ServletRequest

简述

其实就是对于请求报文的封装，一般就是HttpServletRequest。

常用方法

  1. package com.simon.request;
  3. import javax.servlet.ServletException;
  4. import javax.servlet.annotation.WebServlet;
  5. import javax.servlet.http.HttpServlet;
  6. import javax.servlet.http.HttpServletRequest;
  7. import javax.servlet.http.HttpServletResponse;
  8. import java.io.IOException;
  9. import java.util.Enumeration;
  11. @WebServlet("/request1")
  12. public class RequestServlet1 extends HttpServlet {
  13.     protected void doPost(HttpServletRequest request, HttpServletResponse response)
  14.         throws ServletException, IOException {
  16.     }
  18.     protected void doGet(HttpServletRequest request, HttpServletResponse response)
  19.         throws ServletException, IOException {
  20.         //
  21.         String method = request.getMethod();
  22.         //  /app/request1
  23.         String requestURI = request.getRequestURI();
  24.         //  http://localhost/app/request1   requestURL = 协议 + 主机端口号 + requestURI
  25.         String requestURL = request.getRequestURL().toString();
  26.         String protocol = request.getProtocol();
  27.         System.out.println(method + " " + requestURI + " " + protocol);
  28.         System.out.println(method + " " + requestURL + " " + protocol);
  29.         Enumeration<String> headerNames = request.getHeaderNames();
  30.         while (headerNames.hasMoreElements()){
  31.             String key = headerNames.nextElement();
  32.             String value = request.getHeader(key);
  33.             System.out.println(key + ":" + value);
  34.         }
  35.         //请求体
  36.         //request.getInputStream();
  37.     }
  38. }

除此之外还可以获取到客户端和服务器主机的一些信息:

  1. package com.simon.request;
  3. import javax.servlet.ServletException;
  4. import javax.servlet.annotation.WebServlet;
  5. import javax.servlet.http.HttpServlet;
  6. import javax.servlet.http.HttpServletRequest;
  7. import javax.servlet.http.HttpServletResponse;
  8. import java.io.IOException;
  9. import java.util.Enumeration;
  11. @WebServlet("/request2")
  12. public class RequestServlet2 extends HttpServlet {
  13.     protected void doPost(HttpServletRequest request, HttpServletResponse response) 
  14.         throws ServletException, IOException {
  16.     }
  18.     protected void doGet(HttpServletRequest request, HttpServletResponse response)
  19.         throws ServletException, IOException {
  20.        //request还可以获取客户机和服务器主机的一些信息
  21.         String localAddr = request.getLocalAddr();
  22.         int localPort = request.getLocalPort();
  24.         String remoteAddr = request.getRemoteAddr();
  25.         int remotePort = request.getRemotePort();
  26.         System.out.println("客户机:" + remoteAddr + "使用端口号:" + remotePort + 
  27.                            "访问了服务器主机:" + localAddr + " 服务器端口号:" + localPort);
  28.     }
  29. }

Web服务器收到客户端的http请求，会针对每一次请求，分别创建一个用于代表请求的request对象、和代表响应的response对象。
那么，频繁地去刷新同一个链接,会创建多个request对象还是一个request对象呢?多个request对象.

使用场景

最常用的使用场景就是获取请求参数，比如登录一个网站,需要用户输入用户名密码。点击登录,会发送一个HTTP请求,HTTP请求报文、用户名、密码会随着HTTP请求报文携带到服务器上面去；
用户名、密码在请求报文中，接下来，我们需要做的就是从请求报文中取出用户名、密码，做校验。

