【JAVA】通过HttpURLConnection 上传和下载文件（二）

HttpURLConnection文件上传

　　HttpURLConnection采用模拟浏览器上传的数据格式，上传给服务器

　　上传代码如下：

•  package com.util;
  
   import java.io.BufferedInputStream;
   import java.io.BufferedReader;
   import java.io.DataOutputStream;
   import java.io.File;
   import java.io.FileInputStream;
   import java.io.FileOutputStream;
   import java.io.IOException;
   import java.io.InputStream;
   import java.io.InputStreamReader;
   import java.io.OutputStream;
   import java.io.OutputStreamWriter;
   import java.net.HttpURLConnection;
   import java.net.MalformedURLException;
   import java.net.URL;
   import java.net.URLConnection;
   import java.util.Iterator;
   import java.util.Map;
  
   /**
    * Java原生的API可用于发送HTTP请求，即java.net.URL、java.net.URLConnection，这些API很好用、很常用，
    * 但不够简便；
    *
    * 1.通过统一资源定位器（java.net.URL）获取连接器（java.net.URLConnection） 2.设置请求的参数 3.发送请求
    * 4.以输入流的形式获取返回内容 5.关闭输入流
    *
    * @author H__D
    *
    */
   public class HttpConnectionUtil {
  
       /**
        * 多文件上传的方法
        *
        * @param actionUrl：上传的路径
        * @param uploadFilePaths：需要上传的文件路径，数组
        * @return
        */
       @SuppressWarnings("finally")
       public static String uploadFile(String actionUrl, String[] uploadFilePaths) {
           String end = "\r\n";
           String twoHyphens = "--";
           String boundary = "*****";
  
           DataOutputStream ds = null;
           InputStream inputStream = null;
           InputStreamReader inputStreamReader = null;
           BufferedReader reader = null;
           StringBuffer resultBuffer = new StringBuffer();
           String tempLine = null;
  
           try {
               // 统一资源
               URL url = new URL(actionUrl);
               // 连接类的父类，抽象类
               URLConnection urlConnection = url.openConnection();
               // http的连接类
               HttpURLConnection httpURLConnection = (HttpURLConnection) urlConnection;
  
               // 设置是否从httpUrlConnection读入，默认情况下是true;
               httpURLConnection.setDoInput(true);
               // 设置是否向httpUrlConnection输出
               httpURLConnection.setDoOutput(true);
               // Post 请求不能使用缓存
               httpURLConnection.setUseCaches(false);
               // 设定请求的方法，默认是GET
               httpURLConnection.setRequestMethod("POST");
               // 设置字符编码连接参数
               httpURLConnection.setRequestProperty("Connection", "Keep-Alive");
               // 设置字符编码
               httpURLConnection.setRequestProperty("Charset", "UTF-8");
               // 设置请求内容类型
               httpURLConnection.setRequestProperty("Content-Type", "multipart/form-data;boundary=" + boundary);
  
               // 设置DataOutputStream
               ds = new DataOutputStream(httpURLConnection.getOutputStream());
               for (int i = 0; i < uploadFilePaths.length; i++) {
                   String uploadFile = uploadFilePaths[i];
                   String filename = uploadFile.substring(uploadFile.lastIndexOf("//") + 1);
                   ds.writeBytes(twoHyphens + boundary + end);
                   ds.writeBytes("Content-Disposition: form-data; " + "name=\"file" + i + "\";filename=\"" + filename
                           + "\"" + end);
                   ds.writeBytes(end);
                   FileInputStream fStream = new FileInputStream(uploadFile);
                   int bufferSize = 1024;
                   byte[] buffer = new byte[bufferSize];
                   int length = -1;
                   while ((length = fStream.read(buffer)) != -1) {
                       ds.write(buffer, 0, length);
                   }
                   ds.writeBytes(end);
                   /* close streams */
                   fStream.close();
               }
               ds.writeBytes(twoHyphens + boundary + twoHyphens + end);
               /* close streams */
               ds.flush();
               if (httpURLConnection.getResponseCode() >= 300) {
                   throw new Exception(
                           "HTTP Request is not success, Response code is " + httpURLConnection.getResponseCode());
               }
  
               if (httpURLConnection.getResponseCode() == HttpURLConnection.HTTP_OK) {
                   inputStream = httpURLConnection.getInputStream();
                   inputStreamReader = new InputStreamReader(inputStream);
                   reader = new BufferedReader(inputStreamReader);
                   tempLine = null;
                   resultBuffer = new StringBuffer();
                   while ((tempLine = reader.readLine()) != null) {
                       resultBuffer.append(tempLine);
                       resultBuffer.append("\n");
                   }
               }
  
