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标题: SpringMVC [打印本页]
作者: 何小豆儿在此    时间: 2023-7-12 16:37
标题: SpringMVC
SpringMVC

Spring集成web环境

集成步骤

ApplicationContext应用上下文的获取方式

之前每次我们都是通过new的方式创建的应用上下文，这样的弊端是在大项目中配置文件会加载多次，应用上下文被创建多次，繁琐且不节省资源
所以我们运用监听器来只创建一次，所有的用这一个容器，所以：

创建一个实现ServletContext监听器的类：
  1. public class ContextLoader implements ServletContextListener {
  2.     <mvc:annotation-driven conversion-service="ConversionService"/><context:component-scan base-package="com.myspring.controller"/>@Override
  3.     <mvc:annotation-driven conversion-service="ConversionService"/><context:component-scan base-package="com.myspring.controller"/>public void contextInitialized(ServletContextEvent sce) {
  4.     <mvc:annotation-driven conversion-service="ConversionService"/><context:component-scan base-package="com.myspring.controller"/>    <mvc:annotation-driven conversion-service="ConversionService"/><context:component-scan base-package="com.myspring.controller"/>ApplicationContext app = new ClassPathXmlApplicationContext("applicationContext.xml");
  5.     <mvc:annotation-driven conversion-service="ConversionService"/><context:component-scan base-package="com.myspring.controller"/>    <mvc:annotation-driven conversion-service="ConversionService"/><context:component-scan base-package="com.myspring.controller"/>//将这个应用上下文对象存储在servletContext域中
  6.     <mvc:annotation-driven conversion-service="ConversionService"/><context:component-scan base-package="com.myspring.controller"/>    <mvc:annotation-driven conversion-service="ConversionService"/><context:component-scan base-package="com.myspring.controller"/>ServletContext servletContext = sce.getServletContext();
  7.     <mvc:annotation-driven conversion-service="ConversionService"/><context:component-scan base-package="com.myspring.controller"/>    <mvc:annotation-driven conversion-service="ConversionService"/><context:component-scan base-package="com.myspring.controller"/>servletContext.setAttribute("app",app);
  8.     <mvc:annotation-driven conversion-service="ConversionService"/><context:component-scan base-package="com.myspring.controller"/>}
  10.     <mvc:annotation-driven conversion-service="ConversionService"/><context:component-scan base-package="com.myspring.controller"/>@Override
  11.     <mvc:annotation-driven conversion-service="ConversionService"/><context:component-scan base-package="com.myspring.controller"/>public void contextDestroyed(ServletContextEvent sce) {
  12.     <mvc:annotation-driven conversion-service="ConversionService"/><context:component-scan base-package="com.myspring.controller"/>}
  13. }
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web层中：
  1.     <mvc:annotation-driven conversion-service="ConversionService"/><context:component-scan base-package="com.myspring.controller"/>protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
  2.     <mvc:annotation-driven conversion-service="ConversionService"/><context:component-scan base-package="com.myspring.controller"/>    <mvc:annotation-driven conversion-service="ConversionService"/><context:component-scan base-package="com.myspring.controller"/>ServletContext servletContext = req.getServletContext();
  3.     <mvc:annotation-driven conversion-service="ConversionService"/><context:component-scan base-package="com.myspring.controller"/>    <mvc:annotation-driven conversion-service="ConversionService"/><context:component-scan base-package="com.myspring.controller"/>ApplicationContext app = (ApplicationContext) servletContext.getAttribute("app");
  4.     <mvc:annotation-driven conversion-service="ConversionService"/><context:component-scan base-package="com.myspring.controller"/>    <mvc:annotation-driven conversion-service="ConversionService"/><context:component-scan base-package="com.myspring.controller"/>UserService userService= app.getBean(UserService.class);
  5.     <mvc:annotation-driven conversion-service="ConversionService"/><context:component-scan base-package="com.myspring.controller"/>    <mvc:annotation-driven conversion-service="ConversionService"/><context:component-scan base-package="com.myspring.controller"/>userService.save();
  6.     <mvc:annotation-driven conversion-service="ConversionService"/><context:component-scan base-package="com.myspring.controller"/>}
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web.xml：
  1. <listener>
  2.   <listener-class>com.myspring.listener.ContextLoader</listener-class>
  3. </listener>
  5.   <context-param>
  6.     <mvc:annotation-driven conversion-service="ConversionService"/><context:component-scan base-package="com.myspring.controller"/><param-name>contextConfigLocation</param-name>
  7.     <mvc:annotation-driven conversion-service="ConversionService"/><context:component-scan base-package="com.myspring.controller"/><param-value>classpath:applicationContext.xml</param-value>
  8.   </context-param>
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Spring提供的获得应用上下文的工具

