SpringMVC快速入门

创建maven web工程，引入依赖

<!-- 版本锁定 --> 
<properties> 
    <spring.version>5.0.2.RELEASE</spring.version>
</properties> 
<dependencies> 
    <dependency> 
        <groupId>org.springframework</groupId> 
        <artifactId>spring-context</artifactId> 
        <version>${spring.version}</version> 
    </dependency> 
    <dependency> 
        <groupId>org.springframework</groupId> 
        <artifactId>spring-web</artifactId> 
        <version>${spring.version}</version> 
    </dependency> 
    <dependency>
         <groupId>org.springframework</groupId> 
        <artifactId>spring-webmvc</artifactId> 
        <version>${spring.version}</version> 
    </dependency> 
    <dependency> 
        <groupId>javax.servlet</groupId>
         <artifactId>servlet-api</artifactId>
         <version>2.5</version> 
        <scope>provided</scope> 
    </dependency> 
    <dependency> 
        <groupId>javax.servlet.jsp</groupId> 
        <artifactId>jsp-api</artifactId> 
        <version>2.0</version> 
        <scope>provided</scope> 
     </dependency> 
</dependencies>

在wweb.xml中配置前端控制器（最重要）,配置中文乱码过滤器

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee
     http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd"
         version="4.0">

  <display-name>Archetype Created Web Application</display-name>

  <!--配置前端控制器-->
  <servlet>
    <servlet-name>dispatcherServlet</servlet-name>
    <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
     <!--配置springMVC的配置文件 -->
    <init-param>
      <param-name>contextConfigLocation</param-name>
      <param-value>classpath:springmvc.xml</param-value>
    </init-param>
    <!-- 让前端控制器是最先执行的servlet-->
    <load-on-startup>1</load-on-startup>
  </servlet>
  <servlet-mapping>
    <servlet-name>dispatcherServlet</servlet-name>
    <url-pattern>/</url-pattern>
  </servlet-mapping>

  <!--配置解决中文乱码的过滤器-->
  <filter>
    <filter-name>characterEncodingFilter</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>
  </filter>
  <filter-mapping>
    <filter-name>characterEncodingFilter</filter-name>
    <url-pattern>/*</url-pattern>
  </filter-mapping>
</web-app>

编写springMVC的配置文件

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:mvc="http://www.springframework.org/schema/mvc"
       xmlns:context="http://www.springframework.org/schema/context"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xsi:schemaLocation="
        http://www.springframework.org/schema/beans
        http://www.springframework.org/schema/beans/spring-beans.xsd
        http://www.springframework.org/schema/mvc
        http://www.springframework.org/schema/mvc/spring-mvc.xsd
        http://www.springframework.org/schema/context
        http://www.springframework.org/schema/context/spring-context.xsd">

    <!-- 开启注解扫描,Controller，异常处理，拦截器所在的包-->
    <context:component-scan base-package="cn.hao"/>

    <!-- 视图解析器对象 -->
    <bean id="internalResourceViewResolver" class="org.springframework.web.servlet.view.InternalResourceViewResolver">
        <property name="prefix" value="/WEB-INF/pages/"/>
        <property name="suffix" value=".jsp"/>
    </bean>
    <!--告诉前端控制器,哪些资源不拦截-->
    <mvc:resources mapping="/js/**" location="/js/"/>
    <mvc:resources mapping="/css/**" location="/css/"/>
    <mvc:resources mapping="/images/**" location="/images/"/>
    
    <!--配置异常处理器-->
    <bean class="cn.hao.exception.SysExceptionResolver" id="sysExceptionResolver"></bean>
    <!--配置多级拦截器-->
    <mvc:interceptors>
        <mvc:interceptor>
            <!--要拦截的具体的方法-->
            <mvc:mapping path="/user/*"/>
            <bean id="myInterceptor" class="cn.hao.Interceptor.MyInterceptor"></bean>
         </mvc:interceptor>
        <mvc:interceptor>
            <!--要拦截的具体的方法-->
            <mvc:mapping path="/user/*"/>
            <bean id="myInterceptor2" class="cn.hao.Interceptor.MyInterceptor2"></bean>
        </mvc:interceptor>

    </mvc:interceptors>
    <!-- 开启SpringMVC框架注解的支持 -->
    <mvc:annotation-driven />
</beans>

编写index.jsp和HelloController

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>Title</title>
</head>
<body>
    <h3>入门程序</h3>
    <a href="/user/testString">testString</a>
    <br>
    <a href="/user/testVoid">testVoid</a>
    <br>
    <a href="/user/testModelAndView">testModelAndView</a>
    <br>
    <a href="/user/testException">testException</a>
    <br>
    <h3>拦截器</h3>
    <a href="/user/testInterceptor">testInterceptor</a>
</body>
</html>

