Java下http下载文件客户端和上传文件客户端实例代码

package javadownload; 
import java.io.ByteArrayOutputStream; 
import java.io.File; 
import java.io.FileOutputStream; 
import java.io.InputStream; 
import java.net.HttpURLConnection; 
import java.net.URL; 
/** 
 * @说明 导出虚拟机 
 * @author wxt 
 * @version 1.0 
 * @since 
 */ 
public class GetVM { 
  /** 
   * 测试 
   * @param args 
   */ 
  public static void main(String[] args) { 
    String url = "http://192.168.5.102:8845/xx"; 
    byte[] btImg = getVMFromNetByUrl(url); 
    if(null != btImg && btImg.length > 0){ 
      System.out.println("读取到：" + btImg.length + " 字节"); 
      String fileName = "ygserver"; 
      writeImageToDisk(btImg, fileName); 
    }else{ 
      System.out.println("没有从该连接获得内容"); 
    } 
  } 
  /** 
   * 将vm 写入到磁盘 
   * @param vm 数据流 
   * @param fileName 文件保存时的名称 
   */ 
  public static void writeImageToDisk(byte[] vm, String fileName){ 
    try { 
      File file = new File("./" + fileName); 
      FileOutputStream fops = new FileOutputStream(file); 
      fops.write(vm); 
      fops.flush(); 
      fops.close(); 
      System.out.println("下载完成"); 
    } catch (Exception e) { 
      e.printStackTrace(); 
    } 
  } 
  /** 
   * 根据地址获得数据的字节流 
   * @param strUrl 网络连接地址 
   * @return 
   */ 
  public static byte[] getVMFromNetByUrl(String strUrl){ 
    try { 
      URL url = new URL(strUrl); 
      HttpURLConnection cOnn= (HttpURLConnection)url.openConnection(); 
      conn.setRequestMethod("GET"); 
      conn.setConnectTimeout(5 * 1000); 
      InputStream inStream = conn.getInputStream();//通过输入流获取数据 
      byte[] btImg = readInputStream(inStream);//得到的二进制数据 
      return btImg; 
    } catch (Exception e) { 
      e.printStackTrace(); 
    } 
    return null; 
  } 
  /** 
   * 从输入流中获取数据 
   * @param inStream 输入流 
   * @return 
   * @throws Exception 
   */ 
  public static byte[] readInputStream(InputStream inStream) throws Exception{ 
    ByteArrayOutputStream outStream = new ByteArrayOutputStream(); 
    byte[] buffer = new byte[1024]; 
    int len = 0; 
    while( (len=inStream.read(buffer)) != -1 ){ 
      outStream.write(buffer, 0, len); 
    } 
    inStream.close(); 
    return outStream.toByteArray(); 
  } 
} 

package javadownload; 
import java.io.ByteArrayOutputStream; 
import java.io.File; 
import java.io.FileOutputStream; 
import java.io.InputStream; 
import java.net.HttpURLConnection; 
import java.net.URL; 
/** 
 * @说明 导出虚拟机 
 * @author wxt 
 * @version 1.0 
 * @since 
 */ 
public class GetBigFile { 
  /** 
   * 测试 
   * @param args 
   */ 
  public static void main(String[] args) { 
    String url = "http://192.168.5.76:8080/export&＃63;uuid=123"; 
    String fileName="yserver";  
    getVMFromNetByUrl(url,fileName); 
  } 
  /** 
   * 根据地址获下载文件 
   * @param strUrl 网络连接地址 
   * @param fileName 下载文件的存储名称 
   */ 
  public static void getVMFromNetByUrl(String strUrl,String fileName){ 
    try { 
      URL url = new URL(strUrl); 
      HttpURLConnection cOnn= (HttpURLConnection)url.openConnection(); 
      conn.setRequestMethod("GET"); 
      conn.setConnectTimeout(5 * 1000); 
      InputStream inStream = conn.getInputStream();//通过输入流获取数据 
      byte[] buffer = new byte[4096]; 
      int len = 0; 
      File file = new File("./" + fileName); 
      FileOutputStream fops = new FileOutputStream(file); 
      while( (len=inStream.read(buffer)) != -1 ){ 
        fops.write(buffer, 0, len); 
      } 
      fops.flush(); 
      fops.close();   
    } catch (Exception e) { 
      e.printStackTrace(); 
    } 
  } 
} 