  1. <!DOCTYPE html>
  2. <html lang="en">
  3. <head>
  4.     <meta charset="UTF-8">
  5.     <title>Title</title>
  6. </head>
  7. <body>
  8. <form action="/servlet/login" method="post">
  9.     用户名：<input type="text" name="username"/><br>
  10.     密码：<input type="password" name="password"/><br>
  11.     <input type="checkbox" name="hobby" value="Java">Java<br>
  12.     <input type="checkbox" name="hobby" value="PHP">PHP<br>
  13.     <input type="submit"/>
  14. </form>
  15. </body>
  16. </html>
  1. <!DOCTYPE html>
  2. <html lang="en">
  3. <head>
  4.     <meta charset="UTF-8">
  5.     <title>Title</title>
  6. </head>
  7. <body>
  8. what happen
  9. </body>
  10. </html>
  1. package com.simon.request;
  3. import javax.servlet.RequestDispatcher;
  4. import javax.servlet.ServletException;
  5. import javax.servlet.annotation.WebServlet;
  6. import javax.servlet.http.HttpServlet;
  7. import javax.servlet.http.HttpServletRequest;
  8. import javax.servlet.http.HttpServletResponse;
  9. import java.io.IOException;
  10. import java.util.Arrays;
  11. import java.util.Enumeration;
  13. @WebServlet("/login")
  14. public class LoginServlet extends HttpServlet {
  15.     @Override
  16.     protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
  17.         req.setCharacterEncoding("utf-8");
  18.       //getParameter()方法不仅可以获取请求体里面的请求参数，还可以获取在请求行的请求参数
  19.       //但是该方法也有限定条件，它只能获取key=value&key=value型的数据
  20.       String username = req.getParameter("username");
  21.         String password = req.getParameter("password");
  22.         if ("zs".equals(username)&&"abc".equals(password)){
  24.             Enumeration<String> parameterNames = req.getParameterNames();
  25.             while (parameterNames.hasMoreElements()){
  26.                 String parameterName = parameterNames.nextElement();
  27.                 String[] parameterValues = req.getParameterValues(parameterName);
  28.                 if (1 == parameterValues.length ){
  30.                     System.out.println(parameterName + ":" + parameterValues[0]);
  31.                 }else {
  32.                     System.out.println(parameterName + ":" + Arrays.toString(parameterValues));
  33.                 }
  34.             }
  36.             resp.setContentType("text/html;charset=utf-8");
  37.             resp.getWriter().println("恭喜，登陆成功即将跳转....");
  38.             RequestDispatcher dispatcher = req.getRequestDispatcher("/success.html");
  39.             dispatcher.forward(req,resp);
  40.         }
  42.     }
  43. }

image.png

Request域

共享空间。Request对象中存在一个map，如果能够拿到同一个request对象，那么就能够共享这个map
但是，哪些组件可以拿到同一个request对象
刷新同一个页面的多个请求可以共享request域吗？
不可以
转发的两个组件之间 共享request域。
如果某个servlet需要将数据和另外一个servlet进行共享，不仅仅可以通过context域进行共享，还可以利用request域来共享
比如某个servlet运行时获取到了商品的数据，接下来需要在另外一个servlet中去做一些格式化，Wed 2020-
context域：范围很大。所有的servlet均可以共享
request域：很小，只有这两个组件之间可以共享。假设你的场景需求就是在这个请求内需要共享，出了这个请求，就不需要共享，那么完全可以使用request域，而不需要使用context域，有点浪费

ServletResponse

常规API

  1. package com.simon.response;
  3. import javax.servlet.ServletException;
  4. import javax.servlet.annotation.WebServlet;
  5. import javax.servlet.http.HttpServlet;
  6. import javax.servlet.http.HttpServletRequest;
  7. import javax.servlet.http.HttpServletResponse;
  8. import java.io.IOException;
  10. @WebServlet("/response1")
  11. public class ServletResponseDemo1 extends HttpServlet {
  12.     @Override
  13.     protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
  14.         resp.setStatus(404);
  15.         resp.setHeader("Content-Type","text/html");
  16.         resp.getWriter().println("<h1 style='color:red'>File Not Found</h1>");
  18.         //服务器接收参数和发送参数，都可设置编码格式；
  19.         //接收时，我设置请求报文的编码格式供我解析
  20.         //发送时，指定utf-8，但要告知给客户端，放在响应头/体，让客户端也以这个格式解析我
  21.         resp.setContentType("text/html;charset=utf-8");
  22.         resp.getWriter().println("你好");
  23.     }
  24. }

