JAVA实现文件上传

 1     public String startToUpload(String urlStr, File file,
 2             String uploadType) {
 3 
 4         HttpURLConnection conn = null;
 5         BufferedReader bufferedReader = null;
 6         InputStreamReader inputStreamReader = null;
 7         String BOUNDARY = "---------------------------"; // boundary就是request头和上传文件内容的分隔符
 8         try {
 9             URL url = new URL(urlStr);
10             conn = (HttpURLConnection) url.openConnection();
11             conn.setConnectTimeout(5000);
12             conn.setReadTimeout(30000);
13             conn.setDoOutput(true);
14             conn.setDoInput(true);
15             conn.setUseCaches(false);
16             conn.setRequestMethod("POST");
17             conn.setRequestProperty("Connection", "Keep-Alive");
18             conn.setRequestProperty("User-Agent",
19                     "Mozilla/5.0 (Windows; U; Windows NT 6.1; zh-CN; rv:1.9.2.6)");
20             conn.setRequestProperty("Content-Type",
21                     "multipart/form-data; boundary=" + BOUNDARY);
22 
23             OutputStream out = new DataOutputStream(conn.getOutputStream());
24 
25             String filename = file.getName();
26 
27             StringBuffer strBuf = new StringBuffer();
28             strBuf.append("\r\n").append("--").append(BOUNDARY).append("\r\n");
29             strBuf.append("Content-Disposition: form-data; name=\"file\"; filename=\""
30                     + filename + "\"\r\n");
31             strBuf.append("Content-Type:" + uploadType + "\r\n\r\n");
32 
33             out.write(strBuf.toString().getBytes());
34 
35             DataInputStream in = new DataInputStream(new FileInputStream(file));
36             int bytes = 0;
37             byte[] bufferOut = new byte[1024];
38             while ((bytes = in.read(bufferOut)) != -1) {
39                 out.write(bufferOut, 0, bytes);
40             }
41             in.close();
42 
43             byte[] endData = ("\r\n--" + BOUNDARY + "--\r\n").getBytes();
44             out.write(endData);
45             out.flush();
46             out.close();
47 
48             // 读取返回数据
49             StringBuffer strBuf2 = new StringBuffer();
50             inputStreamReader = new InputStreamReader(conn.getInputStream(),
51                     "UTF-8");
52             bufferedReader = new BufferedReader(inputStreamReader);
53             String line = null;
54             while ((line = bufferedReader.readLine()) != null) {
55                 strBuf2.append(line).append("\n");
56             }
57 
58             JSONObject jsonArray = JSONObject.fromObject(strBuf2.toString());
59 
60             boolean uploadSuccess = jsonArray.getBoolean("returnCode");
61 
62             if (uploadSuccess) {
63                 return "";
64             }
65 
66             urlStr = jsonArray.getString("resultMsg");
67         } catch (Exception e) {
68             e.printStackTrace();
69             return e.getMessage();
70         } finally {
71             try {
72                 if (conn != null) {
73                     conn.disconnect();
74                 }
75                 if (inputStreamReader != null) {
76                     inputStreamReader.close();
77                 }
78                 if (bufferedReader != null) {
79                     bufferedReader.close();
80                 }
81             } catch (IOException e) {
82                 e.printStackTrace();
83             }
84         }
85         return urlStr;
86     }
87