没错，上面又白写了。。。
上面的不用手动实现。Spring提供了一个监听器ContextLoaderListener就是对该功能的封装
我们只需要做两件事：
SpringMVC简介

SpringMVC开发步骤

流程：

SpringMVC的组件解析

SpringMVC内部执行流程



SpringMVC注解解析

@RequestMapping("")：地址映射
常用参数：value：就是路径
​                                method：可以指定请求方式。值为枚举方式在RequestMethod
​                                params：指定请求参数条件，例如：

​
  1. @Controller@RequestMapping("/user")public class UserController {    <mvc:annotation-driven conversion-service="ConversionService"/><context:component-scan base-package="com.myspring.controller"/>//当地址为localhost:8080/user/quick时访问该方法    <mvc:annotation-driven conversion-service="ConversionService"/><context:component-scan base-package="com.myspring.controller"/>@RequestMapping("/quick")    <mvc:annotation-driven conversion-service="ConversionService"/><context:component-scan base-package="com.myspring.controller"/>public  String save(){    <mvc:annotation-driven conversion-service="ConversionService"/><context:component-scan base-package="com.myspring.controller"/>    <mvc:annotation-driven conversion-service="ConversionService"/><context:component-scan base-package="com.myspring.controller"/>System.out.println("Controller save running");//    <mvc:annotation-driven conversion-service="ConversionService"/><context:component-scan base-package="com.myspring.controller"/>    <mvc:annotation-driven conversion-service="ConversionService"/><context:component-scan base-package="com.myspring.controller"/>要跳转的视图:localhost:8080/user/success.jsp,当前的前一级目录下的该资源（/success.jsp.就代表当前web应用下，即webapp目录下）    <mvc:annotation-driven conversion-service="ConversionService"/><context:component-scan base-package="com.myspring.controller"/>    <mvc:annotation-driven conversion-service="ConversionService"/><context:component-scan base-package="com.myspring.controller"/>return "success.jsp";    <mvc:annotation-driven conversion-service="ConversionService"/><context:component-scan base-package="com.myspring.controller"/>}}
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SpringMVC配置解析

在上面的代码中，最后我们renturn了jsp页面
  1. return "success.jsp";
  2. //实际上本句为
  3. return "forword:success.jsp";
  4. //forword在本处意思为转发（不改变url地址访问资源），默认为forword
  5. return "redirect:/success.jsp"
  6. //redirect:代表重定向
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我们还可以在springmvc中配置视图解析器，来避免写前缀后缀
  1.     <mvc:annotation-driven conversion-service="ConversionService"/><context:component-scan base-package="com.myspring.controller"/>    <mvc:annotation-driven conversion-service="ConversionService"/><context:component-scan base-package="com.myspring.controller"/>    <mvc:annotation-driven conversion-service="ConversionService"/><context:component-scan base-package="com.myspring.controller"/>    <mvc:annotation-driven conversion-service="ConversionService"/><context:component-scan base-package="com.myspring.controller"/>    <mvc:annotation-driven conversion-service="ConversionService"/><context:component-scan base-package="com.myspring.controller"/>    <mvc:annotation-driven conversion-service="ConversionService"/><context:component-scan base-package="com.myspring.controller"/>这样一来我们可以这样写：return "/success"代表：/jsp/success.jsp
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总结：