缺省Servlet

要求：在当前应用中实现缺省Servlet的功能，url-pattern必须是/，把这些文件正常显示出来；如果文件不存在，显示404。

  1. package com.simon.response;
  3. import javax.servlet.ServletException;
  4. import javax.servlet.ServletOutputStream;
  5. import javax.servlet.annotation.WebServlet;
  6. import javax.servlet.http.HttpServlet;
  7. import javax.servlet.http.HttpServletRequest;
  8. import javax.servlet.http.HttpServletResponse;
  9. import java.io.File;
  10. import java.io.FileInputStream;
  11. import java.io.IOException;
  13. @WebServlet("/")
  14. public class ServletResponseDemo2 extends HttpServlet {
  15.     @Override
  16.     protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
  17.         //显示处缺省servlet的某一个文件，比如2.html
  18.         //ServletOutputStream：只需要将文件写入到response的缓冲区即可，tomcat会读取这个response里面
  19.         //的内容，然后生成响应报文
  20.         ServletOutputStream outputStream = resp.getOutputStream();
  21.         String realPath = getServletContext().getRealPath("WEB-INF/2.html");
  22.         FileInputStream inputStream = new FileInputStream(new File(realPath));
  23.         int length = 0;
  24.         byte[] bytes = new byte[1024];
  25.         while ((length = inputStream.read(bytes)) != -1){
  26.             outputStream.write(bytes,0,length);
  27.         }
  28.         inputStream.close();
  29.         ////输出流可以关闭也可以不关闭，如果不关闭，tomcat会帮你关闭
  30.         outputStream.close();
  31.     }
  32. }

image.png

重定向、刷新和转发

  1. package com.simon.response;
  3. import javax.servlet.ServletException;
  4. import javax.servlet.annotation.WebServlet;
  5. import javax.servlet.http.HttpServlet;
  6. import javax.servlet.http.HttpServletRequest;
  7. import javax.servlet.http.HttpServletResponse;
  8. import java.io.IOException;
  10. @WebServlet("/redirect")
  11. public class ServletResponseDemo4 extends HttpServlet {
  12.     @Override
  13.     protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
  15.         resp.sendRedirect("url="+req.getContextPath()+"/1.html");
  16.     }
  17. }
  1. package com.simon.response;
  3. import javax.servlet.ServletException;
  4. import javax.servlet.annotation.WebServlet;
  5. import javax.servlet.http.HttpServlet;
  6. import javax.servlet.http.HttpServletRequest;
  7. import javax.servlet.http.HttpServletResponse;
  8. import java.io.IOException;
  9. import java.text.SimpleDateFormat;
  10. import java.util.Date;
  12. @WebServlet("/refresh")
  13. public class ServletResponseDemo3 extends HttpServlet {
  14.     @Override
  15.     protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
  16.         //refresh有2个作用：①定时刷新    ②页面跳转
  18.         SimpleDateFormat simpleDateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
  19.         String dateFormat = simpleDateFormat.format(new Date());
  20.         //每2秒刷新一次
  21.         resp.getWriter().println(dateFormat);
  22.         resp.setHeader("refresh","2");
  24. //        resp.setHeader("refresh","3;url=https://www.baidu.com");
  25.         resp.setHeader("refresh","3;url="+req.getContextPath()+"/login.html");
  26.     }
  27. }
  1. package com.simon.request;
  3. import javax.servlet.RequestDispatcher;
  4. import javax.servlet.ServletException;
  5. import javax.servlet.annotation.WebServlet;
  6. import javax.servlet.http.HttpServlet;
  7. import javax.servlet.http.HttpServletRequest;
  8. import javax.servlet.http.HttpServletResponse;
  9. import java.io.IOException;
  10. import java.util.Arrays;
  11. import java.util.Enumeration;
  13. @WebServlet("/login")
  14. public class LoginServlet extends HttpServlet {
  15.     @Override
  16.     protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
  17.         req.setCharacterEncoding("utf-8");
  18.         String username = req.getParameter("username");
  19.         String password = req.getParameter("password");
  20.         if ("zs".equals(username)&&"abc".equals(password)){
  22.             Enumeration<String> parameterNames = req.getParameterNames();
  23.             while (parameterNames.hasMoreElements()){
  24.                 String parameterName = parameterNames.nextElement();
  25.                 String[] parameterValues = req.getParameterValues(parameterName);
  26.                 if (1 == parameterValues.length ){
  28.                     System.out.println(parameterName + ":" + parameterValues[0]);
  29.                 }else {
  30.                     System.out.println(parameterName + ":" + Arrays.toString(parameterValues));
  31.                 }
  32.             }
  34.             resp.setContentType("text/html;charset=utf-8");
  35.             resp.getWriter().println("恭喜，登陆成功即将跳转....");
  36.             RequestDispatcher dispatcher = req.getRequestDispatcher("/success.html");
  37.             dispatcher.forward(req,resp);
  38.         }
  39.     }
  40. }

