android文件上传到服务器

/**
* 通过拼接的方式构造请求内容，实现参数传输以及文件传输
* @param actionUrl
* @param params
* @param files
* @return
* @throws IOException
*/
public static String post(String actionUrl, Map<String, String> params,
Map<String, File> files) throws IOException {

String BOUNDARY = java.util.UUID.randomUUID().toString();
String PREFIX = "--" , LINEND = "\r\n";
String MULTIPART_FROM_DATA = "multipart/form-data";
String CHARSET = "UTF-8";

URL uri = new URL(actionUrl);
HttpURLConnection conn = (HttpURLConnection) uri.openConnection();
conn.setReadTimeout(5 * 1000); // 缓存的最长时间
conn.setDoInput(true);// 允许输入
conn.setDoOutput(true);// 允许输出
conn.setUseCaches(false); // 不允许使用缓存
conn.setRequestMethod("POST");
conn.setRequestProperty("connection", "keep-alive");
conn.setRequestProperty("Charsert", "UTF-8");
conn.setRequestProperty("Content-Type", MULTIPART_FROM_DATA + ";boundary=" + BOUNDARY);

// 首先组拼文本类型的参数
StringBuilder sb = new StringBuilder();
for (Map.Entry<String, String> entry : params.entrySet()) {
sb.append(PREFIX);
sb.append(BOUNDARY);
sb.append(LINEND);
sb.append("Content-Disposition: form-data; name=\"" + entry.getKey() + "\"" + LINEND);
sb.append("Content-Type: text/plain; charset=" + CHARSET+LINEND);
sb.append("Content-Transfer-Encoding: 8bit" + LINEND);
sb.append(LINEND);
sb.append(entry.getValue());
sb.append(LINEND);
}

DataOutputStream outStream = new DataOutputStream(conn.getOutputStream());
outStream.write(sb.toString().getBytes());
// 发送文件数据
if(files!=null){
int i = 0;
for (Map.Entry<String, File> file: files.entrySet()) {
StringBuilder sb1 = new StringBuilder();
sb1.append(PREFIX);
sb1.append(BOUNDARY);
sb1.append(LINEND);
sb1.append("Content-Disposition: form-data; name=\"file"+(i++)+"\"; filename=\""+file.getKey()+"\""+LINEND);
sb1.append("Content-Type: application/octet-stream; charset="+CHARSET+LINEND);
sb1.append(LINEND);
outStream.write(sb1.toString().getBytes());

InputStream is = new FileInputStream(file.getValue());
byte[] buffer = new byte[1024];
int len = 0;
while ((len = is.read(buffer)) != -1) {
outStream.write(buffer, 0, len);
}

is.close();
outStream.write(LINEND.getBytes());
}
}

//请求结束标志
byte[] end_data = (PREFIX + BOUNDARY + PREFIX + LINEND).getBytes();
outStream.write(end_data);
outStream.flush();

//得到响应码
int res = conn.getResponseCode();
InputStream in = null;
if (res == 200) {
in = conn.getInputStream();
int ch;
StringBuilder sb2 = new StringBuilder();
while ((ch = in.read()) != -1) {
sb2.append((char) ch);
}
}
return in == null ? null : in.toString();
}

原帖链接： http://www.aslibra.com/blog/post/android-upload-files-to-server.php