SpringMVC联手REST实现入门级的CRUD

这是一个WebProject，用到的是spring-framework-3.1.1.RELEASE

首先是web.xml

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<?xml version="1.0" encoding="UTF-8"?>

<web-app version="2.5"

xmlns="http://java.sun.com/xml/ns/javaee"

xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

xsi:schemaLocation="http://java.sun.com/xml/ns/javaee
http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">
<servlet>

<servlet-name>user</servlet-name>

<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>

<load-on-startup>1</load-on-startup>

</servlet>

<servlet-mapping>

<servlet-name>user</servlet-name>

<url-pattern>/</url-pattern>

</servlet-mapping>

<filter>

<filter-name>SpringCharacterEncodingFilter</filter-name>

<filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class>

<init-param>

<param-name>encoding</param-name>

<param-value>UTF-8</param-value>

</init-param>

</filter>

<filter-mapping>

<filter-name>SpringCharacterEncodingFilter</filter-name>

<url-pattern>/*</url-pattern>

</filter-mapping>

</web-app>

然后是SpringMVC的配置文件user-servlet.xml

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<?xml version="1.0" encoding="UTF-8"?>

<beans xmlns="http://www.springframework.org/schema/beans"

xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

xmlns:mvc="http://www.springframework.org/schema/mvc"

xmlns:context="http://www.springframework.org/schema/context"

xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-3.0.xsd http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-3.1.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.0.xsd">
<context:component-scan base-package="com.jadyer"/>

<mvc:annotation-driven/>

<bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">

<property name="prefix" value="/WEB-INF/jsp/"/>

<property name="suffix" value=".jsp"/>

</bean>

</beans>

用来添加用户信息的//WEB-INF//jsp/user/add.jsp

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<%@ page language="java" pageEncoding="UTF-8"%>

<%@ taglib prefix="form" uri="http://www.springframework.org/tags/form"%>

<%-- 这里并没有指定action=""，说明表单是提交给自己的，说白了就是"哪来的回哪儿去 --%>

<form:form method="POST" modelAttribute="user">

username: <form:input path="username"/><br/>

nickname: <form:input path="nickname"/><br/>

password: <form:password path="password"/><br/>

yourmail: <form:input path="email"/><br/>

<input type="submit" value="添加新用户"/>

</form:form>

用来列出所有用户信息的//WEB-INF//jsp/user/list.jsp

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<%@ page language="java" pageEncoding="UTF-8"%>

<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%>

<c:forEach items="${users}" var="user">

${user.value.username}----${user.value.nickname}----${user.value.password}----${user.value.email}

<a href="<%=request.getContextPath()%>/user/${user.value.username}">查看</a>

<a href="<%=request.getContextPath()%>/user/${user.value.username}/update">编辑</a>

<a href="<%=request.getContextPath()%>/user/${user.value.username}/delete">删除</a>

<br/>

</c:forEach>

<br/>

<a href="<%=request.getContextPath()%>/user/add">继续添加用户</a>

用来显示单个用户信息的//WEB-INF//jsp/user/show.jsp

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<%@ page language="java" pageEncoding="UTF-8"%>

${user.username}----${user.nickname}----${user.password}----${user.email}

<br/>

<br/>

<a href="<%=request.getContextPath()%>/user/add">继续添加用户</a>

用来更新单个用户信息的//WEB-INF//jsp/user/update.jsp

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<%@ page language="java" pageEncoding="UTF-8"%>

<%@ taglib prefix="form" uri="http://www.springframework.org/tags/form"%>

<form:form method="POST" modelAttribute="user">

username: <form:input path="username"/><br/>

nickname: <form:input path="nickname"/><br/>

password: <form:password path="password"/><br/>

yourmail: <form:input path="email"/><br/>

<input type="submit" value="更新用户信息"/>

</form:form>

下面是用户的实体类User.java

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package com.jadyer.model;

/**

* User

* @author http://blog.csdn.net/jadyer
* @create May 12, 2012 1:24:43 AM

*/

public class User {

private String username;

private String nickname;

private String password;

private String email;

public User() {}

public User(String username, String nickname, String password, String email) {

this.username = username;

this.nickname = nickname;

this.password = password;

this.email = email;

