搞了老半天，也百度搜了好多教程，目的网页是GB2312编码的，回传经过遍历后变成GBK编码，然后在TextView中显示，汉字就出现了乱码情况。最终是在回传数据流的时候，定义编码方式就行。

public class htmlserver {

public static String gethtml(String path) throws Exception {

URL url = new URL(path);

HttpURLConnection cons = (HttpURLConnection) url.openConnection();

cons.setConnectTimeout(5 * 1000);

cons.setRequestMethod("GET");

if (cons.getResponseCode() == 200) {

InputStream ImStream = cons.getInputStream();

byte[] data = readInputStream(ImStream);

return new String(data,"GBK");

} else {

throw new Exception("连接失败");

}

}

public static byte[] readInputStream(InputStream ImStream) throws Exception {

ByteArrayOutputStream outStream = new ByteArrayOutputStream();

byte[] buffer = new byte[1024];

int len = 0;

while ((len = ImStream.read(buffer)) != -1) {

outStream.write(buffer, 0, len);

}

outStream.close();

ImStream.close();

return outStream.toByteArray();

}

}