三个页面跳转之间的区别

联系：都可以进行页面的跳转
区别：
1.状态码不同。重定向是302，转发、刷新都是200
2.能否共享request域。转发可以共享request域，其他两种是不可以的
3.响应头不一致。转发没有响应头；刷新是refresh响应头；重定向是Location响应头
4.请求次数不同。转发只发了一次请求，刷新、重定向都是多次
5.介导对象不同。转发是request介导的；刷新、重定向是response介导的
6.请求方法不同。转发前后请求方法不变（转发前是post请求，转发后还是post请求），但是对于刷新、重定向，后面会变成get请求。
7.跳转的范围不同。转发只可以在当前应用下调转，刷新、重定向是没有限制的

文件下载

  1. package com.simon.download;
  3. import javax.servlet.ServletException;
  4. import javax.servlet.ServletOutputStream;
  5. import javax.servlet.annotation.WebServlet;
  6. import javax.servlet.http.HttpServlet;
  7. import javax.servlet.http.HttpServletRequest;
  8. import javax.servlet.http.HttpServletResponse;
  9. import java.io.FileInputStream;
  10. import java.io.IOException;
  12. @WebServlet("/download")
  13. public class DownloadServlet extends HttpServlet {
  14.     @Override
  15.     protected void doGet(HttpServletRequest req, HttpServletResponse resp) 
  16.         throws ServletException, IOException {
  17.         //将WEB-INF目录下的1.txt文件下载到本地硬盘上面，而不是直接打开该文件
  18.         String realPath = getServletContext().getRealPath("WEB-INF/1.txt");
  19.         FileInputStream inputStream = new FileInputStream(realPath);
  20.         //key code line
  21.         resp.setHeader("Content-Disposition","attachment;filename=1.txt");
  22.         ServletOutputStream outputStream = resp.getOutputStream();
  23.         int length = 0;
  24.         byte[] bytes = new byte[1024];
  25.         while ((length=inputStream.read(bytes)) != -1){
  26.             outputStream.write(bytes,0,length);
  27.         }
  28.     }
  29. }

image.png
使用场景：做后台管理系统，会有导出的功能。

三种查看图片文件的方式

image.png

  1. <!DOCTYPE html>
  2. <html lang="en">
  3. <head>
  4.     <meta charset="UTF-8">
  5.     <title>Title</title>
  6. </head>
  7. <body>
  8. <a href="/app/threeGirls.jpg">点我直接查看图片</a>
  9. <a href="/app/pic/view">点我通过servlet查看图片</a>
  10. <a href="/app/pic/download">点我下载图片</a>
  12. <a href="/app/pic2?op=view2">点我通过servlet查看图片,改进版</a>
  13. <a href="/app/pic2?op=download2">点我下载图片，改进版</a>
  15. </body>
  16. </html>

初级版

  1. package com.simon.download;
  3. import javax.servlet.ServletException;
  4. import javax.servlet.ServletOutputStream;
  5. import javax.servlet.annotation.WebServlet;
  6. import javax.servlet.http.HttpServlet;
  7. import javax.servlet.http.HttpServletRequest;
  8. import javax.servlet.http.HttpServletResponse;
  9. import java.io.FileInputStream;
  10. import java.io.FileNotFoundException;
  11. import java.io.IOException;
  13. @WebServlet("/pic/*")
  14. public class ShowServlet extends HttpServlet {
  15.     @Override
  16.     protected void doGet(HttpServletRequest req, HttpServletResponse resp) 
  17.       throws ServletException, IOException {
  18.         String requestURI = req.getRequestURI();
  19.         String action = requestURI.replace(req.getContextPath() + "/pic/", "");
  20.         if ("view".equals(action)){
  21.             show(req,resp);
  22.         }
  23.         if ("download".equals(action)){
  24.             resp.setHeader("Content-Disposition","attachment;filename=threeGirls.jpg");
  25.             show(req,resp);
  26.         }
  27.     }
  29.     private void show(HttpServletRequest req, HttpServletResponse resp) 
  30.       throws IOException {
  31.         String realPath = getServletContext().getRealPath("/threeGirls.jpg");
  32.         FileInputStream inputStream = new FileInputStream(realPath);
  33.         ServletOutputStream outputStream = resp.getOutputStream();
  34.         int length = 0;
  35.         byte[] bytes = new byte[1024];
  36.         while ((length = inputStream.read(bytes)) != -1) {
  37.             outputStream.write(bytes, 0, length);
  38.         }
  40.     }
  41. }

