springMVC之增删改查(RESTful)，springmvcrestful

一、核心原理

1. 用于发送请求给服务器: /home.htm

2. 请求被DispatchServlet拦截到

3. DispatchServlet通过HandleMapping检查url有没有对应的Controller, 如果有则调用Controller

4. Controller开始执行业务逻辑

5. Controller执行完毕后, 如果返回字符串, 则ViewResolver将字符串转化成相应的视图对象;

如果返回ModelAndView对象, 该对象本身就包含了视图对象信息.

6. DispatchServlet将视图对象中的数据输出给服务器.

7. 服务器将数据输出给客户端.

二、REST风格

1. 查询:
传统:  /user_query?id=123
rest: /user/123
2. 删除:
传统:  /user_delete?id=123
rest: /user/123/delete
3. 更新:
传统:  /user_update?id=123
rest: /user/123/update
4. 列表:
传统:  /user_list
rest: /user/users

三、增删改查

1. 代码结构

2. web.xml 配置DispatchServlet

<?xml version="1.0" encoding="UTF-8"?><web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"          xmlns="http://java.sun.com/xml/ns/javaee"          xsi:schemaLocation="http://java.sun.com/xml/ns/javaee          http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" id="WebApp_ID" version="2.5">           <!-- user需要和配置文件user-servlet.xml名字对应 -->  <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>    <!-- 配置过滤器, 设置编码为UTF-8 -->  <filter><filter-name>CharacterFilter</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>CharacterFilter</filter-name><url-pattern>/*</url-pattern></filter-mapping></web-app>

3. 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:context="http://www.springframework.org/schema/context"xmlns:mvc="http://www.springframework.org/schema/mvc"xsi:schemaLocation="http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-3.1.xsdhttp://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsdhttp://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.1.xsd"><!-- spring扫描的包 --><context:component-scan base-package="com.zdp"></context:component-scan><!-- 使用spring注解 --><mvc:annotation-driven /><!-- 设置返回url前缀和后缀 --><bean class="org.springframework.web.servlet.view.InternalResourceViewResolver"><property name="viewClass" value="org.springframework.web.servlet.view.JstlView"/><property name="prefix" value="/WEB-INF/jsp/"></property><property name="suffix" value=".jsp"></property></bean><!-- 指明静态资源位置 --><mvc:resources location="/WEB-INF/resources/" mapping="/resources/**"/></beans>

4. User.java

/** * 实体类 */public class User {private String username;private String password;public User() {}public User(String username, String password) {this.username = username;this.password = password;}@NotEmpty(message="用户名不能为空")public String getUsername() {return username;}public void setUsername(String username) {this.username = username;}@Size(min=1,max=10,message="密码的长度应该在1和10之间")public String getPassword() {return password;}public void setPassword(String password) {this.password = password;}}

5. UserController.java

@Controller@RequestMapping("/user")public class UserController {// 使用map模拟数据库 private Map<String, User> userMap = new HashMap<String, User>();public UserController() {userMap.put("zhangsan", new User("zhangsan", "123"));userMap.put("lishimin", new User("lishimin", "456"));}// 获取用户列表 // 访问方法: http://localhost/springmvc_user/user/users@RequestMapping(value = "/users", method = RequestMethod.GET)public String list(Model model) {model.addAttribute("users", userMap);return "/user/list";}// 跳转到添加用户页面(get请求)// 访问方法: http://localhost/springmvc_user/user/add@RequestMapping(value = "/add", method = RequestMethod.GET)public String add(@ModelAttribute("user") User user) {return "user/add";}// 具体的添加用户处理方法(post请求) // 注意: BindingResult必须在User之后, 中间不能有其他的参数@RequestMapping(value = "/add", method = RequestMethod.POST)public String add(@Validated User user, BindingResult br) throws IOException { // @Validated: 对User数据进行校验if (br.hasErrors()) {return "user/add"; // 如果有错误, 则直接跳转到add添加用户页面}userMap.put(user.getUsername(), user);return "redirect:/user/users"; // 重定向到用户列表页面}// 查看用户信息// 访问方法: http://localhost/springmvc_user/user/zhangsan@RequestMapping(value="/{username}", method=RequestMethod.GET)public String show(@PathVariable String username, Model model) { // @PathVariable: 路径里面的值作为参数model.addAttribute(userMap.get(username)); return "user/show";}// 跳转到修改用户信息页面// 访问方法: http://localhost/springmvc_user/zhangsan/update@RequestMapping(value="/{username}/update", method=RequestMethod.GET) public String update(@PathVariable String username, Model model) { // @PathVariable: 路径里面的值作为参数model.addAttribute(userMap.get(username)); // 等同: model.addAttribute("user", userMap.get(username));return "user/update";}// 具体的修改用户处理方法(post请求) // 注意: BindingResult必须在User之后, 中间不能有其他的参数@RequestMapping(value="/{username}/update", method=RequestMethod.POST)public String update(@PathVariable String username, @Validated User user, BindingResult br) {if(br.hasErrors()) {return "user/update"; // 如果有错误, 则直接跳转到update修改用户页面}userMap.remove(username);userMap.put(user.getUsername(), user);return "redirect:/user/users";}// 删除用户信息// 访问方法: http://localhost/springmvc_user/zhangsan/delete@RequestMapping(value="/{username}/delete",method=RequestMethod.GET)public String delete(@PathVariable String username) {userMap.remove(username);return "redirect:/user/users";}}

6. jsp pages

① list.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%><%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %><!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"><html><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8"><title>用户列表 </title><!-- 引入静态文件, 需要在user-servlet.xml配置映射关系 --><link rel="stylesheet" href="<%=request.getContextPath()%>/resources/css/main.css" type="text/css"></head><body><a href="add">添加</a><br/><c:forEach items="${users}" var="usermap"><a href="${usermap.value.username}">${usermap.value.username}</a>-- <a href="${usermap.value.username}/update">修改</a>-- <a href="${usermap.value.username}/delete">删除</a><br/></c:forEach></body></html>

② add.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%><%@ taglib prefix="sf" uri="http://www.springframework.org/tags/form" %><!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"><html><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8"><title>添加用户</title></head><body><!-- 如没写action, 也会提交给add(匹配文件名) --><sf:form method="post" modelAttribute="user" action="add">Username:<sf:input path="username"/><sf:errors path="username"/><br/>Password:<sf:password path="password"/><sf:errors path="password"/><br/><input type="submit" value="添加用户"/></sf:form></body></html>

③ show.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%><%@ taglib prefix="sf" uri="http://www.springframework.org/tags/form" %><!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"><html><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8"><title>用户详细信息</title></head><body>Username:${user.username}<br/>Password:${user.password}<br/></body></html>

④ update.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%><%@ taglib prefix="sf" uri="http://www.springframework.org/tags/form" %><!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"><html><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8"><title>修改用户</title></head><body><!-- 如没写action, 也会提交给update(匹配文件名) --><sf:form method="post" modelAttribute="user" action="update">Username:<sf:input path="username"/><sf:errors path="username"/><br/>Password:<sf:password path="password"/><sf:errors path="password"/><br/><input type="submit" value="修改用户"/></sf:form></body></html>