13.向页面返回字符串或者对象

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项目目录结构:

  1. WebContent/easyui/: easyui库
  2. WebContent/js/: jquery库
  3. WebContent/json/: easyui的datagrip组件接收的示例json数据

项目依赖包:

Vo: User.java

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package com.course.vo;

public class User {

	private Integer id;
	private String name;
	private Integer age;
	
	public User() {
		super();
	}
	
	public User(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;
	}

	@Override
	public String toString() {
		return "User [id=" + id + ", name=" + name + ", age=" + age + "]";
	}
			
}

Vo: UserInfo.java

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package com.course.vo;

import java.util.Date;

import org.springframework.format.annotation.DateTimeFormat;

import com.fasterxml.jackson.annotation.JsonFormat;

public class UserInfo {

	private Integer id;
	private String name;
	private Integer age;
	private String address;
	// 前端->后端: 时间类型格式转换
	@DateTimeFormat(pattern = "yyyy-MM-dd")
	// 后端->前端: 时间类型格式转换，使用Jackson生成json对象时把时间进行格式化
	@JsonFormat(pattern = "yyyy-MM-dd HH:mm:ss", timezone = "GMT+8")
	private Date time;
	
	public UserInfo() {
		super();
	}

	public UserInfo(Integer id, String name, Integer age, String address, Date time) {
		super();
		this.id = id;
		this.name = name;
		this.age = age;
		this.address = address;
		this.time = time;
	}

	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;
	}

	public String getAddress() {
		return address;
	}

	public void setAddress(String address) {
		this.address = address;
	}

	public Date getTime() {
		return time;
	}

	public void setTime(Date time) {
		this.time = time;
	}

	@Override
	public String toString() {
		return "UserInfo [id=" + id + ", name=" + name + ", age=" + age + ", address=" + address + ", time=" + time
				+ "]";
	}
	
}

DataGripObject.java

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package com.course.util;

import java.util.List;

public class DataGripObject {
	
	private long total;
	private List<?> rows;
	
	public DataGripObject() {
		super();
	}

	public DataGripObject(long total, List<?> rows) {
		super();
		this.total = total;
		this.rows = rows;
	}

	public long getTotal() {
		return total;
	}

	public void setTotal(long total) {
		this.total = total;
	}

	public List<?> getRows() {
		return rows;
	}

	public void setRows(List<?> rows) {
		this.rows = rows;
	}
	
}

UserController.java

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package com.course.controller;

import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.Date;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import javax.servlet.http.HttpServletResponse;

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.alibaba.fastjson.JSONObject;
import com.course.util.DataGripObject;
import com.course.vo.User;
import com.course.vo.UserInfo;

@Controller
@RequestMapping("user")
public class UserController {
	
	static List<String> usernameList = new ArrayList<>();
	
	static {
		usernameList.add("admin");
		usernameList.add("user1");
		usernameList.add("user2");
	}

	// 检查用户名是否存在
	@RequestMapping(value = "checkUserName1", method = RequestMethod.POST)
	public void checkUserName1(String username, HttpServletResponse httpServletResponse) {
		String message = "该用户不存在";
		for (String nameItem : usernameList) {
			if (nameItem.equals(username)) {
				message = "该用户存在";
			}
		}
		try {
			// 处理乱码
			httpServletResponse.setCharacterEncoding("UTF-8");
			httpServletResponse.setContentType("text/html;charset=utf-8");
			
			PrintWriter out = httpServletResponse.getWriter();
			out.write(message);
			out.flush();
			out.close();
		} catch (Exception e) {
			e.printStackTrace();
		}
	}
	
	@RequestMapping(value = "checkUserName2", method = RequestMethod.POST)
	@ResponseBody
	public String checkUserName2(String username) {
		String code = "0";
		for (String nameItem : usernameList) {
			if (nameItem.equals(username)) {
				code = "1";
			}
		}
		return code;
	}
	
	@RequestMapping(value = "getOneUser1", method = RequestMethod.GET, produces = "application/json;charset=utf-8")
	@ResponseBody
	public String getOneUser1() {
		User user = new User();
		user.setId(1);
		user.setName("小明");
		user.setAge(10);
		String json = JSONObject.toJSONString(user);
		return json;
	}
	