           } catch (Exception e) {
               // TODO Auto-generated catch block
               e.printStackTrace();
           } finally {
               if (ds != null) {
                   try {
                       ds.close();
                   } catch (IOException e) {
                       // TODO Auto-generated catch block
                       e.printStackTrace();
                   }
               }
               if (reader != null) {
                   try {
                       reader.close();
                   } catch (IOException e) {
                       // TODO Auto-generated catch block
                       e.printStackTrace();
                   }
               }
               if (inputStreamReader != null) {
                   try {
                       inputStreamReader.close();
                   } catch (IOException e) {
                       // TODO Auto-generated catch block
                       e.printStackTrace();
                   }
               }
               if (inputStream != null) {
                   try {
                       inputStream.close();
                   } catch (IOException e) {
                       // TODO Auto-generated catch block
                       e.printStackTrace();
                   }
               }
  
               return resultBuffer.toString();
           }
       }
  
       public static void main(String[] args) {
  
           // 上传文件测试
            String str = uploadFile("http://127.0.0.1:8080/image/image.do",new String[] { "/Users//H__D/Desktop//1.png","//Users/H__D/Desktop/2.png" });
            System.out.println(str);
  
       }
  
   }

  uploadFile

HttpURLConnection文件下载

　　下载代码如下：

•  package com.util;
  
   import java.io.BufferedInputStream;
   import java.io.BufferedReader;
   import java.io.DataOutputStream;
   import java.io.File;
   import java.io.FileInputStream;
   import java.io.FileOutputStream;
   import java.io.IOException;
   import java.io.InputStream;
   import java.io.InputStreamReader;
   import java.io.OutputStream;
   import java.io.OutputStreamWriter;
   import java.net.HttpURLConnection;
   import java.net.MalformedURLException;
   import java.net.URL;
   import java.net.URLConnection;
   import java.util.Iterator;
   import java.util.Map;
  
   /**
    * Java原生的API可用于发送HTTP请求，即java.net.URL、java.net.URLConnection，这些API很好用、很常用，
    * 但不够简便；
    *
    * 1.通过统一资源定位器（java.net.URL）获取连接器（java.net.URLConnection） 2.设置请求的参数 3.发送请求
    * 4.以输入流的形式获取返回内容 5.关闭输入流
    *
    * @author H__D
    *
    */
   public class HttpConnectionUtil {
  
       /**
        *
        * @param urlPath
        *            下载路径
        * @param downloadDir
        *            下载存放目录
        * @return 返回下载文件
        */
       public static File downloadFile(String urlPath, String downloadDir) {
           File file = null;
           try {
               // 统一资源
               URL url = new URL(urlPath);
               // 连接类的父类，抽象类
               URLConnection urlConnection = url.openConnection();
               // http的连接类
               HttpURLConnection httpURLConnection = (HttpURLConnection) urlConnection;
               // 设定请求的方法，默认是GET
               httpURLConnection.setRequestMethod("POST");
               // 设置字符编码
               httpURLConnection.setRequestProperty("Charset", "UTF-8");
               // 打开到此 URL 引用的资源的通信链接（如果尚未建立这样的连接）。
               httpURLConnection.connect();
  
               // 文件大小
               int fileLength = httpURLConnection.getContentLength();
  
               // 文件名
               String filePathUrl = httpURLConnection.getURL().getFile();
               String fileFullName = filePathUrl.substring(filePathUrl.lastIndexOf(File.separatorChar) + 1);
  
               System.out.println("file length---->" + fileLength);
  
               URLConnection con = url.openConnection();
  
               BufferedInputStream bin = new BufferedInputStream(httpURLConnection.getInputStream());
  
               String path = downloadDir + File.separatorChar + fileFullName;
               file = new File(path);
               if (!file.getParentFile().exists()) {
                   file.getParentFile().mkdirs();
               }
               OutputStream out = new FileOutputStream(file);
               int size = 0;
               int len = 0;
               byte[] buf = new byte[1024];
               while ((size = bin.read(buf)) != -1) {
                   len += size;
                   out.write(buf, 0, size);
                   // 打印下载百分比
                   // System.out.println("下载了-------> " + len * 100 / fileLength +
                   // "%\n");
               }
               bin.close();
               out.close();
           } catch (MalformedURLException e) {
               // TODO Auto-generated catch block
               e.printStackTrace();
           } catch (IOException e) {
               // TODO Auto-generated catch block
               e.printStackTrace();
           } finally {
               return file;
           }
  
       }
  
       public static void main(String[] args) {
  
           // 下载文件测试
           downloadFile("http://localhost:8080/images/1467523487190.png", "/Users/H__D/Desktop");
  
       }
  
   }

  downloadFile