第二章 Spring MVC 增改查实例

本章是个小示例，使用spring mvc 模拟student对象的增删改查


一、spring mvc 注解：


1、@Controller 声明控制器

@Controller
public class StudentController {
    //....
}

2、@RequestMapping 请求映射/请求路径

@RequestMapping("/student")
public class StudentController {
    //访问路径，项目路径/student


    @RequestMapping("/list")
    public ModelAndView list() {
        //访问路径，项目路径/student/list
    }


}

3、@RequestParam 请求参数

@RequestMapping("/preSave")
public ModelAndView preSave(@RequestParam(value = "id", required = false) String id){
    //参数id
}

@RequestMapping("/save")
public ModelAndView save(Student student){
    //默认缺省参数，可传对象
}

4、ModelAndView 返回模型和视图

@RequestMapping("/delete")
public ModelAndView delete(Student student) {
	studentMap.remove(student.getId());
	ModelAndView mav = new ModelAndView();
	mav.addObject("studentList", studentMap);
	mav.setViewName("student/list");
	return mav;
}

二、spring 中文编码过滤器，添加在web.xml；

	<filter>
		<filter-name>encodingFilter</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>
		<init-param>
			<param-name>forceEncoding</param-name>
			<param-value>true</param-value>
		</init-param>
	</filter>
	<filter-mapping>
		<filter-name>encodingFilter</filter-name>
		<url-pattern>/*</url-pattern>
	</filter-mapping>

三、jsp 遍历HashMap中的对象，并取对象中的属性

	<c:forEach var="student" items="${studentList }">
	<tr>
		<td>${student.value.id }</td>
		<td>${student.value.name }</td>
		<td>${student.value.age }</td>
		<td>
			<a href="${pageContext.request.contextPath}/student/preSave.do?id=${student.value.id}">修改</a>
			&nbsp;&nbsp;&nbsp;&nbsp;
			<a href="${pageContext.request.contextPath}/student/delete.do?id=${student.value.id}">删除</a>
		</td>
	</tr>
	</c:forEach>

四、ModelAndView返回模型和视图：

	/**
	 * 跳转修改或新增页面
	 * 
	 * @param id
	 * @return
	 */
	@RequestMapping("/preSave")
	public ModelAndView preSave(
			@RequestParam(value = "id", required = false) String id) {
		ModelAndView mav = new ModelAndView();
		if (id != null) {
			mav.addObject("student", studentMap.get(Integer.parseInt(id)));
			mav.setViewName("student/update");
		} else {
			mav.setViewName("student/add");
		}
		return mav;
	}

五、SpringMVC对象属性自动封装

	/**
	 * 保存，有则修改，没有则
	 * 
	 * @param student
	 * @return
	 */
	@RequestMapping("/save")
	public String save(Student student) {
		if (student.getId() == null) {
			// 新增id自动增1
			identityId += 1;
			student.setId(identityId);
			studentMap.put(student.getId(), student);
		} else {
			// 修改则直接覆盖原有数据
			studentMap.put(student.getId(), student);
		}
		//转发
		return "redirect:/student/list.do";
		//重定向
		// return "redirect:/student/list.do";
	}

六、内部重定向与转发：

	/**
	 * 删除
	 * 
	 * @param student
	 * @return
	 */
	@RequestMapping("/delete")
	public String delete(@RequestParam("id") Integer id) {
		studentMap.remove(id);
		//转发
		return "redirect:/student/list.do";
		//重定向
		// return "redirect:/student/list.do";
	}

项目源码：


web.xml

<?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">
	<!-- 中文编码过滤器 -->
	<filter>
		<filter-name>encodingFilter</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>
		<init-param>
			<param-name>forceEncoding</param-name>
			<param-value>true</param-value>
		</init-param>
	</filter>
	<filter-mapping>
		<filter-name>encodingFilter</filter-name>
		<url-pattern>/*</url-pattern>
	</filter-mapping>
	<display-name>SpringMvc02</display-name>
	<welcome-file-list>
		<welcome-file>index.jsp</welcome-file>
	</welcome-file-list>
	<!-- 定义spring mvc -->
	<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:spring-mvc.xml</param-value>
		</init-param>
	</servlet>
	<!-- controller访问后缀 -->
	<servlet-mapping>
		<servlet-name>springmvc</servlet-name>
		<url-pattern>*.do</url-pattern>
	</servlet-mapping>
</web-app>

spring-mvc.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:p="http://www.springframework.org/schema/p"
    xmlns:context="http://www.springframework.org/schema/context"
    xsi:schemaLocation="
        http://www.springframework.org/schema/beans
        http://www.springframework.org/schema/beans/spring-beans.xsd
        http://www.springframework.org/schema/context
        http://www.springframework.org/schema/context/spring-context.xsd">

	<!-- 使用注解的包，包括子集 -->
    <context:component-scan base-package="com.fx"/>

    <!-- 视图解析器 -->
	<bean id="viewResolver"
		class="org.springframework.web.servlet.view.InternalResourceViewResolver">
		<property name="prefix" value="/WEB-INF/jsp/" />
		<property name="suffix" value=".jsp"></property>
	</bean>