	@RequestMapping(value = "getUserList1", method = RequestMethod.GET, produces = "application/json;charset=utf-8")
	@ResponseBody
	public String getUserList1() {
		List<User> userList = new ArrayList<>();
		userList.add(new User(1, "小明", 10));
		userList.add(new User(2, "小李", 11));
		userList.add(new User(3, "小张", 12));
		String json = JSONObject.toJSONString(userList);
		return json;
	}
	
    /*
	 * 1.引入jackson的相关jar包:
	 * 	(1)jackson-annotations-2.8.9.jar
	 * 	(2)jackson-core-2.8.9.jar
	 * 	(3)jackson-databind-2.8.9.jar
	 * 2.springmvc.xml配置文件添加相应的配置
	 * 	<mvc:annotation-driven></mvc:annotation-driven>
	 */
	@RequestMapping(value = "getOneUser2", method = RequestMethod.GET)
	@ResponseBody
	public User getOneUser2() {
		User user = new User();
		user.setId(1);
		user.setName("小明");
		user.setAge(10);
		return user;
	}
	
	@RequestMapping(value = "getUserList2", method = RequestMethod.GET)
	@ResponseBody
	public List<User> getUserList2() {
		List<User> userList = new ArrayList<>();
		userList.add(new User(1, "小明", 10));
		userList.add(new User(2, "小李", 11));
		userList.add(new User(3, "小张", 12));
		return userList;
	}
	
	/*
	 * 返回json对象: Map
	 * @RequestMapping不添加method属性，表示该方法GET和POST请求都接收
	 */
	@RequestMapping(value = "getUserList3")
	@ResponseBody
	public Map<String, Object> getUserList3() {
		Map<String, Object> resultMap = new HashMap<>();
		
		List<UserInfo> userList = new ArrayList<>();
		userList.add(new UserInfo(1, "小明", 10, "address1", new Date()));
		userList.add(new UserInfo(2, "小李", 11, "address2", new Date()));
		userList.add(new UserInfo(3, "小张", 12, "address3", new Date()));
		
		resultMap.put("total", userList.size());
		resultMap.put("rows", userList);
		
		return resultMap;
	}
	
	/*
	 * 返回json对象: Object
	 * @RequestMapping不添加method属性，表示该方法GET和POST请求都接收
	 */
	@RequestMapping(value = "getUserList4")
	@ResponseBody
	public DataGripObject getUserList4() {
		DataGripObject dataGripObject = new DataGripObject();
		
		List<UserInfo> userList = new ArrayList<>();
		userList.add(new UserInfo(1, "user1", 10, "address1", new Date()));
		userList.add(new UserInfo(2, "user2", 11, "address2", new Date()));
		userList.add(new UserInfo(3, "user3", 12, "address3", new Date()));
		
		dataGripObject.setTotal(userList.size());
		dataGripObject.setRows(userList);
		
		return dataGripObject;
	}
	
}

log4j.properties

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# Global logging configuration
log4j.rootLogger=INFO, stdout
# MyBatis logging configuration...
log4j.logger.org.mybatis.example.BlogMapper=TRACE
# Console output...
log4j.appender.stdout=org.apache.log4j.ConsoleAppender
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
log4j.appender.stdout.layout.ConversionPattern=%5p [%t] - %m%n

springmvc.xml

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<?xml version="1.0" encoding="UTF-8"?>

<!-- 头文件 -->
<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"
	xmlns:aop="http://www.springframework.org/schema/aop"
	xmlns:tx="http://www.springframework.org/schema/tx"
	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
        http://www.springframework.org/schema/mvc
		http://www.springframework.org/schema/mvc/spring-mvc.xsd">
		

	<!-- 
		配置控制器
		包扫描
	 -->
	 <context:component-scan base-package="com.course.controller"></context:component-scan>
	
	<!-- 
		合并注解的控制器映射器和控制器适配器的配置
		对控制器映射器和控制器适配器进行加强，如把对象转化为json字符串
	 -->
	<mvc:annotation-driven></mvc:annotation-driven>
	
	<!-- 配置视图解析器 -->
	<bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
		<!-- 配置前缀 -->
		<property name="prefix" value="/WEB-INF/view/"></property>
		<!-- 配置后缀 -->
		<property name="suffix" value=".jsp"></property>
	</bean>
	
</beans>

web.xml

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<?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_3_0.xsd" id="WebApp_ID" version="3.0">
  <display-name>01_springmvc_hello</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>
  
