SpringMVC表单的处理

一.获取请求参数
1.通过HttpRequestServlet获取请求参数
public String handlerRegister(HttpServletRequest request) {
    //获取请求参数
    String username = request.getParameter("username");
    return null;
}

2.以上方式要求参数的名称与前端页面的表单中的名称保持一致！如果参数名与表单中使用的名称不同，可以使用 @RequestParam 注解：
public String handlerRegister(@RequestParam("password") String pwd,String username) {
    System.out.println("username="+username);
    System.out.println("password="+pwd);
    return null;
}


3.通过Java Bean直接接收所有请求参数的值
设计一个Java Bean包含所有的请求参数，并且在Java Bean中的属性名与前端页面的表单中使用的名称保持一致，

@Component
public class User {
    private String username;
    private String password;
    private int salary;
    // ... Set/Get方法 ...
}


public String handleRegister(User user) {
    // 直接使用参数即可，这些参数已经被赋值
}


二.使用ModelAndView
public ModelAndView handlerRegister(HttpServletRequest request, User user,
ModelMap data,HttpSession session) {
    ModelAndView mav = new ModelAndView();
    mav.setViewName("user_register_info");
}

1.通过request封装转发
request.setAttribute("name", user.getUsername());

2.使用ModelAndView
mav.getModel().put("pwd", user.getPassword());

3.使用ModelMap
data.addAttribute("salary", user.getSalary());

4.使用session
session.setAttribute("name",user.getUsername());

5.常见使用情况
（1）使用Session保存数据
    a)当前用户的身份标识 
    b)高频率使用的用户数据
（2）仅会在此次请求时显示的数据，使用ModelMap
    a)密码，金额等不常显示数据
    b)异常的错误提示信息


三.案例目标：注册
1.界面
user_register_form.jsp：注册的表单
user_register_success.jsp：注册成功（暂定）
error.jsp：操作失败，用于提交操作失败的信息


2.用户信息
Integer id
String username
String password
Integer salary


3.数据库与数据表
数据库：springmvc
数据表：
create table user (
    id int auto_increment,
    username varchar(16) not null unique,
    password varchar(16) not null,
    salary int,
    primary key(id)
);


四.实例
1.resources下的spring配置文件和数据库信息配置文件

applicationContext.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:jdbc="http://www.springframework.org/schema/jdbc" xmlns:jee="http://www.springframework.org/schema/jee"xmlns:tx="http://www.springframework.org/schema/tx" xmlns:aop="http://www.springframework.org/schema/aop"xmlns:mvc="http://www.springframework.org/schema/mvc" xmlns:util="http://www.springframework.org/schema/util"xmlns:jpa="http://www.springframework.org/schema/data/jpa"xsi:schemaLocation="        http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.2.xsd        http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.2.xsd        http://www.springframework.org/schema/jdbc http://www.springframework.org/schema/jdbc/spring-jdbc-3.2.xsd        http://www.springframework.org/schema/jee http://www.springframework.org/schema/jee/spring-jee-3.2.xsd        http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-3.2.xsd        http://www.springframework.org/schema/data/jpa http://www.springframework.org/schema/data/jpa/spring-jpa-1.3.xsd        http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-3.2.xsd        http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-3.2.xsd        http://www.springframework.org/schema/util http://www.springframework.org/schema/util/spring-util-3.2.xsd">            <context:component-scan base-package="cn.tedu.spring"/><bean class="org.springframework.web.servlet.view.InternalResourceViewResolver"><property name="prefix" value="/WEB-INF/jsp/"/><property name="suffix" value=".jsp"/></bean>        <util:properties id="dbConfig" location="classpath:db.properties"></util:properties><!-- 配置DBCP所需的Bean --><bean id="ds" class="org.apache.commons.dbcp.BasicDataSource"><property name="driverClassName" value="#{dbConfig.driver}"></property><property name="url" value="#{dbConfig.url}"></property><property name="username" value="#{dbConfig.username}"></property><property name="password" value="#{dbConfig.password}"></property><property name="initialSize" value="#{dbConfig.initsize}"></property><property name="maxActive" value="#{dbConfig.maxsize}"></property></bean></beans>

db.properties

driver=com.mysql.jdbc.Driverurl=jdbc:mysql://localhost:3306/springmvcusername=rootpasswordinitsize=1maxsize=5