}

public String getUsername() {

return username;

}

public void setUsername(String username) {

this.username = username;

}

public String getNickname() {

return nickname;

}

public void setNickname(String nickname) {

this.nickname = nickname;

}

public String getPassword() {

return password;

}

public void setPassword(String password) {

this.password = password;

}

public String getEmail() {

return email;

}

public void setEmail(String email) {

this.email = email;

}

}

最后是核心的UserController.java

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package com.jadyer.controller;

import java.util.HashMap;

import java.util.Map;

import org.springframework.stereotype.Controller;

import org.springframework.ui.Model;

import org.springframework.web.bind.annotation.PathVariable;

import org.springframework.web.bind.annotation.RequestMapping;

import org.springframework.web.bind.annotation.RequestMethod;

import com.jadyer.model.User;

/**

* UserController

* @author http://blog.csdn.net/jadyer
* @create May 12, 2012 1:26:21 AM

*/

@Controller

@RequestMapping("/user")

public class UserController {

private final static Map<String,User> users = new HashMap<String,User>();

//模拟数据源,构造初始数据

public UserController(){

users.put("张起灵", new User("张起灵", "闷油瓶", "02200059", "menyouping@yeah.net"));

users.put("李寻欢", new User("李寻欢", "李探花", "08866659", "lixunhuan@gulong.cn"));

users.put("拓拔野", new User("拓拔野", "搜神记", "05577759", "tuobaye@manhuang.cc"));

users.put("孙悟空", new User("孙悟空", "美猴王", "03311159", "sunhouzi@xiyouji.zh"));

}

/**

* 添加新用户

* @see 访问/user/add时，GET请求就执行addUser(Model model)方法，POST请求就执行addUser(User user)方法

*/

@RequestMapping(value="/add", method=RequestMethod.GET)

public String addUser(Model model){

//这里要传给前台一个空对象，否则会报告java.lang.IllegalStateException异常

//异常信息为Neither BindingResult nor plain target object for bean name 'user' available as request attribute

//并且传过去的key值要与前台modelAttribute属性值相同，即model.addAttribute("user", new User());

//我们也可以写成下面这种方式，此时SpringMVC会自动把对象名转换为小写值作为key，即User-->user

model.addAttribute(new User());

return "user/add";

}

@RequestMapping(value="/add", method=RequestMethod.POST)

public String addUser(User user){ //这里参数中的user就应该与add.jsp中的modelAttribute="user"一致了

users.put(user.getUsername(), user);

return "redirect:/user/list";

}

/**

* 列出所有用户信息

*/

@RequestMapping("/list")

public String list(Model model){

model.addAttribute("users", users);

return "user/list";

}

/**

* 查询用户信息

* @see 访问该方法的路径就应该是"/user/具体的用户名"

* @see 这里value="/{username}"的写法，需要格外注意一下，它是一个路径变量，此时用来接收前台的一个资源

* @see 这时value="/{username}"就会到方法参数中找@PathVariable String username，并将路径变量值传给username参数

*/

@RequestMapping(value="/{myname}", method=RequestMethod.GET)

public String show(@PathVariable String myname, Model model){

model.addAttribute(users.get(myname));

return "user/show";

}

/**

* 编辑用户信息

* @see 访问该方法的路径就应该是"/user/具体的用户名/update"

*/

@RequestMapping(value="/{myname}/update", method=RequestMethod.GET)

public String update(@PathVariable String myname, Model model){

model.addAttribute(users.get(myname));

return "user/update";

}

@RequestMapping(value="/{myname}/update", method=RequestMethod.POST)

public String update(User user){

users.put(user.getUsername(), user);

return "redirect:/user/list"; //也可以retun "forward:/user/list",此时浏览器地址栏会有不同

}

/**

* 删除用户信息

*/

@RequestMapping(value="/{myname}/delete", method=RequestMethod.GET)

public String delete(@PathVariable String myname){

users.remove(myname);

return "redirect:/user/list"; //删除完成后显示当前存在的所有用户信息

}

}