通过http rest请求返回数据

复制代码 代码如下:
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.http.NameValuePair;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.HttpClient;
import org.apache.http.client.ResponseHandler;
import org.apache.http.client.entity.UrlEncodedFormEntity;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.impl.client.BasicResponseHandler;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.impl.conn.tsccm.ThreadSafeClientConnManager;

import java.io.IOException;
import java.text.MessageFormat;
import java.util.List;
import java.util.concurrent.TimeUnit;

/**
* 分装一个http请求的工具类
*
* @author 顾炜【guwei】 on 14-4-22.下午3:17
*/
public class HttpClientUtils {

private static final Log log = LogFactory.getLog(HttpClientUtils.class);
/**
* 初始化HttpClient
*/
private static HttpClient httpClient = null;

/**
* 生产HttpClient实例
* 公开，静态的工厂方法，需要使用时才去创建该单体
*
* @return
*/
public static HttpClient getHttpClient() {
if (httpClient == null) {
httpClient = new DefaultHttpClient(new ThreadSafeClientConnManager());
}
return httpClient;
}

/**
* POST方式调用
*
* @param url
* @param params 参数为NameValuePair键值对对象
* @return 响应字符串
* @throws java.io.UnsupportedEncodingException
*/
public static String executeByPOST(String url, List<NameValuePair> params) {
HttpClient httpclient = getHttpClient();

HttpPost post = new HttpPost(url);

ResponseHandler<String> responseHandler = new BasicResponseHandler();
String responseJson = null;
try {
if (params != null) {
post.setEntity(new UrlEncodedFormEntity(params));
}
responseJson = httpclient.execute(post, responseHandler);
log.info("HttpClient POST请求结果：" + responseJson);
} catch (ClientProtocolException e) {
e.printStackTrace();
log.info("HttpClient POST请求异常：" + e.getMessage());
} catch (IOException e) {
e.printStackTrace();
} finally {
httpclient.getConnectionManager().closeExpiredConnections();
httpclient.getConnectionManager().closeIdleConnections(30, TimeUnit.SECONDS);
}
return responseJson;
}

/**
* Get方式请求
*
* @param url 带参数占位符的URL，例：http://****/User/user/center.aspx?_action=GetSimpleUserInfo&codes={0}&email={1}
* @param params 参数值数组，需要与url中占位符顺序对应
* @return 响应字符串
* @throws java.io.UnsupportedEncodingException
*/
public static String executeByGET(String url, Object[] params) {
HttpClient httpclient = getHttpClient();

String messages = MessageFormat.format(url, params);

HttpGet get = new HttpGet(messages);

ResponseHandler<String> responseHandler = new BasicResponseHandler();
String responseJson = null;
try {
responseJson = httpclient.execute(get, responseHandler);
log.info("HttpClient GET请求结果：" + responseJson);
} catch (ClientProtocolException e) {
e.printStackTrace();
log.info("HttpClient GET请求异常：" + e.getMessage());
} catch (IOException e) {
e.printStackTrace();
log.info("HttpClient GET请求异常：" + e.getMessage());
} finally {
httpclient.getConnectionManager().closeExpiredConnections();
httpclient.getConnectionManager().closeIdleConnections(30, TimeUnit.SECONDS);
}
return responseJson;
}

/**
* @param url
* @return
*/
public static String executeByGET(String url) {
HttpClient httpclient = getHttpClient();

HttpGet get = new HttpGet(url);

ResponseHandler<String> responseHandler = new BasicResponseHandler();
String responseJson = null;
try {
responseJson = httpclient.execute(get, responseHandler);
log.info("HttpClient GET请求结果：" + responseJson);
} catch (ClientProtocolException e) {
e.printStackTrace();
log.info("HttpClient GET请求异常：" + e.getMessage());
} catch (IOException e) {
e.printStackTrace();
log.info("HttpClient GET请求异常：" + e.getMessage());
} finally {
httpclient.getConnectionManager().closeExpiredConnections();
httpclient.getConnectionManager().closeIdleConnections(30, TimeUnit.SECONDS);
}
return responseJson;
}
}