form</title>
	<link href="<c:url value=&apos/static/css/bootstrap.css&apos />" rel="stylesheet"></link>
	<link href="<c:url value=&apos/static/css/app.css&apos />" rel="stylesheet"></link>
</head>

<body>

 	<div class="generic-container">
	<div class="well lead">User Registration Form</div>
 	<form:form method="POST" modelAttribute="user" class="form-horizontal">
		<form:input type="hidden" path="id" id="id"/>
		
		<div class="row">
			<div class="form-group col-md-12">
				<label class="col-md-3 control-lable" for="firstName">First Name</label>
				<div class="col-md-7">
					<form:input type="text" path="firstName" id="firstName" class="form-control input-sm"/>
					<div class="has-error">
						<form:errors path="firstName" class="help-inline"/>
					</div>
				</div>
			</div>
		</div>

		<div class="row">
			<div class="form-group col-md-12">
				<label class="col-md-3 control-lable" for="lastName">Last Name</label>
				<div class="col-md-7">
					<form:input type="text" path="lastName" id="lastName" class="form-control input-sm" />
					<div class="has-error">
						<form:errors path="lastName" class="help-inline"/>
					</div>
				</div>
			</div>
		</div>

		<div class="row">
			<div class="form-group col-md-12">
				<label class="col-md-3 control-lable" for="ssoId">SSO ID</label>
				<div class="col-md-7">
					<c:choose>
						<c:when test="${edit}">
							<form:input type="text" path="ssoId" id="ssoId" class="form-control 

input-sm" disabled="true"/>
						</c:when>
						<c:otherwise>
							<form:input type="text" path="ssoId" id="ssoId" class="form-control 

input-sm" />
							<div class="has-error">
								<form:errors path="ssoId" class="help-inline"/>
							</div>
						</c:otherwise>
					</c:choose>
				</div>
			</div>
		</div>

		<div class="row">
			<div class="form-group col-md-12">
				<label class="col-md-3 control-lable" for="password">Password</label>
				<div class="col-md-7">
					<form:input type="password" path="password" id="password" class="form-control input-sm" 

/>
					<div class="has-error">
						<form:errors path="password" class="help-inline"/>
					</div>
				</div>
			</div>
		</div>

		<div class="row">
			<div class="form-group col-md-12">
				<label class="col-md-3 control-lable" for="email">Email</label>
				<div class="col-md-7">
					<form:input type="text" path="email" id="email" class="form-control input-sm" />
					<div class="has-error">
						<form:errors path="email" class="help-inline"/>
					</div>
				</div>
			</div>
		</div>

		<div class="row">
			<div class="form-group col-md-12">
				<label class="col-md-3 control-lable" for="userProfiles">Roles</label>
				<div class="col-md-7">
					<form:select path="userProfiles" items="${roles}" multiple="true" itemValue="id" 

itemLabel="type" class="form-control input-sm" />
					<div class="has-error">
						<form:errors path="userProfiles" class="help-inline"/>
					</div>
				</div>
			</div>
		</div>

		<div class="row">
			<div class="form-actions floatRight">
				<c:choose>
					<c:when test="${edit}">
						<input type="submit" value="Update" class="btn btn-primary btn-sm"/> or <a 

href="<c:url value=&apos/list&apos />">Cancel</a>
					</c:when>
					<c:otherwise>
						<input type="submit" value="Register" class="btn btn-primary btn-sm"/> or <a 

href="<c:url value=&apos/list&apos />">Cancel</a>
					</c:otherwise>
				</c:choose>
			</div>
		</div>
	</form:form>
	</div>
</body>
</html>

registrationsuccess.jsp

<%@ page language="java" contentType="text/html charset=ISO-8859-1" pageEncoding="ISO-8859-1"%>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>


<html>
<head>
	<meta http-equiv="Content-Type" content="text/html charset=ISO-8859-1">
	<title>Registration Confirmation Page</title>
	<link href="<c:url value=&apos/static/css/bootstrap.css&apos />" rel="stylesheet"></link>
	<link href="<c:url value=&apos/static/css/app.css&apos />" rel="stylesheet"></link>
</head>
<body>
<div class="generic-container">
	<div class="alert alert-success lead">
    	${success}
	</div>
	
	<span class="well floatRight">
		Go to <a href="<c:url value=&apos/list&apos />">Users List</a>
	</span>
</div>
</body>

</html>

这里是一个小自定义样式表文件：

app.css

body, #mainWrapper {
	height: 100%
	background-color:rgb(245, 245, 245)
}

body, .form-control{
	font-size:14px!important
}

.floatRight{
	float:right
	margin-right: 18px
}

.has-error{
	color:red
}

.generic-container {
  position:fixed
  width:80%
  margin-left: 20px
  margin-top: 20px
  margin-bottom: 20px
  padding: 20px
  background-color: #EAE7E7
  border: 1px solid #ddd
  border-radius: 4px
  box-shadow: 0 0 30px black
}

.custom-width {
    width: 80px !important
}