</beans>

Student.java

package com.fx.model;

public class Student {

	private Integer id;
	private String name;
	private Integer age;

	public Student() {
		super();
	}

	public Student(Integer id, String name, Integer age) {
		super();
		this.id = id;
		this.name = name;
		this.age = age;
	}

	public Integer getId() {
		return id;
	}

	public void setId(Integer id) {
		this.id = id;
	}

	public String getName() {
		return name;
	}

	public void setName(String name) {
		this.name = name;
	}

	public Integer getAge() {
		return age;
	}

	public void setAge(Integer age) {
		this.age = age;
	}

}

StudentController.java

package com.fx.controller;

import java.util.HashMap;
import java.util.Map;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.servlet.ModelAndView;

import com.fx.model.Student;

/**
 * Controller：定义Controller控制器 RequestMapping：设置请求路径
 * 
 * @author fx
 *
 */
@Controller
@RequestMapping("/student")
public class StudentController {

	private Integer identityId = 3;

	private static Map<Integer, Student> studentMap = new HashMap<Integer, Student>();

	static {
		studentMap.put(1, new Student(1, "张三", 11));
		studentMap.put(2, new Student(2, "李四", 12));
		studentMap.put(3, new Student(3, "王五", 13));
	}

	/**
	 * 查询列表
	 * 
	 * @return
	 */
	@RequestMapping("/list")
	public ModelAndView list() {
		ModelAndView mav = new ModelAndView();
		mav.addObject("studentList", studentMap);
		mav.setViewName("student/list");
		return mav;
	}

	/**
	 * 跳转修改或新增页面
	 * 
	 * @param id
	 * @return
	 */
	@RequestMapping("/preSave")
	public ModelAndView preSave(
			@RequestParam(value = "id", required = false) String id) {
		ModelAndView mav = new ModelAndView();
		if (id != null) {
			mav.addObject("student", studentMap.get(Integer.parseInt(id)));
			mav.setViewName("student/update");
		} else {
			mav.setViewName("student/add");
		}
		return mav;
	}

	/**
	 * 保存，有则修改，没有则
	 * 
	 * @param student
	 * @return
	 */
	@RequestMapping("/save")
	public String save(Student student) {
		if (student.getId() == null) {
			// 新增id自动增1
			identityId += 1;
			student.setId(identityId);
			studentMap.put(student.getId(), student);
		} else {
			// 修改则直接覆盖原有数据
			studentMap.put(student.getId(), student);
		}
		//转发
		return "redirect:/student/list.do";
		//重定向
		// return "redirect:/student/list.do";
	}

	/**
	 * 删除
	 * 
	 * @param student
	 * @return
	 */
	@RequestMapping("/delete")
	public String delete(@RequestParam("id") Integer id) {
		studentMap.remove(id);
		//转发
		return "redirect:/student/list.do";
		//重定向
		// return "redirect:/student/list.do";
	}
}

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>Insert title here</title>
</head>
<body>
<a href="${pageContext.request.contextPath}/student/preSave.do">添加学生</a>
<table>
	<tr>
		<th>编号</th>
		<th>姓名</th>
		<th>年龄</th>
		<th>操作</th>	
	</tr>
	<c:forEach var="student" items="${studentList }">
	<tr>
		<td>${student.value.id }</td>
		<td>${student.value.name }</td>
		<td>${student.value.age }</td>
		<td>
			<a href="${pageContext.request.contextPath}/student/preSave.do?id=${student.value.id}">修改</a>
			&nbsp;&nbsp;&nbsp;&nbsp;
			<a href="${pageContext.request.contextPath}/student/delete.do?id=${student.value.id}">删除</a>
		</td>
	</tr>
	</c:forEach>
</table>

</body>
</html>

add.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>Insert title here</title>
</head>
<body>
<form action="save.do" method="post">
<table>
	<tr>
		<th colspan="2">学生添加</th>
	</tr>
	<tr>
		<td>姓名</td>
		<td><input type="text" name="name"/></td>
	</tr>
	<tr>
		<td>年龄</td>
		<td><input type="text" name="age"/></td>
	</tr>
	<tr>
		<td colspan="2">
			<input type="submit" value="提交"/>
		</td>
	</tr>
</table>
</form>
</body>
</html>

update.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>Insert title here</title>
</head>
<body>
<form action="save.do" method="post">
<table>
	<tr>
		<th colspan="2">学生修改</th>
	</tr>
	<tr>
		<td>姓名</td>
		<td><input type="text" name="name" value="${student.name }"/></td>
	</tr>
	<tr>
		<td>年龄</td>
		<td><input type="text" name="age" value="${student.age }"/></td>
	</tr>
	<tr>
		<td colspan="2">
			<input type="hidden" name="id" value="${student.id }"/>
			<input type="submit" value="提交"/>
		</td>
	</tr>
</table>
</form>
</body>
</html>

访问路径：
http://localhost:8080/SpringMvc02/student/list.do