深入分析springmvc中的处理器映射器和适配器

ゞ浴缸里的玫瑰 2022-05-23 01:50 192阅读 0赞

**前言  
   **随着springmvc的注解功能使用，springmvc已经逐渐取代struts2成为目前比较主流的mvc框架，在springmvc中除了核心控制器DispatcherServlet这个核心组件之外，还有在springmvc中的处理器映射器和适配器，这两个组件在springmvc整个的运行流程之中扮演一个很重要的角色，至于映射器和适配器这两个组件他们的功能，我们可以这样理解，映射器主要是跟我们在浏览器上输入的url来映射对应的Handle,具体的映射规则需要根据使用哪一个映射器来决定，而适配器主要是决定调用哪个Handler来实现具体的业务逻辑，随着注解的发展，映射器和适配器的使用也越来越方便，但是熟悉这两个组件的底层实现，对我们在日常开发和对springmvc的理解也是有帮助的，下面我们一起来看看非注解的映射器和适配器具体实现案例。

**1.目录**

![70][]

**2.jar包：**

![70 1][]

**3.web.xml配置文件：**

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

<web-app version=*"2.5"*

xmlns=*"http://java.sun.com/xml/ns/javaee"*

xmlns:xsi=*"http://www.w3.org/2001/XMLSchema-instance"*

xsi:schemaLocation=*"http://java.sun.com/xml/ns/javaee*

*http://java.sun.com/xml/ns/javaee/web-app\_2\_5.xsd"*>

<servlet-name>springmvc</servlet-name>

<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>

<!--contextConfigLocation配置springmvc加载的配置文件(配置处理器映射器、适配器等等)

若不配置，默认加载WEB-INF/servlet名称\-servlet(springmvc-servlet.xml)  -->

<init-param>

<param-name>contextConfigLocation</param-name>

<param-value>classpath:springmvc.xml</param-value>

</init-param>

</servlet>

<servlet-mapping>

<servlet-name>springmvc</servlet-name>

<url-pattern>\*.action</url-pattern>

</servlet-mapping>

<welcome-file-list>

<welcome-file>index.jsp</welcome-file>

</welcome-file-list>

</web-app>

**4. 配置文件springmvc.xml：（加载控制器ItemsController1）**

<beans xmlns=*"http://www.springframework.org/schema/beans"*

xmlns:xsi=*"http://www.w3.org/2001/XMLSchema-instance"* xmlns:mvc=*"http://www.springframework.org/schema/mvc"*

xmlns:context=*"http://www.springframework.org/schema/context"*

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-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/context*

* http://www.springframework.org/schema/context/spring-context-3.2.xsd*

*        http://www.springframework.org/schema/aop*

*        http://www.springframework.org/schema/aop/spring-aop-3.2.xsd*

*        http://www.springframework.org/schema/tx*

*        http://www.springframework.org/schema/tx/spring-tx-3.2.xsd "*>

****

<bean id=*"itemsController1"* name=*"/queryItems.action"* class=*"com.abc.ssm.controller.ItemsController1"*/>

****

<bean class=*"org.springframework.web.servlet.handler.BeanNameUrlHandlerMapping"*/>

****

<bean class=*"org.springframework.web.servlet.handler.SimpleUrlHandlerMapping"*>

<property name=*"mappings"*>

<props>

****

<prop key=*"queryItems1.action"*>itemsController1</prop>

<prop key=*"queryItems2.action"*>itemsController1</prop>

</props>

</property>

</bean>

** **

<bean class=*"org.springframework.web.servlet.mvc.SimpleControllerHandlerAdapter"*>

</bean>

** **

<bean class=*"org.springframework.web.servlet.view.InternalResourceViewResolver"*/>

</beans>

**5.实体类Items.Java:**

**package** com.abc.ssm.po;

**import** java.util.Date;

**public** **class** Items \{

**private** Integer id;

**private** String name;

**private** Float price;

**private** String pic;

**private** Date createtime;

**private** String detail;

**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 == **null** ? **null** : name.trim();

**public** Float getPrice() \{

**return** price;

**public** **void** setPrice(Float price) \{

**this**.price = price;

**public** String getPic() \{

**return** pic;

**public** **void** setPic(String pic) \{

**this**.pic = pic == **null** ? **null** : pic.trim();

**public** Date getCreatetime() \{

**return** createtime;

**public** **void** setCreatetime(Date createtime) \{

**this**.createtime = createtime;

**public** String getDetail() \{

**return** detail;

**public** **void** setDetail(String detail) \{

**this**.detail = detail == **null** ? **null** : detail.trim();

**6.开发非注解Handler(使用非注解的映射器和非注解的适配器)**

**控制器ItemsController1：**

package com.abc.ssm.controller;

import java.util.ArrayList;

import java.util.Date;

import java.util.List;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

import org.springframework.web.servlet.ModelAndView;

import org.springframework.web.servlet.mvc.Controller;

import com.abc.ssm.po.Items;

public class ItemsController1 implements Controller \{

public ModelAndView handleRequest(HttpServletRequest request,

HttpServletResponse response) throws Exception \{

//1调用Service查询数据库商品列表，此处用静态数据模拟

List<Items> itemsList= new ArrayList<Items>();

Items items\_1 = new  Items();

items\_1.setName("联想笔记本");

items\_1.setPrice(4000f);

items\_1.setCreatetime(new Date());

items\_1.setDetail("ThinkPad");

Items items\_2 = new  Items();

items\_2.setName("华为手机");

items\_2.setPrice(4000f);

items\_2.setCreatetime(new Date());

items\_2.setDetail("华为P10");

itemsList.add( items\_1);

itemsList.add( items\_2);

//2准备ModelAndView

ModelAndView modelAndView = new ModelAndView();

//在jsp中通过“itemsList”取数据

modelAndView.addObject("itemsList",itemsList);

//3指定视图

String viewName = "/WEB-INF/jsp/items/itemsList.jsp";

modelAndView.setViewName(viewName);

return modelAndView;

**7.JSP页面itemsList.jsp：**

<%@ page language=*"java"* contentType=*"text/html; charset=UTF-8"*

pageEncoding=*"UTF-8"*%>

<%@ taglib uri=*"http://java.sun.com/jsp/jstl/core"* prefix=*"c"* %>

<%@ taglib uri=*"http://java.sun.com/jsp/jstl/fmt"*  prefix=*"fmt"*%>

<%@page isELIgnored=*"false"*%>

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">

<html>

<head>

<title>查询商品列表</title>

</head>

<body>

<form action=*"*$\{pageContext.request.contextPath \}*/queryItems.action"* method=*"post"*>

查询条件：

<table width=*"100%"* border=*1*>

<tr>

</tr>

</table>

商品列表：

<table width=*"100%"* border=*1*>

<tr>

</tr>

<c:forEach items="$\{itemsList \}" var=*"item"*>

<tr>

<td>$\{item.price \}</td>

<td>$\{item.detail \}</td>

</tr>

</c:forEach>

</table>

</form>

</body>

</html>

**8.运行路径**：http://localhost:8080/SpringMVC\_01/queryItems.action

**9.运行结果：**

![70 2][]

[点击打开链接][Link 1]

** **

[70]: /images/20220523/94a0e0d71d21468d98613ed3521e9055.png
[70 1]: /images/20220523/8f65667a6b6f475596391634b2289407.png
[70 2]: /images/20220523/a41e776a2543415e8aa4f510564c1b5b.png
[Link 1]: https://download.csdn.net/download/qq_41224638/10448571