HttpClient javaweb后端请求方法封装

重要信息写在前面:

相关jar，已上传csdn。

注:编译通过只需要引入httpclient-4.5.6.jar、httpcore-4.4.10.jar两个包即可

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.URI;
import java.nio.charset.StandardCharsets;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;

import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.HttpStatus;
import org.apache.http.NameValuePair;
import org.apache.http.StatusLine;
import org.apache.http.client.HttpClient;
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.entity.StringEntity;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClientBuilder;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.message.BasicNameValuePair;
import org.apache.http.util.EntityUtils;

/**
 *@author 创建人：zxy
* @version 创建时间：2018年10月29日 上午10:51:10
* 类说明：java后台HTTP请求方法
 */
public class HttpUtil {

	/**get请求
	 * @param url
	 * @return
	 */
	public static String doGet(String url) {
		try {
			HttpClient client = HttpClientBuilder.create().build();
			// 发送get请求
			HttpGet request = new HttpGet(url);
			HttpResponse response = client.execute(request);
			// 请求发送成功，并得到响应
			if (response.getStatusLine().getStatusCode() == HttpStatus.SC_OK) {
				// 读取服务器返回过来的json字符串数据
				String strResult = EntityUtils.toString(response.getEntity());
				return strResult;
			}
		} catch (IOException e) {
			e.printStackTrace();
		}
		return null;
	}
	
	/**
	 * post请求(用于key-value格式的参数)
	 * @param url
	 * @param params
	 * @return
	 */
	public static String doPost(String url, Map<String, Object> params) {
		BufferedReader in = null;
		try {
			// 定义HttpClient
			HttpClient client = HttpClientBuilder.create().build();
			// 实例化HTTP方法
			HttpPost request = new HttpPost();
			request.setURI(new URI(url));
			// 设置参数
			List<NameValuePair> nvps = new ArrayList<NameValuePair>();
			for (Entry<String, Object> entry : params.entrySet()) {
				nvps.add(new BasicNameValuePair(entry.getKey(), entry.getValue() + ""));
			}
			request.setEntity(new UrlEncodedFormEntity(nvps, StandardCharsets.UTF_8));
			HttpResponse response = client.execute(request);
			int code = response.getStatusLine().getStatusCode();
			if (code == 200) { // 请求成功
				in = new BufferedReader(
						new InputStreamReader(response.getEntity().getContent(), StandardCharsets.UTF_8));
				StringBuffer sb = new StringBuffer("");
				String line = "";
				String NL = System.getProperty("line.separator");
				while ((line = in.readLine()) != null) {
					sb.append(line + NL);
				}
				in.close();
				return sb.toString();
			} else {
				System.out.println("状态码：" + code);
				return null;
			}
		} catch (Exception e) {
			e.printStackTrace();

			return null;
		}
	}
	
	/**
	 * post请求（用于请求json格式的参数）
	 * @param url
	 * @param params
	 * @return
	 */
	public static String doPost(String url, String params) throws Exception {
		CloseableHttpClient httpclient = HttpClients.createDefault();
		HttpPost httpPost = new HttpPost(url);// 创建httpPost
		httpPost.setHeader("Accept", "application/json");
		httpPost.setHeader("Content-Type", "application/json");
		String charSet = "UTF-8";
		StringEntity entity = new StringEntity(params, charSet);
		httpPost.setEntity(entity);
		CloseableHttpResponse response = null;
		try {
			response = httpclient.execute(httpPost);
			StatusLine status = response.getStatusLine();
			int state = status.getStatusCode();
			if (state == HttpStatus.SC_OK) {
				HttpEntity responseEntity = response.getEntity();
				String jsonString = EntityUtils.toString(responseEntity);
				return jsonString;
			} else {
				System.out.println("请求返回:" + state + "(" + url + ")");
			}
		} finally {
			if (response != null) {
				try {
					response.close();
				} catch (IOException e) {
					e.printStackTrace();
				}
			}
			try {
				httpclient.close();
			} catch (IOException e) {
				e.printStackTrace();
			}
		}
		return null;
	}
	
}