SpringMVC的数据响应

SpringMVC的数据响应方式：
页面跳转

​        返回字符串的形式也可以传递参数：
  1.     <mvc:annotation-driven conversion-service="ConversionService"/><context:component-scan base-package="com.myspring.controller"/>@RequestMapping("/quick")    <mvc:annotation-driven conversion-service="ConversionService"/><context:component-scan base-package="com.myspring.controller"/>public  String save(Model model){    <mvc:annotation-driven conversion-service="ConversionService"/><context:component-scan base-package="com.myspring.controller"/>    <mvc:annotation-driven conversion-service="ConversionService"/><context:component-scan base-package="com.myspring.controller"/>model.addAttribute("username","lihua");//    <mvc:annotation-driven conversion-service="ConversionService"/><context:component-scan base-package="com.myspring.controller"/>    <mvc:annotation-driven conversion-service="ConversionService"/><context:component-scan base-package="com.myspring.controller"/>要跳转的视图    <mvc:annotation-driven conversion-service="ConversionService"/><context:component-scan base-package="com.myspring.controller"/>    <mvc:annotation-driven conversion-service="ConversionService"/><context:component-scan base-package="com.myspring.controller"/>return "success";    <mvc:annotation-driven conversion-service="ConversionService"/><context:component-scan base-package="com.myspring.controller"/>}//另外代替Model，还可以传HttpServletRequest等作为参数
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​        在index.jsp中
  1. <%@ page contentType="text/html;charset=UTF-8" language="java" isELIgnored="false" %>
  2. 这个isELIgnored="false"表示el表达式可用
  3. <html>
  4. <body>
  5. <h2>Hello World!${username}</h2>
  6. </body>
  7. </html>
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回写数据

​        springmvc不需要我们自己来转json字符串，有更加简便的方式:
​        返回对象和集合。
​        首先需要我们在spring配置文件中进行一些配置（配置处理器映射器）：
  1.     <mvc:annotation-driven conversion-service="ConversionService"/><context:component-scan base-package="com.myspring.controller"/>    <mvc:annotation-driven conversion-service="ConversionService"/><context:component-scan base-package="com.myspring.controller"/>    <mvc:annotation-driven conversion-service="ConversionService"/><context:component-scan base-package="com.myspring.controller"/>    <mvc:annotation-driven conversion-service="ConversionService"/><context:component-scan base-package="com.myspring.controller"/>    <mvc:annotation-driven conversion-service="ConversionService"/><context:component-scan base-package="com.myspring.controller"/>    <mvc:annotation-driven conversion-service="ConversionService"/><context:component-scan base-package="com.myspring.controller"/>    <mvc:annotation-driven conversion-service="ConversionService"/><context:component-scan base-package="com.myspring.controller"/>    <mvc:annotation-driven conversion-service="ConversionService"/><context:component-scan base-package="com.myspring.controller"/>    <mvc:annotation-driven conversion-service="ConversionService"/><context:component-scan base-package="com.myspring.controller"/>    <mvc:annotation-driven conversion-service="ConversionService"/><context:component-scan base-package="com.myspring.controller"/>    <mvc:annotation-driven conversion-service="ConversionService"/><context:component-scan base-package="com.myspring.controller"/>    <mvc:annotation-driven conversion-service="ConversionService"/><context:component-scan base-package="com.myspring.controller"/>    <mvc:annotation-driven conversion-service="ConversionService"/><context:component-scan base-package="com.myspring.controller"/>    <mvc:annotation-driven conversion-service="ConversionService"/><context:component-scan base-package="com.myspring.controller"/>    <mvc:annotation-driven conversion-service="ConversionService"/><context:component-scan base-package="com.myspring.controller"/>    <mvc:annotation-driven conversion-service="ConversionService"/><context:component-scan base-package="com.myspring.controller"/>    <mvc:annotation-driven conversion-service="ConversionService"/><context:component-scan base-package="com.myspring.controller"/>    <mvc:annotation-driven conversion-service="ConversionService"/><context:component-scan base-package="com.myspring.controller"/>    <mvc:annotation-driven conversion-service="ConversionService"/><context:component-scan base-package="com.myspring.controller"/>    <mvc:annotation-driven conversion-service="ConversionService"/><context:component-scan base-package="com.myspring.controller"/>
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​        控制类中：
  1.     <mvc:annotation-driven conversion-service="ConversionService"/><context:component-scan base-package="com.myspring.controller"/>@RequestMapping("/quick")//    <mvc:annotation-driven conversion-service="ConversionService"/><context:component-scan base-package="com.myspring.controller"/>还是要写这个注解，因为还是返回的字符串数据    <mvc:annotation-driven conversion-service="ConversionService"/><context:component-scan base-package="com.myspring.controller"/>@ResponseBody    <mvc:annotation-driven conversion-service="ConversionService"/><context:component-scan base-package="com.myspring.controller"/>public UserServiceImpl save(HttpServletResponse response) throws IOException {    <mvc:annotation-driven conversion-service="ConversionService"/><context:component-scan base-package="com.myspring.controller"/>    <mvc:annotation-driven conversion-service="ConversionService"/><context:component-scan base-package="com.myspring.controller"/>UserServiceImpl userService = new UserServiceImpl();    <mvc:annotation-driven conversion-service="ConversionService"/><context:component-scan base-package="com.myspring.controller"/>    <mvc:annotation-driven conversion-service="ConversionService"/><context:component-scan base-package="com.myspring.controller"/>userService.setAge(10);    <mvc:annotation-driven conversion-service="ConversionService"/><context:component-scan base-package="com.myspring.controller"/>    <mvc:annotation-driven conversion-service="ConversionService"/><context:component-scan base-package="com.myspring.controller"/>userService.setName("lihua");    <mvc:annotation-driven conversion-service="ConversionService"/><context:component-scan base-package="com.myspring.controller"/>    <mvc:annotation-driven conversion-service="ConversionService"/><context:component-scan base-package="com.myspring.controller"/>return userService;    <mvc:annotation-driven conversion-service="ConversionService"/><context:component-scan base-package="com.myspring.controller"/>}
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配置太麻烦了，可以通过mvc的注解驱动代替上述配置，没错，又又又有更加简便的操作：