2.web.xml配置文件

<?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" version="2.5">  <display-name>DAY05-SpringMVC-Sample</display-name>  <welcome-file-list>    <welcome-file>index.html</welcome-file>    <welcome-file>index.htm</welcome-file>    <welcome-file>index.jsp</welcome-file><welcome-file>default.html</welcome-file><welcome-file>default.htm</welcome-file><welcome-file>default.jsp</welcome-file>  </welcome-file-list> <servlet> <servlet-name>SpringMVC</servlet-name> <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class> <init-param> <param-name>contextConfigLocation</param-name> <param-value>classpath:applicationContext.xml</param-value> </init-param> <load-on-startup>1</load-on-startup> </servlet> <servlet-mapping> <servlet-name>SpringMVC</servlet-name> <url-pattern>*.do</url-pattern> </servlet-mapping>  <filter> <filter-name>CharacterEncodingFilter</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>CharacterEncodingFilter</filter-name> <url-pattern>/*</url-pattern> </filter-mapping>  <!-- 只适用与Post请求 --></web-app>

3.WEB-INF下jsp文件下三个文件

user_register_form.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"    pageEncoding="UTF-8"%><!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>注册</title><style type="text/css">tr{padding:5px;line-height:30px;font-size:16px;}input{line-height:20px;padding:7px;background-color:#eee;border:0;}.user{padding:7px;line-height:20px;}</style></head><body><h1>用户注册</h1><form action="handlerRegister.do" method="post"><table><tr><td class="user">用户名</td><td><input type="text" name="username" placeholder="username"/></td></tr><tr><td class="user">密码</td><td><input type="password" name="password" placeholder="password"/></td></tr><tr><td class="user">月薪</td><td><input type="text" name="salary" placeholder="salary"/></td></tr><tr><td><input style="background-color:#bbb;color:#f6a;width:45px;" type="submit" value="提交"/></td></tr></table></form></body></html>

user_register_success.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"    pageEncoding="UTF-8"%><!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>注册成功</title><style type="text/css">tr{padding:5px;line-height:30px;font-size:16px;}input{line-height:20px;padding:7px;background-color:#eee;border:0;}.user{padding:7px;line-height:20px;}</style></head><body><h3>注册成功</h3><h4>您的用户名：${username }，用户ID：${uid},密码：${pwd }，月薪：${salary }。</h4></body></html>

error.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"    pageEncoding="UTF-8"%><!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>注册成功</title><style type="text/css">tr{padding:5px;line-height:30px;font-size:16px;}input{line-height:20px;padding:7px;background-color:#eee;border:0;}.user{padding:7px;line-height:20px;}</style></head><body><h3>注册失败</h3><h4>${errorMessage}</h4></body></html>

4.自定义异常类

package cn.tedu.spring.exception;public class UsernameAlreadyExistsException extends RuntimeException{private static final long serialVersionUID = -7585802889324479550L;public UsernameAlreadyExistsException() {super();}public UsernameAlreadyExistsException(String message) {super(message);}}

5.数据库关闭连接类

package cn.tedu.spring.util;import java.sql.Connection;import java.sql.ResultSet;import java.sql.SQLException;import java.sql.Statement;public class DBUtil {public static void close(Connection conn, Statement stmt, ResultSet rs) {close(conn);close(stmt);close(rs);}public static void close(Connection conn) {if (conn != null) {try {conn.close();} catch (SQLException e) {e.printStackTrace();}}}public static void close(Statement stmt) {if (stmt != null) {try {stmt.close();} catch (SQLException e) {e.printStackTrace();}}}public static void close(ResultSet rs) {if (rs != null) {try {rs.close();} catch (SQLException e) {e.printStackTrace();}}}}

6.JavaBean类

package cn.tedu.spring.bean;public class User {private Integer id;private String username;private String password;private Integer salary;public Integer getId() {return id;}public void setId(Integer id) {this.id = id;}public String getUsername() {return username;}public void setUsername(String username) {this.username = username;}public String getPassword() {return password;}public void setPassword(String password) {this.password = password;}public Integer getSalary() {return salary;}public void setSalary(Integer salary) {this.salary = salary;}@Overridepublic String toString() {return "User [id=" + id + ", username=" + username + ", password=" + password + ", salary=" + salary + "]";}}