package javadownload; 
import java.io.DataInputStream; 
import java.io.DataOutputStream; 
import java.io.File; 
import java.io.FileInputStream; 
import java.io.IOException; 
import java.io.OutputStream; 
import java.net.HttpURLConnection; 
import java.net.URL; 
public class FileUpload { 
  /** 
   * 发送请求 
   * 
   * @param url 
   *      请求地址 
   * @param filePath 
   *      文件在服务器保存路径（这里是为了自己测试方便而写，可以将该参数去掉） 
   * @return 
   * @throws IOException 
   */ 
  public int send(String url, String filePath) throws IOException { 
    File file = new File(filePath); 
    if (!file.exists() || !file.isFile()) { 
      return -1; 
    } 
    /** 
     * 第一部分 
     */ 
    URL urlObj = new URL(url); 
    HttpURLConnection con = (HttpURLConnection) urlObj.openConnection(); 
    /** 
     * 设置关键值 
     */ 
    con.setRequestMethod("POST"); // 以Post方式提交表单，默认get方式 
    con.setDoInput(true); 
    con.setDoOutput(true); 
    con.setUseCaches(false); // post方式不能使用缓存 
    // 设置请求头信息 
    con.setRequestProperty("Connection", "close");//Keep-Alive 
    con.setRequestProperty("Charset", "UTF-8"); 
    // 设置边界 
    String BOUNDARY = "----------" + System.currentTimeMillis(); 
    con.setRequestProperty("Content-Type", "multipart/form-data; boundary=" 
        + BOUNDARY); 
    // 请求正文信息 
    // 第一部分： 
    StringBuilder sb = new StringBuilder(); 
    sb.append("--"); // ////////必须多两道线 
    sb.append(BOUNDARY); 
    sb.append("\r\n"); 
    sb.append("Content-Disposition: form-data;name=\"file_name\";filename=\"" 
        + file.getName() + "\"\r\n"); 
    sb.append("Content-Type:application/octet-stream\r\n\r\n"); 
    sb.append("Connection:close\r\n\r\n"); 
    byte[] head = sb.toString().getBytes("utf-8"); 
    // 获得输出流 
    OutputStream out = new DataOutputStream(con.getOutputStream()); 
    out.write(head); 
    // 文件正文部分 
    DataInputStream in = new DataInputStream(new FileInputStream(file)); 
    int bytes = 0; 
    byte[] bufferOut = new byte[1024]; 
    while ((bytes = in.read(bufferOut)) != -1) { 
      out.write(bufferOut, 0, bytes); 
    } 
    in.close(); 
    // 结尾部分 
    byte[] foot = ("\r\n--" + BOUNDARY + "--\r\n").getBytes("utf-8");// 定义最后数据分隔线 
    out.write(foot); 
    out.flush(); 
    out.close(); 
    /** 
     * 读取服务器响应，必须读取,否则提交不成功 
     */ 
    return con.getResponseCode(); 
    /** 
     * 下面的方式读取也是可以的 
     */ 
    // try { 
    // // 定义BufferedReader输入流来读取URL的响应 
    // BufferedReader reader = new BufferedReader(new InputStreamReader( 
    // con.getInputStream())); 
    // String line = null; 
    // while ((line = reader.readLine()) != null) { 
    // System.out.println(line); 
    // } 
    // } catch (Exception e) { 
    // System.out.println("发送POST请求出现异常！" + e); 
    // e.printStackTrace(); 
    // } 
  } 
  public static void main(String[] args) throws IOException { 
    FileUpload up = new FileUpload(); 
    System.out.println(up.send("http://192.168.5.102:8845/xx", 
        "./vif.xml")); 
    ; 
  } 
}