利用HttpClient进行http文件上传

1. java.lang.NoClassDefFoundError: org/apache/commons/codec/DecoderException 的解决办法

用cacuts做单元测试servlet时候总报这个错误，原来是bin文件缺少了要一个包commons-codec-1.x.jar

网络编程HttpClient 要一个包commons-codec-1.x.jar
HttpClient 用到了 Apache Jakarta common 下的子项目 codec，你可以从这个地址http://commons.apache.org/downloads/download_codec.cgi 下载到最新的 common codec，从下载后的压缩包中取出 commons-codec-1.x.jar 加到 CLASSPATH 中

commons-codec-1.4-bin.zip

应用程序部分：

注意：要载入commons-httpclient-3.1.jar commons-codec.jar commons-logging.jar这三个包

import java.io.File;

import org.apache.commons.httpclient.HttpClient;
import org.apache.commons.httpclient.HttpStatus;
import org.apache.commons.httpclient.methods.PostMethod;
import org.apache.commons.httpclient.methods.multipart.FilePart;
import org.apache.commons.httpclient.methods.multipart.MultipartRequestEntity;
import org.apache.commons.httpclient.methods.multipart.Part;

public class Hclient
{
public static void main(String args[])
{
   String targetURL = null;// TODO 指定URL
   File targetFile = null;// TODO 指定上传文件
  
   targetFile = new File("1.mp3");
   targetURL = "http://localhost:8080/test/tt"; //servleturl
   PostMethod filePost = new PostMethod(targetURL);  //若没有commons-codec-1.4-bin.zip, 这里将会出错
  
   try
   {

    //通过以下方法可以模拟页面参数提交
    //filePost.setParameter("name", "中文");
    //filePost.setParameter("pass", "1234");

   Part[] parts = { new FilePart(targetFile.getName(), targetFile) };
    filePost.setRequestEntity(new MultipartRequestEntity(parts,filePost.getParams()));
    HttpClient client = new HttpClient();
    client.getHttpConnectionManager().getParams().setConnectionTimeout(5000);
    int status = client.executeMethod(filePost);
    if (status == HttpStatus.SC_OK)
    {
     System.out.println("上传成功");
     // 上传成功
    }
    else
    {
     System.out.println("上传失败");
     // 上传失败
    }
   }
   catch (Exception ex)
   {
    ex.printStackTrace();
   }
   finally
   {
    filePost.releaseConnection();
   }
}
}

 

servlet部分：

注意：需求载入commons-fileupload-1.2.1.jar commons-io.jar这两个包

package servlet;

import java.io.File;
import java.io.IOException;
import java.util.Iterator;
import java.util.List;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

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

public class TestServlets extends HttpServlet
{
private String uploadPath = "D:\\temp"; // 上传文件的目录
    private String tempPath = "d:\\temp\\buffer\\"; // 临时文件目录
    File tempPathFile;
   
    public void init() throws ServletException {
        File uploadFile = new File(uploadPath);
        if (!uploadFile.exists()) {
            uploadFile.mkdirs();
        }
        File tempPathFile = new File(tempPath);
         if (!tempPathFile.exists()) {
            tempPathFile.mkdirs();
        }
     }

public void doPost(HttpServletRequest request, HttpServletResponse response)
    throws ServletException, IOException
{
   try
   {
    // Create a factory for disk-based file items
    DiskFileItemFactory factory = new DiskFileItemFactory();
    // Set factory constraints
    factory.setSizeThreshold(4096); // 设置缓冲区大小，这里是4kb
    factory.setRepository(tempPathFile);// 设置缓冲区目录
    // Create a new file upload handler
    ServletFileUpload upload = new ServletFileUpload(factory);
    // Set overall request size constraint
    upload.setSizeMax(4194304); // 设置最大文件尺寸，这里是4MB
    List<FileItem> items = upload.parseRequest(request);// 得到所有的文件
    Iterator<FileItem> i = items.iterator();
    while (i.hasNext())
    {
     FileItem fi = (FileItem) i.next();
     String fileName = fi.getName();
     if (fileName != null)
     {
      File fullFile = new File(fi.getName());
      File savedFile = new File(uploadPath, fullFile.getName());
      fi.write(savedFile);
     }
    }
    System.out.print("upload succeed");
   }
   catch (Exception e)
   {
    System.out.println(e.getMessage());
    // 可以跳转出错页面
    e.printStackTrace();
   }
}
}

在web.xml中添加映射，就可以实现应用程序上传文件到servlet的功能了。

下面是一个例子的war文件：

fileUpload.zip

解压之后会先得到一个war，密码FileUpload123