7.Dao类

package cn.tedu.spring.dao;import cn.tedu.spring.bean.User;public interface IUserDao {/** * 增加用户数据 * @param user 被增加的数据 * @return 增加的数据在数据库中的ID */Integer insert(User user);/** * 根据用户名查找用户信息 * @param username 用户信息 * @return 与用户名匹配的用户数据，如果没有匹配 *   的数据，则返回null */User findUserByUsername(String username);}

package cn.tedu.spring.dao;import java.sql.Connection;import java.sql.PreparedStatement;import java.sql.ResultSet;import java.sql.SQLException;import java.sql.Statement;import javax.annotation.Resource;import org.apache.commons.dbcp.BasicDataSource;import org.springframework.stereotype.Component;import cn.tedu.spring.bean.User;import cn.tedu.spring.util.DBUtil;@Component("userDao")public class UserDaoImpl implements IUserDao {@Resource(name="ds")private BasicDataSource ds;public Integer insert(User user) {//1. 声明变量// -- Connection// -- PreparedStatement// -- ResultSet// -- String sql// -- 返回值Connection conn = null;PreparedStatement pstmt = null;ResultSet rs = null;String sql = "insert into user (username, password, salary) values (?,?,?)";Integer id = -1;//2. 为这些变量赋值// -- sql// -- Connection// -- PreparedStatement// -- ... ...//3. 为PreparedStatement配置?的值try {conn=ds.getConnection();pstmt=conn.prepareStatement(sql,Statement.RETURN_GENERATED_KEYS);pstmt.setString(1, user.getUsername());pstmt.setString(2, user.getPassword());pstmt.setInt(3, user.getSalary());//4. 执行int affectedRows = pstmt.executeUpdate();//5. 处理结果if (affectedRows > 0) {rs = pstmt.getGeneratedKeys();if (rs.next()) {id = rs.getInt(1);}}} catch (SQLException e) {e.printStackTrace();}finally {// 6. 释放资源DBUtil.close(conn, pstmt, rs);}// 7. 返回return id;}public User findUserByUsername(String username) {// 1. 声明变量：// -- Connection// -- PreparedStatement// -- ResultSet// -- String sql// -- 返回值Connection conn = null;PreparedStatement pstmt = null;ResultSet rs = null;String sql = "select id, username, password, salary from user where username=?";User user = null;try {// 2. 为这些变量赋值// -- Connection// -- PreparedStatement// -- ... ...conn = ds.getConnection();pstmt = conn.prepareStatement(sql);// 3. 为PreparedStatement配置?的值pstmt.setString(1, username);// 4. 执行rs = pstmt.executeQuery();// 5. 处理结果if (rs.next()) {user = new User();user.setId(rs.getInt(1));user.setUsername(rs.getString(2));user.setPassword(rs.getString(3));user.setSalary(rs.getInt(4));}} catch (SQLException e) {e.printStackTrace();} finally {// 6. 释放资源DBUtil.close(conn, pstmt, rs);}// 7. 返回return user;}}

8.service类

package cn.tedu.spring.service;import cn.tedu.spring.bean.User;public interface IUserService {/** * 注册  * @param user 需要注册的用户信息 * @return 成功注册的用户的ID，如果注册失败，返回-1 * @throws UsernameAlreadyExistsException */Integer reg(User user);}

package cn.tedu.spring.service;import javax.annotation.Resource;import org.springframework.stereotype.Component;import cn.tedu.spring.bean.User;import cn.tedu.spring.dao.IUserDao;import cn.tedu.spring.exception.UsernameAlreadyExistsException;@Component("userService")public class UserServiceImpl implements IUserService{@Resource(name="userDao")private IUserDao userDao;public Integer reg(User user) {//根据需要增加的用户的用户名去查找数据库User check = userDao.findUserByUsername(user.getUsername());//如果没有找到数据，则意味着用户名没有被注册//则允许注册//如果找到数据，则意味着用户名已经被注册//则不允许注册if(check==null) {return userDao.insert(user);}else {throw new UsernameAlreadyExistsException("注册失败！用户名已经被注册！");}}}

