http get请求

import java.io.IOException;
import java.net.URI;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;

import org.apache.commons.lang3.StringUtils;
import org.apache.http.HttpEntity;
import org.apache.http.HttpStatus;
import org.apache.http.client.config.RequestConfig;
import org.apache.http.client.methods.CloseableHttpResponse;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.util.EntityUtils;

/**
*
* GET接口服务的JAVA示例
*
*/
public class HttpGetApiInvoker {

private final static String URL = "http://test/url";

private final static String REQUEST_CHARSET     =   "UTF-8";
private final static String RESPONSE_CHARSET    =   "UTF-8";
private final static int    CONNECT_TIMEOUT     =   5000;               //调用连接超时时间
private final static int    REQUEST_TIMEOUT     =   10000;              //调用获取数据超时时间

public static void main(String[] args) throws Exception{
HttpGetApiInvoker httpGetApiInvoker= new HttpGetApiInvoker();
Map<String, Object> parameterList = httpGetApiInvoker.prepareParameter();
String result = httpGetApiInvoker.invoke(parameterList);
System.out.println(result);
}

/***
* 准备业务参数
* @return
*/
private Map<String, Object> prepareParameter(){
Map<String, Object> parameterMap = new HashMap<>();
parameterMap.put("name", "xxx");
parameterMap.put("password", "xxxxxxxx");
return parameterMap;
}

/***
* 拼接调用的URL
* @param url
* @param parametersMap 业务数据，作为参数
* @return
*/
private URI buildUri(String url, Map<String, Object> parametersMap) {
if (null == parametersMap || parametersMap.isEmpty()) {
return URI.create(url);
}
ArrayList list = new ArrayList(parametersMap.size());
Iterator iterator = parametersMap.entrySet().iterator();

while (iterator.hasNext()) {
Map.Entry entry = (Map.Entry) iterator.next();
list.add(entry.getKey().toString().trim() + "=" + entry.getValue().toString().trim());
}
return list.isEmpty() ? URI.create(url) : URI.create(url + "?" + StringUtils.join(list, "&"));
}

/***
* 没有使用长连接
* @param parameterMap
* @return  JSON格式的字符串
* @throws IOException
*/
private String invoke(Map<String, Object> parameterMap) throws IOException {
HttpGet httpGet = null;
String result = "";
try {

//拼接URL
httpGet = new HttpGet(buildUri(URL,parameterMap));

//设置超时时间
RequestConfig requestConfig = RequestConfig.custom()
.setConnectTimeout(CONNECT_TIMEOUT)
.setSocketTimeout(REQUEST_TIMEOUT)
.build();
httpGet.setConfig(requestConfig);

httpGet.addHeader("Content-Type", "application/x-www-form-urlencoded; charset=" + REQUEST_CHARSET);

CloseableHttpClient httpClient = HttpClients.createDefault();

CloseableHttpResponse httpResponse = httpClient.execute(httpGet);
HttpEntity httpEntity = httpResponse.getEntity();

//返回值不是200，进行错误处理
if(HttpStatus.SC_OK != httpResponse.getStatusLine().getStatusCode()){

//相关处理
if(null != httpGet) {
httpGet.abort();
}
return result;
}

//获取结果
result = EntityUtils.toString(httpEntity, RESPONSE_CHARSET);

}catch(Exception e){
if(null != httpGet){
httpGet.abort();
}
throw e;
}
return result;
}
}

<dependency>
<groupId>org.apache.commons</groupId>
<artifactId>commons-lang3</artifactId>
<version>3.3.2 </version>
</dependency>

<dependency>
<groupId>org.apache.httpcomponents</groupId>
<artifactId>httpclient</artifactId>
<version> 4.3.6</version>
</dependency>

<dependency>
<groupId>org.apache.httpcomponents</groupId>
<artifactId>httpcore</artifactId>
<version>4.4</version>
</dependency>