---

拦截器

Spring MVC可以使用拦截器对请求进行拦截处理，用户可以自定义拦截器来实现特定的功能，自定义的拦截器必须实现HandlerInterceptor接口，重写以下3个方法。

    @Override

    public boolean preHandle(HttpServletRequest request, HttpServletResponse response,

            Object handler) throws Exception {

        // TODO Auto-generated method stub

        String a = request.getParameter("a");

        if(a.equals("10")){

            //通过

            return true;

        }else{

            //不通过

            response.sendRedirect("../inter2.jsp");

        }

        return false;

    }

    /**

     * 在渲染View之后被调用，可以用来释放资源

     */

    @Override

    public void afterCompletion(HttpServletRequest arg0,

            HttpServletResponse arg1, Object arg2, Exception arg3)

            throws Exception {

        // TODO Auto-generated method stub

    }

    /**

     * 在调用目标方法之后，在渲染界面之前被启用

     * 可以对模型及数据进行调整

     */

    @Override

    public void postHandle(HttpServletRequest arg0, HttpServletResponse arg1,

            Object arg2, ModelAndView arg3) throws Exception {

        // TODO Auto-generated method stub

    }

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文件上传

导包

commons-fileupload-1.2.jar

import java.io.File;

import java.io.IOException;

import javax.servlet.http.HttpSession;

import org.springframework.stereotype.Controller;

import org.springframework.web.bind.annotation.RequestMapping;

import org.springframework.web.multipart.MultipartFile;

@Controller

@RequestMapping("/upload")

public class UploadController {

    @RequestMapping("/l1")

    public String upload(MultipartFile file,HttpSession session) throws IllegalStateException, IOException{

        //验证文件是否为空

        if(!file.isEmpty()) {

            //文件命名:当前时间毫秒数+原图的名字

            String fileName=System.currentTimeMillis()+file.getOriginalFilename();

            //服务器的上传路径

            String location=session.getServletContext().getRealPath("upload");

            //上传文件

            file.transferTo(new File(location+"/"+fileName));

        }

        return "success";

    }

}

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-中文乱码解决

在web.xml中进行配置。

  <filter>

   <filter-name>EncodingFilter</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>EncodingFilter</filter-name>

   <url-pattern>/*</url-pattern>

  </filter-mapping>

---

rest风格：

一种互联网软件架构。

HTTP协议的四种基本操作：

• GET获取资源
• POST新建资源
• PUT更新资源
• DELETE删除资源

rest风格的URL配置：

import java.io.PrintWriter;

import javax.servlet.http.HttpServletRequest;

import org.springframework.http.HttpMethod;

import org.springframework.stereotype.Controller;

import org.springframework.web.bind.annotation.RequestMapping;

@Controller

@RequestMapping("/rest")

public class RestController {

    @RequestMapping("/r1")

    public void r1(HttpServletRequest request,PrintWriter pw){

        System.out.println(request.getMethod());

        switch (request.getMethod()) {

        //获取数据

        case "GET":

            //...

            System.out.println("获取数据");

            break;

        //添加数据

        case "POST":

            //...

            System.out.println("添加数据");

            break;

        //更新数据

        case "PUT":

            //...

            System.out.println("更新数据");

            break;

        //删除数据

        case "DELETE":

            //...

            System.out.println("删除数据");

            break;

        }

    }

}

在web.xml中进行rest风格组件相关配置

 <!-- rest风格支持组件(支持表单向提交PUT/DELETE方法) -->

  <filter>

    <filter-name>hidden</filter-name>

    <filter-class>org.springframework.web.filter.HiddenHttpMethodFilter</filter-class>

  </filter>

  <filter-mapping>

    <filter-name>hidden</filter-name>

    <url-pattern>/*</url-pattern>

  </filter-mapping>

---

异常处理机制

异常处理机制：将遇到的错误进行封装。

在servlet.xml中配置错误处理解析器。

    <!-- 错误处理解析器 -->

    <!-- <bean

        id="exceptionResolver"

        class="com.jredu.exception.MyExceptionHandler"/> -->

import org.springframework.stereotype.Controller;

import org.springframework.web.bind.annotation.RequestMapping;

import com.jredu.entity.User;

@Controller

@RequestMapping("/error")

public class ErrorController {

    @RequestMapping("/e1")

    public String e1(){

        User user=null;

        System.out.println(user.getPwd());

        return "hello";

    }

}

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

import org.springframework.web.servlet.HandlerExceptionResolver;

import org.springframework.web.servlet.ModelAndView;

/**

 * 异常处理捕获监听器

 * @author Administrator

 *

 */

public class MyExceptionHandler implements HandlerExceptionResolver{

    @Override

    public ModelAndView resolveException(HttpServletRequest request,

            HttpServletResponse response, Object handler, Exception ex) {

        // TODO Auto-generated method stub

        ModelAndView mav=new ModelAndView("exception");

        return mav;

    }

}