本文记录的是使用HttpURLConnection发送Get和Post请求的示例, 关于HttpURLConnection的使用请参考: JDK中URLConnection使用详解.

这里将发送请求的方法封装在HttpRequest的类中，使用HttpURLConnection发送Http的Get和Post请求需要引入下面的类:

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import java.io.BufferedReader;
import java.io.DataOutputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;

其中， 发送Get请求的方法如下:

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public static String sendGet(String url) {
    String responseBody = null;
    try {
        URL getUrl = new URL(url);
        HttpURLConnection urlConnection = (HttpURLConnection)getUrl
                    .openConnection();
        urlConnection.setRequestMethod("GET");
        urlConnection.connect();

        int respCode = urlConnection.getResponseCode();
        if (HttpURLConnection.HTTP_OK == respCode) {
            BufferedReader bufferedReader = new BufferedReader(
                    new InputStreamReader(urlConnection.getInputStream(), "UTF-8"));
            String readLine = null;
            StringBuffer response = new StringBuffer();
            while (null != (readLine = bufferedReader.readLine())) {
                response.append(readLine);
            }

            bufferedReader.close();
            responseBody = response.toString();
        }
    } catch (IOException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }

    return responseBody;
}

其中传入的参数String url是发送Get请求的URL，若发送带请求参数的Get请求，那么该url是已拼接好的带请求参数的字符串。

发送Post请求的方法如下:

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public static String sendPost(String url, String params) {
        String responseBody = null;
    try {
        URL postUrl = new URL(url);
        HttpURLConnection urlConnection = (HttpURLConnection)postUrl
                    .openConnection();
        urlConnection.setRequestMethod("POST");
        urlConnection.setRequestProperty("Content-Type",
                    "application/x-www-form-urlencoded;charset=utf-8");
        urlConnection.setRequestProperty("Content-Length",
                    String.valueOf(params.length()));
        urlConnection.setDoOutput(true);
        urlConnection.setUseCaches(false);
        urlConnection.setConnectTimeout(30000);
        urlConnection.setReadTimeout(30000);
        urlConnection.connect();

        DataOutputStream outputStream = new DataOutputStream(
                    urlConnection.getOutputStream());
        outputStream.writeBytes(params);
        outputStream.flush();
        outputStream.close();

        int respCode = urlConnection.getResponseCode();
        if (HttpURLConnection.HTTP_OK == respCode) {
                BufferedReader bufferedReader = new BufferedReader(
                        new InputStreamReader(urlConnection.getInputStream(),
                                "UTF-8"));
            String inputLine = null;
            StringBuffer response = new StringBuffer();
            while (null != (inputLine = bufferedReader.readLine())) {
                response.append(inputLine);
            }

            bufferedReader.close();
            responseBody = response.toString();
        } else {
            //TODO:
        }

    } catch (IOException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }

    return responseBody;
}

可使用如下的方式调用上面的sendGet和sendPost方法:

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public static void main(String[] agrs) {
    String urlString = "http://localhost:8080/HttpRequestProcessor/weixin";
    try {
        String params = URLEncoder.encode("vobser", "UTF-8");
        String getURL = urlString + "?action=sendGet&params="+params;
        String response = HttpRequest.sendGet(getURL);
        System.out.println("get response = " + response);
            
        String postUrl = urlString;
        StringBuffer paramsBuffer = new StringBuffer();
        paramsBuffer.append("action=");
        //使用URLEncoder.encode对特殊和不可见字符进行编码
        paramsBuffer.append(URLEncoder.encode("get info", "UTF-8"));
        paramsBuffer.append("&param=");
        paramsBuffer.append(URLEncoder.encode("云竹", "UTF-8"));
        response = HttpRequest.sendPost(postUrl, paramsBuffer.toString());
        System.out.println("post response = " + response);
    } catch (UnsupportedEncodingException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
        
}