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（最终应用访问地址为http://IP:port/contextPath/user/add）

<?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

<?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

<%@ 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

<%@ 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

<%@ 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

<%@ 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

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

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", "[e-mail]"));          users.put("李寻欢", new User("李寻欢", "李探花", "08866659", "[e-mail]"));          users.put("拓拔野", new User("拓拔野", "搜神记", "05577759", "[e-mail]"));          users.put("孙悟空", new User("孙悟空", "美猴王", "03311159", "[e-mail]"));      }            /**      * 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      }  }