  <!-- 配置SpringMVC编码过滤器 -->
  <filter>
  	<filter-name>encodingFilter</filter-name>
  	<filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class>
  	<!-- 配置编码的值 -->
  	<init-param>
  		<param-name>encoding</param-name>
  		<param-value>UTF-8</param-value>
  	</init-param>
  </filter>
  <filter-mapping>
  	<filter-name>encodingFilter</filter-name>
  	<!-- 
  		方法1: <url-pattern>*.do</url-pattern>
  		<url-pattern>/*</url-pattern>
  	 -->
  	<!-- 指定某个servlet去过滤 -->
  	<servlet-name>springmvc</servlet-name>
  </filter-mapping>
  
  <!-- 配置前端控制器 -->
  <servlet>
  	<servlet-name>springmvc</servlet-name>
  	<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
  	
  	<!-- 加载springmvc.xml -->
  	<init-param>
  		<param-name>contextConfigLocation</param-name>
  		<param-value>classpath:springmvc.xml</param-value>
  	</init-param>
  	
  	<!-- 启动加载 -->
  	<load-on-startup>1</load-on-startup>
  	
  </servlet>
  
  <servlet-mapping>
  	<servlet-name>springmvc</servlet-name>
  	<url-pattern>*.do</url-pattern>
  </servlet-mapping>
  
</web-app>

index.jsp

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<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<body>

	<h2>检查用户名是否存在</h2>
	<p>
		name: <input type="text" name="username" id="username">
		<label id="tip"></label>
	</p>
</body>
<script type="text/javascript" src="js/jquery-3.1.1.min.js"></script>
<script type="text/javascript">
	$(function(){
		$("#username").blur(function(){
			var username = $(this).val();
			var url = "user/checkUserName1.do";
			$.post(url, {"username": username}, function(message) {
				alert(message);
			});
			url = "user/checkUserName2.do";
			$.post(url, {"username": username}, function(code) {
				if (code == "0") {
					$("#tip").html('<font color="blue">该用户不存在</font>');
				} else {
					$("#tip").html('<font color="blue">该用户存在</font>');
				}
			});
		});
		
	});
</script>

</html>

userList.jsp

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<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>
<!DOCTYPE html>
<html>
<head>
    <meta charset="UTF-8">
    <title>Basic CRUD Application - jQuery EasyUI CRUD Demo</title>
    <link rel="stylesheet" type="text/css" href="${pageContext.request.contextPath}/easyui/themes/metro/easyui.css">
    <link rel="stylesheet" type="text/css" href="${pageContext.request.contextPath}/easyui/themes/icon.css">
    <link rel="stylesheet" type="text/css" href="${pageContext.request.contextPath}/easyui/themes/color.css">
    <link rel="stylesheet" type="text/css" href="${pageContext.request.contextPath}/easyui/demo/demo.css">
    <script type="text/javascript" src="${pageContext.request.contextPath}/easyui/jquery.min.js"></script>
    <script type="text/javascript" src="${pageContext.request.contextPath}/easyui/jquery.easyui.min.js"></script>
    <script type="text/javascript" src="${pageContext.request.contextPath}/easyui/locale/easyui-lang-zh_CN.js"></script>
</head>
<body>
    <h2 align="center">所有用户</h2>
    <table id="dg" title="所有用户" iconCls="icon-help" class="easyui-datagrid" style="width:100%;height:550px"
            url="${pageContext.request.contextPath}/user/getUserList4.do"
            toolbar="#toolbar" pagination="true"
            rownumbers="true" fitColumns="true" singleSelect="true">
        <thead>
            <tr>
                <th field="id" width="50" align="center">ID</th>
                <th field="name" width="50">姓名</th>
                <th field="age" width="50">年龄</th>
                <th field="address" width="50">地址</th>
                <th field="time" width="50">生日</th>
            </tr>
        </thead>
    </table>
    <div id="toolbar">
        <a href="javascript:void(0)" class="easyui-linkbutton" iconCls="icon-add" plain="true" onclick="newUser()">添加用户</a>
        <a href="javascript:void(0)" class="easyui-linkbutton" iconCls="icon-edit" plain="true" onclick="editUser()">修改用户</a>
        <a href="javascript:void(0)" class="easyui-linkbutton" iconCls="icon-remove" plain="true" onclick="destroyUser()">删除用户</a>
    </div>
</body>
</html>

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