9.控制器类

package cn.tedu.spring.controller;import javax.annotation.Resource;import javax.servlet.http.HttpSession;import org.springframework.stereotype.Controller;import org.springframework.ui.ModelMap;import org.springframework.web.bind.annotation.RequestMapping;import cn.tedu.spring.bean.User;import cn.tedu.spring.exception.UsernameAlreadyExistsException;import cn.tedu.spring.service.IUserService;@Controller@RequestMapping("/user")public class UserController {@Resource(name="userService")private IUserService userService;@RequestMapping("/reg.do")public String showRegisterForm() {return "user_register_form";}@RequestMapping("/handlerRegister.do")public String handlerRegisterForm(User user,ModelMap data,HttpSession session) {//由于需要调用的Service中的方法是可能抛出异常的，//所以，以下代码使用try_catch语法try {//尝试调用注册功能Integer uid = userService.reg(user);//使用Session保存数据// a)当前用户的身份标识 // b)高频率使用的用户数据session.setAttribute("uid", uid);session.setAttribute("username", user.getUsername());//仅会在此次请求时显示的数据，使用ModelMapdata.addAttribute("pwd", user.getPassword());data.addAttribute("salary", user.getSalary());//如果执行以上方法时没有抛出异常//则注册是成功的，则转发到“注册成功”的页面return "user_register_success";} catch (UsernameAlreadyExistsException e) {//跟踪异常信息e.printStackTrace();//将异常的错误提示封装并转发data.addAttribute("errorMessage",e.getMessage());//转发return "error";}catch (Exception e) {//跟踪异常信息e.printStackTrace();//将异常的错误提示封装并转发data.addAttribute("errorMessage","未知错误！请联系系统管理员！");//转发return "error";}}}

10.测试类，过程中有需要可以写

package cn.tedu.test;import java.sql.SQLException;import org.apache.commons.dbcp.BasicDataSource;import org.springframework.context.support.AbstractApplicationContext;import org.springframework.context.support.ClassPathXmlApplicationContext;import org.springframework.web.filter.CharacterEncodingFilter;import com.mysql.jdbc.Driver;import cn.tedu.spring.bean.User;import cn.tedu.spring.dao.IUserDao;import cn.tedu.spring.service.IUserService;@SuppressWarnings("unused")public class Test {@SuppressWarnings("null")public void test() {Driver driver;CharacterEncodingFilter filter;BasicDataSource source = null;source.setDriverClassName(null);source.setUrl(null);source.setUsername(null);source.setPassword(null);source.getInitialSize();source.getMaxActive();}@org.junit.Testpublic void testDBCP() {String file = "applicationContext.xml";AbstractApplicationContext context = new ClassPathXmlApplicationContext(file);BasicDataSource ds = context.getBean("ds",BasicDataSource.class);System.out.println(ds.getDriverClassName());System.out.println(ds.getUrl());System.out.println(ds.getUsername());System.out.println(ds.getPassword());System.out.println(ds.getInitialSize());System.out.println(ds.getMaxActive());try {System.out.println(ds.getConnection());} catch (SQLException e) {e.printStackTrace();}context.close();}@org.junit.Testpublic void testInsert() {String file = "applicationContext.xml";AbstractApplicationContext context = new ClassPathXmlApplicationContext(file);User user = new User();user.setUsername("admin");user.setPassword("admin888");user.setSalary(8000);IUserDao userDao = context.getBean("userDao",IUserDao.class);Integer id = userDao.insert(user);System.out.println("id=" + id);context.close();}@org.junit.Testpublic void testFindUser() {String file = "applicationContext.xml";AbstractApplicationContext ctx = new ClassPathXmlApplicationContext(file);IUserDao userDao = ctx.getBean("userDao", IUserDao.class);User user = userDao.findUserByUsername("admin");System.out.println(user);ctx.close();}@org.junit.Testpublic void testReg() {String file = "applicationContext.xml";AbstractApplicationContext context = new ClassPathXmlApplicationContext(file);User user = new User();user.setUsername("admin");user.setPassword("admin888");user.setSalary(8000);IUserService userService = context.getBean("userService",IUserService.class);Integer id = userService.reg(user);System.out.println("id=" + id);context.close();}}