改进版

  1. package com.simon.download;
  3. import javax.servlet.ServletException;
  4. import javax.servlet.ServletOutputStream;
  5. import javax.servlet.annotation.WebServlet;
  6. import javax.servlet.http.HttpServlet;
  7. import javax.servlet.http.HttpServletRequest;
  8. import javax.servlet.http.HttpServletResponse;
  9. import java.io.FileInputStream;
  10. import java.io.IOException;
  12. @WebServlet("/pic2")
  13. public class ShowServlet2 extends HttpServlet {
  14.     @Override
  15.     protected void doGet(HttpServletRequest req, HttpServletResponse resp) 
  16.         throws ServletException, IOException {
  17. //        String requestURI = req.getRequestURI();
  18. //        String action = requestURI.replace(req.getContextPath() + "/pic/", "");
  19.         String action = req.getParameter("op");
  20.         if ("view2".equals(action)){
  21.             show(req,resp);
  22.         }
  23.         if ("download2".equals(action)){
  24.             resp.setHeader("Content-Disposition","attachment;filename=threeGirls.jpg");
  25.             show(req,resp);
  26.         }
  27.     }
  29.     private void show(HttpServletRequest req, HttpServletResponse resp) 
  30.         throws IOException {
  31.         String realPath = getServletContext().getRealPath("/threeGirls.jpg");
  32.         FileInputStream inputStream = new FileInputStream(realPath);
  33.         ServletOutputStream outputStream = resp.getOutputStream();
  34.         int length = 0;
  35.         byte[] bytes = new byte[1024];
  36.         while ((length = inputStream.read(bytes)) != -1) {
  37.             outputStream.write(bytes, 0, length);
  38.         }
  40.     }
  41. }

文件上传

需求：将一个图片文件上传到web目录下的image目录的threeGirls.jpg文件去。

失败版

  1. <!DOCTYPE html>
  2. <html lang="en">
  3. <head>
  4.     <meta charset="UTF-8">
  5.     <title>Title</title>
  6. </head>
  7. <body>
  8. <form action="/app/upload1" enctype="multipart/form-data" method="post">
  9.     <input type="file" name="image"><br>
  10.     <input type="submit">
  11. </form>
  12. </body>
  13. </html>
  1. package com.simon.upload;
  3. import javax.servlet.ServletException;
  4. import javax.servlet.ServletInputStream;
  5. import javax.servlet.annotation.WebServlet;
  6. import javax.servlet.http.HttpServlet;
  7. import javax.servlet.http.HttpServletRequest;
  8. import javax.servlet.http.HttpServletResponse;
  9. import java.io.File;
  10. import java.io.FileOutputStream;
  11. import java.io.IOException;
  13. @WebServlet("/upload1")
  14. public class UploadServlet1 extends HttpServlet {
  15.     @Override
  16.     protected void doPost(HttpServletRequest req, HttpServletResponse resp) 
  17.       throws ServletException, IOException {
  18.         //先拿到请求报文的输入流
  19.         ServletInputStream inputStream = req.getInputStream();
  21.         //放到服务器的某个地方，比如部署根目录的image/threeGirls.jpg
  22.         String realPath = getServletContext().getRealPath("/image/threeGirls.jpg");
  23.         File file = new File(realPath);
  24.         if (!file.getParentFile().exists()){
  25.             file.getParentFile().mkdirs();
  26.         }
  27.         FileOutputStream outputStream = new FileOutputStream(file);
  28.         byte[] bytes = new byte[1024];
  29.         int length = 0;
  30.         while ((length=inputStream.read(bytes)) != -1){
  31.             outputStream.write(bytes,0,length);
  32.         }
  33.         outputStream.close();
  35.     }
  36. }