@Controller
@RequestMapping("/user")
public class UserController {

    @RequestMapping("/testString")
    public String testString(Model model) {
        System.out.println("testString方法执行了");

        //模拟从数据库查出来用户
        User user = new User();
        user.setUsername("小明");
        user.setPassword("1234");
        user.setAge(19);

        //存到model对象
        model.addAttribute("user", user);
        return "success";
    }

    @RequestMapping("/testVoid")
    public void testVoid(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        System.out.println("testVoid方法执行了");
//        request.getRequestDispatcher("/WEB-INF/pages/success.jsp").forward(request,response);
//        response.sendRedirect(request.getContextPath()+"/index2.jsp");
        response.setCharacterEncoding("UTF-8");
        response.setContentType("text/html;charset=utf-8");
        response.getWriter().println("<h1 >你好<h1>");
        return;
    }

    @RequestMapping("/testModelAndView")
    public ModelAndView testModelAndView() {
        System.out.println("testModelAndView方法执行了");

        ModelAndView mv = new ModelAndView();

        User user = new User();
        user.setUsername("小丑");
        user.setPassword("1234");
        user.setAge(19);

        mv.addObject("user", user);
        mv.setViewName("success");
        return mv;
    }

    @RequestMapping("/testAjax")
    public @ResponseBody User testAjax(@RequestBody User user) {
        System.out.println("testAjax方法执行了");
        System.out.println(user);

        //响应，模拟查询数据库
        user.setUsername("Rose");
        user.setAge(33);
        return user;

    }

    @RequestMapping("/fileUpload1")
    public String fileUpload1(HttpServletRequest request) throws Exception {
        System.out.println("fileUpload1方法执行了");
        String path = request.getSession().getServletContext().getRealPath("/uploads/");
        File file = new File(path);
        if (!file.exists()) {
            file.mkdirs();
        }
        DiskFileItemFactory factory = new DiskFileItemFactory();
        ServletFileUpload upload = new ServletFileUpload(factory);

        List<FileItem> fileItems = upload.parseRequest(request);

        for (FileItem item : fileItems) {
            if (item.isFormField()) {
                //普通
            } else {
                //文件
                String name = item.getName();
                String s = UUID.randomUUID().toString().replace("-", "");
                name = s + name;
                item.write(new File(path, name));
                item.delete();
            }
        }

        return "success";
    }

    @RequestMapping("/fileUpload2")
    public String fileUpload2(HttpServletRequest request, MultipartFile upload) throws Exception {
        System.out.println("fileUpload2方法执行了");

        String path = request.getSession().getServletContext().getRealPath("/uploads/");
        File file = new File(path);
        if (!file.exists()) {
            file.mkdirs();
        }

        String name = upload.getOriginalFilename();
        String s = UUID.randomUUID().toString().replace("-", "");
        name = s + name;
        upload.transferTo(new File(path, name));
        return "success";
    }

    @RequestMapping("/fileUpload3")
    public String fileUpload3(MultipartFile upload) throws Exception {
        System.out.println("fileUpload3方法执行了");
        //定义上传服务器的路径
        String path = "http://localhost:8081/uploads/";

        String name = upload.getOriginalFilename();
        String s = UUID.randomUUID().toString().replace("-", "");
        name = s + name;
        //跨服务器上传
        //创建客户端对象
        Client client = Client.create();
        //和服务器连接
        WebResource resource = client.resource(path + name);
        //上传
        resource.put(upload.getBytes());
        return "success";
    }

    @RequestMapping("/testException")
    public String testException() throws SysException {
        System.out.println("testException方法执行了");
        try {
            int a = 10 / 0;
        } catch (Exception e) {
            e.printStackTrace();
            throw new SysException("查询所有用户出现错误");
        }
        return "success";
    }

    @RequestMapping("/testInterceptor")
    public String testInterceptor() {
        System.out.println("testInterceptor方法执行了");

        return "success";
    }

}

在WEB-INF目录下创建pages文件夹，编写success.jsp的成功页面

<%@ page contentType="text/html;charset=UTF-8" language="java" isELIgnored="false" %>
<html>
<head>
    <title>Title</title>
</head>
<body>

    <h3>执行成功</h3>

    ${user.username}
    ${user.password}
    ${user.age}
    <% System.out.println("success.jsp执行了"); %>
</body>
</html>

启动Tomcat服务器，进行测试

项目结构