SpringMVC工作原理（含案例圖解）
阿新 • • 發佈：2019-02-17
SpimgMVC工作原理
第1步：瀏覽器傳送指定的請求都會交給DispatcherServlet,他會委託其他模組進行真正的業務和資料處理
第2步：DispatcherServlet會查詢到HandleMapping,根據瀏覽器的請求找到對應的Controller，並將請求交給目標Controller
第3步：目標Controller處理完業務後，返回一個ModelAndView給DispatcherServlet
第4步：DispatcherServlet通過ViewResolver檢視解析器找到對應的檢視物件View
第5步：檢視物件View負責渲染，並返回到瀏覽器
案例分析
下面通過案例圖解的方式理解下上面的工作原理
第1步-瀏覽器請求
第2、3步-找到對應Controller
第4、5步-解析檢視物件，返回瀏覽器
瀏覽器結果
原始碼
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" springmvc-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:aop="http://www.springframework.org/schema/aop"
xmlns:context="http://www.springframework.org/schema/context" xmlns:tx="http://www.springframework.org/schema/tx"
xmlns:mvc="http://www.springframework.org/schema/mvc"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans.xsd
http://www.springframework.org/schema/aop
http://www.springframework.org/schema/aop/spring-aop.xsd
http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context.xsd
http://www.springframework.org/schema/tx
http://www.springframework.org/schema/tx/spring-tx.xsd
http://www.springframework.org/schema/mvc
http://www.springframework.org/schema/mvc/spring-mvc.xsd">
<!-- springmvc註解驅動 -->
<mvc:annotation-driven></mvc:annotation-driven>
<!-- 開啟註解掃描 -->
<context:component-scan base-package="cn.itcast.controller"></context:component-scan>
<!-- 配置試圖解析器
prefix:指定試圖所在目錄
suffix:指定檢視的字尾名
例如：prifex="/WEB-INF/jsp/",suffix=".jsp",當viewname="test"時，跳轉到/WEB-INF/jsp/test.jsp頁面
-->
<bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
<property name="prefix" value="/WEB-INF/jsp/"></property>
<property name="suffix" value=".jsp"></property>
</bean>
</beans>
UserControll類
@Controller
@RequestMapping("user")
public class UserController {
@RequestMapping("findAllUsers")
public ModelAndView findAllUsers() {
ModelAndView mv = new ModelAndView();
ArrayList<User> users = new ArrayList<User>();
for (int i = 0; i < 5; i++) {
User user = new User();
user.setUsername("zs" + i);
user.setAge(20 + i);
user.setIncome(16000.0+i*100);
user.setIsMarry(false);
user.setHobby(new String[] { "籃球"+i, "足球"+i });
users.add(user);
}
mv.addObject("users", users);
mv.setViewName("users");
return mv;
}
}實體類
public class User implements Serializable {
/**
*
*/
private static final long serialVersionUID = 1L;
private String username;
private Integer age;
private Boolean isMarry;
private Double income;
private String[] hobby;
public String getUsername() {
return username;
}
public void setUsername(String username) {
this.username = username;
}
public Integer getAge() {
return age;
}
public void setAge(Integer age) {
this.age = age;
}
public Boolean getIsMarry() {
return isMarry;
}
public void setIsMarry(Boolean isMarry) {
this.isMarry = isMarry;
}
public Double getIncome() {
return income;
}
public void setIncome(Double income) {
this.income = income;
}
public String[] getHobby() {
return hobby;
}
public void setHobby(String[] hobby) {
this.hobby = hobby;
}
@Override
public String toString() {
return "User [username=" + username + ", age=" + age + ", isMarry=" + isMarry + ", income=" + income
+ ", hobby=" + Arrays.toString(hobby) + "]";
}
}
JSP頁面
<%@ 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>
<link rel="stylesheet" type="text/css" href="/css/user.css" />
</head>
<body>
<table id="customers">
<tr>
<th>使用者名稱</th>
<th>年齡</th>
<th>收入</th>
<th>婚姻狀態</th>
<th>興趣愛好</th>
</tr>
<!-- 遍歷後臺傳遞的集合資料 -->
<c:forEach items="${users}" var="user">
<tr>
<td>${user.username}</td>
<td>${user.age}</td>
<td>${user.income}</td>
<!-- 判婚姻狀態 -->
<td><c:choose>
<c:when test="${user.isMarry}">已婚</c:when>
<c:otherwise>未婚</c:otherwise>
</c:choose>
</td>
<td>
<!-- 再次遍歷使用者愛好 -->
<c:forEach items="${user.hobby}" var="hobby" varStatus="status">
${hobby}
<!-- 如果不是最後一個愛好，則加上逗號，否則就不加 -->
<c:if test="${!status.last}">,</c:if>
</c:forEach>
</td>
</tr>
</c:forEach>
</table>
</body>
</html>