image.png

解决办法

  1. <!DOCTYPE html>
  2. <html lang="en">
  3. <head>
  4.     <meta charset="UTF-8">
  5.     <title>Title</title>
  6. </head>
  7. <body>
  8. <form action="/app/upload2" enctype="multipart/form-data" method="post">
  9.     <input type="file" name="image"><br>
  10.     <input type="text" name="username"><br>
  11.     <input type="password" name="password"><br>
  12.     <input type="submit">
  13. </form>
  14. </body>
  15. </html>
  1. package com.simon.upload;
  3. import org.apache.commons.fileupload.FileItem;
  4. import org.apache.commons.fileupload.FileUploadException;
  5. import org.apache.commons.fileupload.disk.DiskFileItemFactory;
  6. import org.apache.commons.fileupload.servlet.ServletFileUpload;
  8. import javax.servlet.ServletContext;
  9. import javax.servlet.ServletException;
  10. import javax.servlet.ServletInputStream;
  11. import javax.servlet.annotation.WebServlet;
  12. import javax.servlet.http.HttpServlet;
  13. import javax.servlet.http.HttpServletRequest;
  14. import javax.servlet.http.HttpServletResponse;
  15. import java.io.File;
  16. import java.io.FileOutputStream;
  17. import java.io.IOException;
  18. import java.util.Iterator;
  19. import java.util.List;
  21. //提交含文件的表单，上传到服务器
  22. @WebServlet("/upload2")
  23. public class UploadServlet2 extends HttpServlet {
  24.     @Override
  25.     protected void doPost(HttpServletRequest req, HttpServletResponse resp) 
  26.       throws ServletException, IOException {
  28.         List<FileItem> fileItems = null;
  29.         DiskFileItemFactory itemFactory = null;
  30.         FileItem item = null;
  32.         //确保request对象包含上传的文件
  33.         boolean isMultipart = ServletFileUpload.isMultipartContent(req);
  34.         if (!isMultipart)   return;
  36.         //创建对应form表单key-value工厂，用以缓存临时文件
  37.         DiskFileItemFactory factory = new DiskFileItemFactory();
  38.         ServletContext servletContext = getServletContext();
  39.         File repository = (File) servletContext
  40.           .getAttribute("javax.servlet.context.tempdir");
  41.         factory.setRepository(repository);
  43.         //将缓存区的文件提交给request以供后续对象来解析
  44.         ServletFileUpload upload = new ServletFileUpload(factory);
  45.         try {
  46.             fileItems = upload.parseRequest(req);
  47.             Iterator<FileItem> iterator = fileItems.iterator();
  48.             while (iterator.hasNext()){
  49.                 item = iterator.next();
  50.                 if (item.isFormField()){
  51.                     processUploadedFile(item);
  52.                 }else {
  53.                     processFormField(item);
  54.                 }
  55.             }
  56.         } catch (FileUploadException e) {
  57.             e.printStackTrace();
  58.         }
  60.         //根据form表单里key值是否为文件类型，分类解析
  61.         //最终将文件写入到硬盘的某个位置
  62.         String realPath = getServletContext().getRealPath("/image/OIP.jpg");
  63.         File file = new File(realPath);
  64.     }
  66.     private void processFormField(FileItem item) {
  67.         String name = item.getFieldName();
  68.         String value = item.getString();
  69.         System.out.println("name:" + name);
  70.         System.out.println("value:" + value);
  71.     }
  73.     private void processUploadedFile(FileItem item) {
  74.         String fieldName = item.getFieldName();
  75.         String fileName = item.getName();
  76.         String contentType = item.getContentType();
  77.         boolean isInMemory = item.isInMemory();
  78.         long sizeInBytes = item.getSize();
  79.         System.out.println("fieldName:" + fieldName);
  80.         System.out.println("fileName:" + fileName);
  81.         System.out.println("contentType:" + contentType);
  82.         System.out.println("isInMemory:" + isInMemory);
  83.         System.out.println("sizeBytes:" + sizeInBytes);
  85.         String image = getServletContext().getRealPath("image");
  86.         String realPath = image + "/" + fileName;
  87.         File file = new File(realPath);
  88.         try {
  89.             item.write(file);
  90.         } catch (Exception e) {
  91.             e.printStackTrace();
  92.         }
  93.     }
  94. }

image.png
image.pngimage.png
又失败了，嘤嘤嘤~~~~