在springmvc的配置文件中：
  1.     <mvc:annotation-driven conversion-service="ConversionService"/><context:component-scan base-package="com.myspring.controller"/>    <mvc:annotation-driven conversion-service="ConversionService"/><context:component-scan base-package="com.myspring.controller"/>    <mvc:annotation-driven conversion-service="ConversionService"/><context:component-scan base-package="com.myspring.controller"/>    <mvc:annotation-driven conversion-service="ConversionService"/><context:component-scan base-package="com.myspring.controller"/>注意：注解驱动对应的命名空间必须是xmlns:mvc="http://www.springframework.org/schema/mvc"其他两个不行
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SpringMVC获取请求数据

获取请求参数




  1. @RequestMapping("/quick")@ResponseBodypublic void save(VO vo) throws IOException {    <mvc:annotation-driven conversion-service="ConversionService"/><context:component-scan base-package="com.myspring.controller"/>System.out.println(vo.getStringList());}
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当请求为Ajax可以通过指定contenttype为json格式，通过注解直接获取集合数据：
ajax：
  1. @RequestMapping("/quick")@ResponseBodypublic void save(@RequestBody List userList) throws IOException {    <mvc:annotation-driven conversion-service="ConversionService"/><context:component-scan base-package="com.myspring.controller"/>System.out.println(userList);}
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开放静态资源；
  1. 无法访问的js文件等静态资源是配置
  3.     <mvc:annotation-driven conversion-service="ConversionService"/><mvc:resources mapping="js/**" location="/js/"></mvc:resources><context:component-scan base-package="com.myspring.controller"/>
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这样也可以：在springmvc找不到资源是交给tomcat处理
  1. [/code][size=4]解决低版本tomcat请求数据为中文乱码问题[/size]
  3. 如果tomcat版本较低，当配置post请求时，数据为中文会出现乱码，所以我们通过配置过滤器来解决
  4. [code]  CharacterEncodingFilter  org.springframework.web.filter.CharacterEncodingFilter    <mvc:annotation-driven conversion-service="ConversionService"/><context:component-scan base-package="com.myspring.controller"/>  encoding    <mvc:annotation-driven conversion-service="ConversionService"/><context:component-scan base-package="com.myspring.controller"/>UTF-8    <mvc:annotation-driven conversion-service="ConversionService"/><context:component-scan base-package="com.myspring.controller"/>CharacterEncodingFilter  /*
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参数绑定注解@requestParam

当请求的参数名称和controller方法参数不一致时，就需要通过@requestParam注解显示
  1. @RequestMapping("/quick")@ResponseBody//当我在url中输入的是namepublic void save(@RequestParam("name") String username) throws IOException {    <mvc:annotation-driven conversion-service="ConversionService"/><context:component-scan base-package="com.myspring.controller"/>System.out.println(username);}
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@requestParam注解的参数：

获得Restful风格的参数

Restful是一种软件架构风格、设计风格，而不是标准，只是提供一组设计原则和约束条件。主要用于客户端和服务器交互类的软件，基于这个风格设计的软件可以更加简洁，更有层次等
HTTP协议中四个表示操作方式的动词：

