java 实现 http 文件下载

package com.easemob.server.example.httpclient.utils;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLDecoder;

public class HttpUtils {

    /** * LOCAL_PATH 文件存储的位置 * fileUrl 待下载文件地址 * type 文件类型 jpg,png,mp3... * @return */
     public static String FileDown(String LOCAL_PATH,String fileUrl,String type){

         InputStream in=null;
          OutputStream out=null;
          HttpURLConnection conn=null;
          String fileName=null;
          try {
           //初始化连接
           URL url=new URL(fileUrl);
           conn = (HttpURLConnection) url.openConnection();
           conn.setDoInput(true);
           conn.setDoOutput(true);

           //获取文件名
           String disposition=conn.getHeaderField("Content-Disposition");
           if(disposition!=null&&!"".equals(disposition)){
            //从头中获取文件名
            fileName=disposition.split(";")[1].split("=")[1].replaceAll("\"","");
           }else{
            //从地址中获取文件名
            fileName=fileUrl.substring(fileUrl.lastIndexOf("/")+1);
           }

           if(fileName!=null&&!"".equals(fileName)){
            //文件名解码
            fileName=URLDecoder.decode(fileName, "utf-8")+".jpg";
           }else{
            //如果无法获取文件名，则随机生成一个
            fileName="file_"+(int)(Math.random()*10)+type;
           }

           //读取数据
           if(conn.getResponseCode()==HttpURLConnection.HTTP_OK){
            byte[] buffer=new byte[2048];
            in = conn.getInputStream();
            out=new FileOutputStream(new File(LOCAL_PATH,fileName));
            int count=0;
            int finished=0;
            int size=conn.getContentLength();
            while((count=in.read(buffer))!=-1){
             if(count!=0){
              out.write(buffer,0,count);
              finished+=count;
             // System.out.printf("---->%1$.2f%%\n",(double)finished/size*100);
             }else{
              break;
             }
            }
           }
          } catch (MalformedURLException e) {
           e.printStackTrace();
          } catch (IOException e) {
           e.printStackTrace();
          }finally{
           try {
            out.close();
            in.close();
            conn.disconnect();
           } catch (IOException e) {
            e.printStackTrace();
           }
          }

         return fileName;
     }

     public static void main(String[] args) {
      //待下载文件地址
      String fileUrl="http://182.92.228.160:80/otrue-cn/healthmanager/chatfiles/22ecda70-ad43-11e5-9531-d7e3b2ec0d8e";
       String LOCAL_PATH="E:/ceshi/";
       String type="jpg";
       String filename=FileDown(LOCAL_PATH, fileUrl,type);
       System.out.println(filename);
     }
}