Java doGet, doPost方法和文件上传实例代码

Java doGet, doPost方法和文件上传

index.html

TestServlet.Java

import org.apache.commons.fileupload.FileItem;
import org.apache.commons.fileupload.FileUploadException;
import org.apache.commons.fileupload.disk.DiskFileItemFactory;
import org.apache.commons.fileupload.servlet.ServletFileUpload;

import javax.servlet.ServletException;
import javax.servlet.ServletInputStream;
import javax.servlet.ServletOutputStream;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.IOException;
import java.net.URLDecoder;
import java.net.URLEncoder;
import java.util.Enumeration;
import java.util.List;


@WebServlet(name = "TestServlet")
public class TestServlet extends HttpServlet {
  private File root_upload;
  public TestServlet() {
    root_upload = new File("C:/temp");
    if (!root_upload.exists()) {
      root_upload.mkdirs();
    }
  }


  //两种链接方式 doPost doGet
  protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

    response.setCharacterEncoding("UTF-8");
    request.setCharacterEncoding("UTF-8");
    ServletOutputStream os = response.getOutputStream();
    StringBuilder builder = new StringBuilder();

    builder.append("");
    builder.append("");
    builder.append("  ");
    builder.append("  ");
    builder.append("");
    builder.append("");

    Enumeration names = request.getHeaderNames();
    while (names.hasMoreElements()) {
      String name = names.nextElement();
      builder.append(name)
   .append(":")
   .append(request.getHeader(name))
   .append("
");
    }

    DiskFileItemFactory factory = new DiskFileItemFactory();
    factory.setSizeThreshold(10);//设置未保存在临时路径的最大值
    factory.setRepository(new File("C:/temp/temp"));//超过上述最大值后保存的临时路径
    ServletFileUpload upload = new ServletFileUpload(factory);
    try {
      List list = upload.parseRequest(request);//上传的文件列表

      for (FileItem item : list) {
 builder.append(item.getFieldName())
     .append(":")
     .append(item.isFormField() ? item.getString() : item.getName())//判断是不是属性, 如果是属性, 就
     .append("
");
 if (!item.isFormField()) {
   File file = new File(root_upload, item.getName());
   builder.append(file.getAbsolutePath()).append("
");
   item.write(file);
 }
      }

    } catch (FileUploadException e) {
      e.printStackTrace();
    } catch (Exception e) {
      e.printStackTrace();
    }


    //可以从输入流中读取数据
//    ServletInputStream is = request.getInputStream();
//    byte[] buffer = new byte[8192];
//    int len ;
//    ByteArrayOutputStream bos= new ByteArrayOutputStream();
//    while ((len = is.read(buffer)) != -1) {
//      bos.write(buffer, 0, len);
//    }
//    builder.append("InputStream: ")
// .append(bos.toString("UTF-8"))
// .append("
");

//    builder.append("Post的请求参数").append("
");
//
//    Enumeration parameterNames = request.getParameterNames();
//    while (parameterNames.hasMoreElements()) {
//      String name = parameterNames.nextElement();
//      builder.append(name)
//   .append(":")
//   .append(request.getParameter(name))
//   .append("
");
//    }

    //接收来自浏览器的文件,

    os.write(builder.toString().getBytes("UTF-8"));
    //参数列表: 待转码的字符串, 字符编码
    URLEncoder.encode("&", "UTF-8");
    URLDecoder.decode("%26", "UTF-8");
    builder.append("");
    builder.append("");

  }

  protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    doPost(request, response);
  }
}

web.xml

  
    TestServlet
    org.lulu.learn.TestServlet
  
  
    TestServlet
    /test
  

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