这里用apache的HttpClient4.3模拟文件上传，上传到一个java servlet，然后用servlet解析，把上传文件放到服务器目录下

下面这个java应用，往一个java servlet中提交了一个文件，和几个普通表单属性

package com.test.httpClient;import java.io.File;import java.io.IOException;import java.nio.charset.Charset;import org.apache.http.Consts;import org.apache.http.HttpEntity;import org.apache.http.client.methods.CloseableHttpResponse;import org.apache.http.client.methods.HttpPost;import org.apache.http.entity.ContentType;import org.apache.http.entity.mime.MultipartEntityBuilder;import org.apache.http.entity.mime.content.FileBody;import org.apache.http.entity.mime.content.StringBody;import org.apache.http.impl.client.CloseableHttpClient;import org.apache.http.impl.client.HttpClients;import org.apache.http.util.EntityUtils;public class ClientMultipartFormPost {	/**	 * 这个例子展示了如何执行请求包含一个多部分编码的实体	 * 模拟表单提交	 * @throws IOException 	 */	public static void main(String[] args) throws IOException {		CloseableHttpClient httpClient = HttpClients.createDefault();		try{			//要上传的文件的路径			String filePath = "D:\\my_shutdown.log";			//把一个普通参数和文件上传给下面这个地址    是一个servlet			HttpPost httpPost = new HttpPost("http://localhost:80/testjs/servlet/UploadServlet");			//把文件转换成流对象FileBody			FileBody bin = new FileBody(new File(filePath));			//普通字段  重新设置了编码方式			StringBody comment = new StringBody("这里是一个评论", ContentType.create("text/plain", Consts.UTF_8));			//StringBody comment = new StringBody("这里是一个评论", ContentType.TEXT_PLAIN);						StringBody name = new StringBody("王五", ContentType.create("text/plain", Consts.UTF_8));			StringBody password = new StringBody("123456", ContentType.create("text/plain", Consts.UTF_8));			            HttpEntity reqEntity = MultipartEntityBuilder.create()            .addPart("media", bin)//相当于
                .addPart("comment", comment)            .addPart("name", name)//相当于
    
                 .addPart("password", password)            .build();                        httpPost.setEntity(reqEntity);                        System.out.println("发起请求的页面地址 " + httpPost.getRequestLine());            //发起请求   并返回请求的响应            CloseableHttpResponse response = httpClient.execute(httpPost);            try {                System.out.println("----------------------------------------");                //打印响应状态                System.out.println(response.getStatusLine());                //获取响应对象                HttpEntity resEntity = response.getEntity();                if (resEntity != null) {                	//打印响应长度                    System.out.println("Response content length: " + resEntity.getContentLength());                    //打印响应内容                    System.out.println(EntityUtils.toString(resEntity,Charset.forName("UTF-8")));                }                //销毁                EntityUtils.consume(resEntity);            } finally {                response.close();            }		}finally{			httpClient.close();		}	}}
    

用于接收的java servlet  用到了apache的common-fileupload来解析请求main中提交的参数

    
     package com.vincente.test.servlet;      import java.io.BufferedReader;  import java.io.DataInputStream;  import java.io.DataOutputStream;  import java.io.File;  import java.io.FileInputStream;  import java.io.IOException;  import java.io.InputStream;  import java.io.InputStreamReader;  import java.io.OutputStream;  import java.io.PrintWriter;  import java.net.HttpURLConnection;  import java.net.URL;  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.FileItemFactory;  import org.apache.commons.fileupload.FileUploadException;  import org.apache.commons.fileupload.disk.DiskFileItemFactory;  import org.apache.commons.fileupload.servlet.ServletFileUpload;      public class UploadServlet extends HttpServlet {          public void doGet(HttpServletRequest request, HttpServletResponse response)              throws ServletException, IOException {        }        public void doPost(HttpServletRequest request, HttpServletResponse response)              throws ServletException, IOException {          request.setCharacterEncoding("utf-8");          response.setCharacterEncoding("utf-8");                    //利用apache的common-upload上传组件来进行  来解析获取到的流文件                    //把上传来的文件放在这里          String uploadPath = getServletContext().getRealPath("/upload");//获取文件路径                     //检测是不是存在上传文件          // Check that we have a file upload request          boolean isMultipart = ServletFileUpload.isMultipartContent(request);                    if(isMultipart){                            DiskFileItemFactory factory = new DiskFileItemFactory();              //指定在内存中缓存数据大小,单位为byte,这里设为1Mb              factory.setSizeThreshold(1024*1024);              //设置一旦文件大小超过getSizeThreshold()的值时数据存放在硬盘的目录               factory.setRepository(new File("D://temp"));              // Create a new file upload handler              ServletFileUpload upload = new ServletFileUpload(factory);              // 指定单个上传文件的最大尺寸,单位:字节，这里设为5Mb                upload.setFileSizeMax(5 * 1024 * 1024);                //指定一次上传多个文件的总尺寸,单位:字节，这里设为10Mb                upload.setSizeMax(10 * 1024 * 1024);                 upload.setHeaderEncoding("UTF-8"); //设置编码，因为我的jsp页面的编码是utf-8的                             List
     
       items = null;                            try {                  // 解析request请求                  items = upload.parseRequest(request);              } catch (FileUploadException e) {                  e.printStackTrace();              }              if(items!=null){                  //把上传文件放到服务器的这个目录下                  if (!new File(uploadPath).isDirectory()){                        new File(uploadPath).mkdirs(); //选定上传的目录此处为当前目录，没有则创建                    }                   //解析表单项目                  // Process the uploaded items                  Iterator
      
        iter = items.iterator();                  while (iter.hasNext()) {                      FileItem item = iter.next();                      //如果是普通表单属性                      if (item.isFormField()) {                          //
       
                                  String name = item.getFieldName();//相当于input的name属性                          String value = item.getString();//input的value属性                          System.out.println("属性:"+name+" 属性值:"+value);                      }                      //如果是上传文件                      else {                          //属性名                          String fieldName = item.getFieldName();                          //上传文件路径                          String fileName = item.getName();                          fileName = fileName.substring(fileName.lastIndexOf("/")+1);// 获得上传文件的文件名                          try {                              item.write(new File(uploadPath,fileName));                          } catch (Exception e) {                              e.printStackTrace();                          }                          //给请求页面返回响应                          response.getWriter().println("文件上传成功! 文件名是:"+fileName);                      }                  }              }          }                
        
            }  
         
          
           
            main中的执行结果：  发起请求的页面地址 POST http://localhost:80/testjs/servlet/UploadServlet HTTP/1.1  ----------------------------------------  HTTP/1.1 200 OK  Response content length: 50  文件上传成功! 文件名是:my_shutdown.log      tomcat中的执行结果：  属性:comment 属性值:这里是一个评论  属性:name 属性值:王五  属性:password 属性值:123456