java——HttpClient的GET以及POST请求实例工具

HTTP简单介绍：

HTTP 协议可能是现在 Internet 上使用得最多、最重要的协议了，越来越多的 Java 应用程序需要直接通过 HTTP 协议来访问网络资源。虽然在 JDK 的 java.net 包中已经提供了访问 HTTP 协议的基本功能，但是对于大部分应用程序来说，JDK 库本身提供的功能还不够丰富和灵活。HttpClient 是 Apache Jakarta Common 下的子项目，用来提供高效的、最新的、功能丰富的支持 HTTP 协议的客户端编程工具包，并且它支持 HTTP 协议最新的版本和建议。

import org.apache.http.NameValuePair;
import org.apache.http.client.entity.UrlEncodedFormEntity;
import org.apache.http.client.methods.CloseableHttpResponse;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.client.utils.URIBuilder;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.message.BasicNameValuePair;
import org.apache.http.util.EntityUtils;
import org.springframework.util.StringUtils;

import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;

/**
 * @Author ：feiyang
 * @Date ：Created in 2019/5/15
 */
public class HttpClientUtil {

    private static CloseableHttpClient httpClient = HttpClients.createDefault();

    /**
     * POST 有参
     * @param host
     * @param port
     * @param uri
     * @param paramsMap
     * @return
     */
    public static String sendPost(String host, String port, String uri, Map<String, Object> paramsMap){
        try {
            String url = "http://"+host+":"+port+"/"+uri;
            HttpPost post = new HttpPost(url);
            if (!StringUtils.isEmpty(paramsMap)){
                List<NameValuePair> params = new ArrayList<>();
                for (Map.Entry<String, Object> entry : paramsMap.entrySet()
                ) {
                    params.add(new BasicNameValuePair(entry.getKey(), entry.getValue().toString()));
                }
                UrlEncodedFormEntity formEntity = new UrlEncodedFormEntity(params, "UTF-8");
                post.setEntity(formEntity);
            }
            CloseableHttpResponse  response = httpClient.execute(post);
            if (!StringUtils.isEmpty(response.getEntity())){
                return EntityUtils.toString(response.getEntity(), "UTF-8");
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
        return null;
    }

    /**
     * POST 无参
     * @param host
     * @param port
     * @param uri
     * @return
     */
    public static String sendPost(String host, String port, String uri){
        try {
            String url = "http://"+host+":"+port+"/"+uri;
            HttpPost post = new HttpPost(url);
            CloseableHttpResponse response = httpClient.execute(post);
            if (!StringUtils.isEmpty(response.getEntity())){
                return EntityUtils.toString(response.getEntity(), "UTF-8");
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
        return null;
    }

    /**
     * GET 有参
     * @param host
     * @param port
     * @param uri
     * @param paramsMap
     * @return
     */
    public static String sendGet(String host, String port, String uri, Map<String, Object> paramsMap){
        try {
            String url = "http://"+host+":"+port+"/"+uri;
            URIBuilder uriBuilder = new URIBuilder(url);
            if (paramsMap != null) {
                for (Map.Entry<String, Object> entry : paramsMap.entrySet()) {
                    uriBuilder.setParameter(entry.getKey(), entry.getValue().toString());
                }
            }
            HttpGet httpGet = new HttpGet(uriBuilder.build());
            CloseableHttpResponse response = httpClient.execute(httpGet);
            if (response.getEntity() != null) {
                return EntityUtils.toString(response.getEntity(), "UTF-8");
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
        return null;
    }

    /**
     * GET 无参
     * @param host
     * @param port
     * @param uri
     * @return
     */
    public static String sendGet(String host, String port, String uri){
        try {
            String url = "http://"+host+":"+port+"/"+uri;
            HttpGet httpGet = new HttpGet(url);
            CloseableHttpResponse response = httpClient.execute(httpGet);
            if (response.getEntity() != null) {
                return EntityUtils.toString(response.getEntity(), "UTF-8");
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
        return null;
    }

}