SpringMVC教程/实例(三)：java SpringMVC之REST实现简单的增删改查CRUD

 

这是一个WebProject，用到的是spring-framework-3.1.1.RELEASE
首先是web.xml

<?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        }    }