demo_3

##　　控制器层

需求分析：

访问路径：`/user/reg.do`
请求参数：`username=xx&password=xx&&phone=xx&email=xx`
请求类型：`POST`
响应内容：`JSON`

 在`pom.xml`中添加对`Jackson`的依赖：

     <!-- jackson -->
     <dependency>
         <groupId>com.fasterxml.jackson.core</groupId>
         <artifactId>jackson-databind</artifactId>
         <version>2.9.6</version>
     </dependency>

对于JSON的解释

创建专门用于响应给客户端的JSON数据的类`com.demo.pojo.ResponseResult`

 package com.demo.pojo;

 import java.io.Serializable;

 public class ResponseResult<T> implements Serializable {

     /**
      *
      */
     private static final long serialVersionUID = -8070114279101787255L;

     private static final int STATE_SUCCESS = 1;
     private static final int STATE_ERROR = 0;

     private Integer state;// 成功（1）或失败（0）
     private String message;// 当失败时封装错误信息
     private T data;// 数据

     public ResponseResult() {
         super();
         // TODO Auto-generated constructor stub
     }

     public ResponseResult(Integer state) {
         super();
         this.state = state;
     }

     public ResponseResult(Integer state, String message) {
         super();
         this.state = state;
         this.message = message;
     }

     /**
      * 状态成功
      *
      * @param state 1
      * @param data  数据
      */
     public ResponseResult(Integer state, T data) {
         super();
         this.state = STATE_SUCCESS;
         this.data = data;
     }

     /**
      * 状态失败
      *
      * @param throwable 返回异常
      */
     public ResponseResult(Throwable throwable) {
         super();
         this.state = STATE_ERROR;
         this.message = throwable.getMessage();
     }

     public Integer getState() {
         return state;
     }

     public void setState(Integer state) {
         this.state = state;
     }

     public String getMessage() {
         return message;
     }

     public void setMessage(String message) {
         this.message = message;
     }

     public T getData() {
         return data;
     }

     public void setData(T data) {
         this.data = data;
     }

     public static long getSerialversionuid() {
         return serialVersionUID;
     }

     public static int getStateSuccess() {
         return STATE_SUCCESS;
     }

     public static int getStateError() {
         return STATE_ERROR;
     }

     @Override
     public String toString() {
         return "ResponseResult [state=" + state + ", message=" + message + ", data=" + data + "]";
     }

 }

##　　在IUserService业务层添加登陆接口

 /**
      * 用户登录
      * @param username 用户名
      * @param password 密码
      * @return 成功登录的用户名
      * @throws UsernameNotExistsException
      * @throws PasswordNotMatchException
      */
     User login(String username,String password);

在UserServiceImpl类实现

 public User login(String username, String password) {
         // 根据用户名查询用户信息
         User user = findUserByUsername(username);
         // 判断是否查询到匹配的用户信息
         if (user == null) {
             // 没有则抛出异常，用户名不存在UsernameNotExistsException
             throw new UsernameNotExistsException("尝试登陆的用户名" + username + "不存在！");
         } else {
             // 获取该用户的盐(UUID)
             String salt = user.getUuid();
             // 基于盐，对用于输入的密码（方法的参数）进行加密
             String md5Password = getEncrpytedPassword(password, salt);
             // 判断加密后的密码，与获取的用户信息中的密码是否匹配
             if (user.getPassword().equals(md5Password)) {
                 // 返回查询到的User对象
                 return user;
             } else {
                 // 不匹配则抛出异常，密码错误PasswordNotMatchException
                 throw new PasswordNotMatchException("您输入的用户名或密码不正确");
             }
         }
     }

创建控制器类`com.demo.controller.UserController`，使用`@Controller`注解，并添加`@RequestMapping("/user")`注解。

在这个类中添加`public ResponseResult<Void> handleReg()`方法以处理请求，该方法使用`@RequestMapping(value="/reg.do",method=RequestMethod.POST)`注解，并添加`@ResponseBody`注解。

 package com.demo.controller;

 import javax.servlet.http.HttpSession;

 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.stereotype.Controller;
 import org.springframework.web.bind.annotation.RequestMapping;
 import org.springframework.web.bind.annotation.RequestMethod;
 import org.springframework.web.bind.annotation.ResponseBody;

 import com.demo.pojo.ResponseResult;
 import com.demo.pojo.User;
 import com.demo.service.IUserService;
 import com.demo.service.ex.ServiceException;
 import com.demo.service.ex.UsernameNotExistsException;

 @Controller
 @RequestMapping("/user")
 public class UserController {
     @Autowired
     private IUserService userService;

     // 访问注册页面
     @RequestMapping("/reg.do")
     public String showReg() {
         return "reg";
     }

     // 访问登录页面
     @RequestMapping("login.do")
     public String showLogin() {
         return "login";
     }

     /**
      * 将java数据转换为JSON串类型
      *
      * @param username
      * @param password
      * @param phone
      * @param email
      * @param session
      * @return 执行的数据
      */
     //处理注册信息
     @RequestMapping(value = "/handle_reg.do", method = RequestMethod.POST)
     @ResponseBody
     public ResponseResult<Void> handleReg(String username, String password, String phone, String email,
             HttpSession session) {
         ResponseResult<Void> rr;

         User user = new User();
         user.setUsername(username);
         user.setPassword(password);
         user.setPhone(phone);
         user.setEmail(email);

         try {
             User u = userService.reg(user);
             //绑定信息
             session.setAttribute("uid", u.getUsername());
             rr = new ResponseResult<Void>(ResponseResult.STATE_ERROR);
         } catch (UsernameNotExistsException e) {
             rr = new ResponseResult<Void>(e);
         }
         return rr;
     }
     /**
      *
      * @param username
      * @param password
      * @param session
      * @return
      */
     //处理登录信息
     @RequestMapping(value = "/handle_login.do", method = RequestMethod.POST)
     @ResponseBody
     public ResponseResult<Void> handlerLogin(String username, String password, HttpSession session) {
         ResponseResult<Void> rr;
         try {
             User user = userService.login(username, password);
             //绑定信息
             session.setAttribute("uid", user.getId());
             session.setAttribute("username", user.getUsername());
             rr = new ResponseResult<Void>(ResponseResult.STATE_SUCCESS);
         } catch (ServiceException e) {
             rr = new ResponseResult<Void>(e);
         }
         return rr;
     }
 }

编辑`/web/register.jsp`，测试完毕