HttpURLConnection发送中文乱码问题解决

/**

 * 发送http POST请求
 *
 * @param
 * @return 远程响应结果
 */
public static String sendPost(String u, String json) throws Exception {
    StringBuffer sbf = new StringBuffer();
    try {
        URL url = new URL(u);
        HttpURLConnection connection = (HttpURLConnection) url.openConnection();
        connection.setDoInput(true);
        connection.setDoOutput(true);
        connection.setRequestMethod("POST");
        connection.setUseCaches(false);
        connection.setInstanceFollowRedirects(true);
        connection.addRequestProperty("Content-Type", "application/json");
        connection.setRequestProperty("User-Agent", "Mozilla/4.0 (compatible; MSIE 5.0; Windows NT; DigExt)");
        connection.connect();
        DataOutputStream out = new DataOutputStream(connection.getOutputStream());
        if (!"".equals(json)) {
            //out.writeBytes(json);
            out.write(json.getBytes());
        }
        out.flush();
        out.close();

        BufferedReader reader = new BufferedReader(new InputStreamReader(connection.getInputStream()));
        String lines;
        while ((lines = reader.readLine()) != null) {
            lines = new String(lines.getBytes(), "utf-8");
            sbf.append(lines);
        }
        System.out.println(sbf);
        reader.close();
        // 断开连接
        connection.disconnect();
    } catch (IOException e) {
        e.printStackTrace();
        throw e;
    }
    return sbf.toString();
}

重点在于:替换out.writeBytes(json);为 out.write(json.getBytes());

原因为：out.writeBytes(json);该语句在转中文时候，已经变成乱码

public final void writeBytes(String s) throws IOException {
int len = s.length();
for (int i = 0 ; i < len ; i++) {
out.write((byte)s.charAt(i));
}
incCount(len);
}

因为java里的char类型是16位的，一个char可以存储一个中文字符，在将其转换为 byte后高8位会丢失，这样就无法将中文字符完整的输出到输出流中。所以在可能有中文字符输出的地方最好先将其转换为字节数组，然后再通过write写入流，