具体实例：

自定义类型转换器

SpringMVC实际上已经具备了一些常用的类型转换器，例如客户端提交的字符串被转换成int型进行参数设置
但是可能并不完全满足我们的需求，所以我可以自定义类型转换器：
开发步骤：
获得Servlet的相关API

前面说过，直接在相关方法参数位置注入，就不在赘述

获取请求头

  1.     <mvc:annotation-driven conversion-service="ConversionService"/><context:component-scan base-package="com.myspring.controller"/>@RequestMapping("/quick")    <mvc:annotation-driven conversion-service="ConversionService"/><context:component-scan base-package="com.myspring.controller"/>@ResponseBody//    <mvc:annotation-driven conversion-service="ConversionService"/><context:component-scan base-package="com.myspring.controller"/>通过cookie的id获得cookie的值    <mvc:annotation-driven conversion-service="ConversionService"/><context:component-scan base-package="com.myspring.controller"/>public void save(@CookieValue(value = "JSESSIONID") String cookie) throws IOException {    <mvc:annotation-driven conversion-service="ConversionService"/><context:component-scan base-package="com.myspring.controller"/>    <mvc:annotation-driven conversion-service="ConversionService"/><context:component-scan base-package="com.myspring.controller"/>System.out.println(cookie);    <mvc:annotation-driven conversion-service="ConversionService"/><context:component-scan base-package="com.myspring.controller"/>}
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文件上传

文件上传客户端要求：

单文件上传步骤：
我在创建multipartResolver 实例时报500错误，后来发现是tomcat中没有commons-fileupload和commons-io的jar包，需要向tomcat下的lib目录手动导入上面那个两个坐标的包，另外可能jsp不识别el表达式需要在开头设置 isELIgnored="false"
多文件上传同理：
  1.     <mvc:annotation-driven conversion-service="ConversionService"/><context:component-scan base-package="com.myspring.controller"/>@RequestMapping("/quick")    <mvc:annotation-driven conversion-service="ConversionService"/><context:component-scan base-package="com.myspring.controller"/>@ResponseBody    <mvc:annotation-driven conversion-service="ConversionService"/><context:component-scan base-package="com.myspring.controller"/>//参数名必须与上传文件表单的各项name相同    <mvc:annotation-driven conversion-service="ConversionService"/><context:component-scan base-package="com.myspring.controller"/>public void save(String username, MultipartFile uploadFile1,MultipartFile uploadFile2) throws IOException {//    <mvc:annotation-driven conversion-service="ConversionService"/><context:component-scan base-package="com.myspring.controller"/>    <mvc:annotation-driven conversion-service="ConversionService"/><context:component-scan base-package="com.myspring.controller"/>获得文件名称    <mvc:annotation-driven conversion-service="ConversionService"/><context:component-scan base-package="com.myspring.controller"/>    <mvc:annotation-driven conversion-service="ConversionService"/><context:component-scan base-package="com.myspring.controller"/>String originalFilename = uploadFile1.getOriginalFilename();    <mvc:annotation-driven conversion-service="ConversionService"/><context:component-scan base-package="com.myspring.controller"/>    <mvc:annotation-driven conversion-service="ConversionService"/><context:component-scan base-package="com.myspring.controller"/>String originalFilename2 = uploadFile2.getOriginalFilename();//    <mvc:annotation-driven conversion-service="ConversionService"/><context:component-scan base-package="com.myspring.controller"/>    <mvc:annotation-driven conversion-service="ConversionService"/><context:component-scan base-package="com.myspring.controller"/>保存文件到    <mvc:annotation-driven conversion-service="ConversionService"/><context:component-scan base-package="com.myspring.controller"/>    <mvc:annotation-driven conversion-service="ConversionService"/><context:component-scan base-package="com.myspring.controller"/>uploadFile2.transferTo(new File("D:\"+originalFilename));    <mvc:annotation-driven conversion-service="ConversionService"/><context:component-scan base-package="com.myspring.controller"/>    <mvc:annotation-driven conversion-service="ConversionService"/><context:component-scan base-package="com.myspring.controller"/>uploadFile1.transferTo(new File("D:\"+originalFilename));    <mvc:annotation-driven conversion-service="ConversionService"/><context:component-scan base-package="com.myspring.controller"/>}
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当然也可以把参数换成一个数组

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