Java使用HttpURLConnection发送POST和GET请求

代码示例

/**
* http 请求工具类
* Created by zhh on 2017/12/08.
*/
public class HttpHelper {

// 每次读取大小
private final static int READ_BODY_SIZE = 5120;

/**
* post 方式请求内容
* @param strUrl url地址
* @param paramMap 参数集
* @return
*/
public static String post(String strUrl, Map<String, Object> paramMap) {
StringBuffer sb = new StringBuffer();
for (String strKey : paramMap.keySet()) {
sb.append("&");
sb.append(strKey);
sb.append("=");
sb.append(paramMap.get(strKey));
}
sb.replace(0, 1, "?");
if (sb.length() > 0) {
return post(strUrl + sb.toString(), "");
}
return post(strUrl + sb.toString(), "");
}

/**
* get 方式请求内容
* @param strUrl url地址
* @param paramMap 参数集
* @return
*/
public static String get(String strUrl, Map<String, Object> paramMap) {
StringBuffer sb = new StringBuffer();
for (String strKey : paramMap.keySet()) {
sb.append("&");
sb.append(strKey);
sb.append("=");
sb.append(paramMap.get(strKey));
}
sb.replace(0, 1, "?");
if (sb.length() > 0) {
return get(strUrl + sb.toString());
}
return get(strUrl + sb.toString());
}

/**
* post 方式请求内容
* @param strUrl url地址
* @param content 输出内容
* @return
*/
public static String post(String strUrl, String content) {
return post(strUrl, content, 180);
}

/**
* get 方式请求内容
* @param strUrl url地址
* @return
*/
public static String get(String strUrl) {
return get(strUrl, 180);
}

/**
* post 方式请求内容
* @param strUrl url地址
* @param content 输出内容
* @param timeoutSecond 设置延时时间
* @return
*/
public static String post(String strUrl, String content, int timeoutSecond) {
try {
URL url = new URL(strUrl);
HttpURLConnection con = (HttpURLConnection) url.openConnection();
// 连接主机超时 毫秒
con.setConnectTimeout(timeoutSecond * 1000);
// 从主机读取数据超时毫秒
con.setReadTimeout(timeoutSecond * 1000);
// 设置从HttpURLConnection读入
con.setDoInput(true);
// 设置是否向httpUrlConnection输出, 因为这个是post请求, 参数要放在http正文内, 因此需要设为true, 默认情况下是false
con.setDoOutput(true);
// 设置该URLConnection的allowUserInteraction请求头字段的值
con.setAllowUserInteraction(false);
con.setUseCaches(true);
con.setRequestMethod("POST");
con.setRequestProperty("Content-Type", "application/x-www-form-urlencoded;charset=UTF-8");
// 此处getOutputStream会隐含的进行connect,所以在开发中不调用上述的connect()也可以
BufferedWriter bout = new BufferedWriter(new OutputStreamWriter(con.getOutputStream()));
bout.write(content);
bout.flush();
bout.close();
return streamReadHtml(con.getInputStream());
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
return null;
}

/**
* get 方式请求内容
* @param strUrl url地址
* @param timeoutSecond 设置延时时间
* @return
*/
public static String get(String strUrl, int timeoutSecond) {
try {
URL url = new URL(strUrl);
HttpURLConnection con = (HttpURLConnection) url.openConnection();
// 连接主机超时 毫秒
con.setConnectTimeout(timeoutSecond * 1000);
// 从主机读取数据超时毫秒
con.setReadTimeout(timeoutSecond * 1000);
con.setRequestMethod("GET");
con.setRequestProperty("Content-Type", "application/x-www-form-urlencoded;charset=UTF-8");
con.connect();
return streamReadHtml(con.getInputStream());
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
return null;
}

/**
* 读取内容
* @param istream
* @return
* @throws UnsupportedEncodingException
*/
public static String streamReadHtml(InputStream istream) throws UnsupportedEncodingException {
String html = "";
byte[] responseBody = new byte[READ_BODY_SIZE];
int npos = 0;
int nread = 0;
try {
while ((nread = istream.read(responseBody, npos, responseBody.length - npos)) >= 0) {
npos += nread;
byte[] tmpBuf = new byte[npos + READ_BODY_SIZE];
System.arraycopy(responseBody, 0, tmpBuf, 0, npos);
responseBody = tmpBuf;
}
} catch (IOException e) {
e.printStackTrace();
} finally {
try {
if (istream != null) {
istream.close();
}
istream = null;
} catch (Exception e) {
e.printStackTrace();
}
}
html = new String(responseBody, 0, npos, "UTF-8");
return html;
}

}

测试用例

public static void main(String[] args) {
String reqUrl = "https://www.baidu.com";
Map<String, Object> paramMap = new HashMap<>();
paramMap.put("wd", "测试");
System.out.println(HttpHelper.post(reqUrl, paramMap));
}