Java工具类--通过HttpClient发送http请求

http://blog.csdn.net/frankcheng5143/article/details/50070591

用到的jar包有httpclient-4.5.1.jar，httpcore-4.4.3.jar，注意是Apache HttpClient，不是commons-httpclient

import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import org.apache.http.Consts;
import org.apache.http.HttpEntity;
import org.apache.http.NameValuePair;
import org.apache.http.ParseException;
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.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.message.BasicNameValuePair;
import org.apache.http.util.EntityUtils;
/**
 * @author GWCheng
 *
 */
public class HttpUtil {

    private static final CloseableHttpClient httpclient = HttpClients.createDefault();

    /**
     * 发送HttpGet请求
     * @param url
     * @return
     */
    public static String sendGet(String url) {

        HttpGet httpget = new HttpGet(url);
        CloseableHttpResponse response = null;
        try {
            response = httpclient.execute(httpget);
        } catch (IOException e1) {
            e1.printStackTrace();
        }
        String result = null;
        try {
            HttpEntity entity = response.getEntity();
            if (entity != null) {
                result = EntityUtils.toString(entity);
            }
        } catch (ParseException | IOException e) {
            e.printStackTrace();
        } finally {
            try {
                response.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        return result;
    }

    /**
     * 发送HttpPost请求，参数为map
     * @param url
     * @param map
     * @return
     */
    public static String sendPost(String url, Map map) {
        List formparams = new ArrayList();
        for (Map.Entry entry : map.entrySet()) {
            formparams.add(new BasicNameValuePair(entry.getKey(), entry.getValue()));
        }
        UrlEncodedFormEntity entity = new UrlEncodedFormEntity(formparams, Consts.UTF_8);
        HttpPost httppost = new HttpPost(url);
        httppost.setEntity(entity);
        CloseableHttpResponse response = null;
        try {
            response = httpclient.execute(httppost);
        } catch (IOException e) {
            e.printStackTrace();
        }
        HttpEntity entity1 = response.getEntity();
        String result = null;
        try {
            result = EntityUtils.toString(entity1);
        } catch (ParseException | IOException e) {
            e.printStackTrace();
        }
        return result;
    }

    /**
     * 发送不带参数的HttpPost请求
     * @param url
     * @return
     */
    public static String sendPost(String url) {
        HttpPost httppost = new HttpPost(url);
        CloseableHttpResponse response = null;
        try {
            response = httpclient.execute(httppost);
        } catch (IOException e) {
            e.printStackTrace();
        }
        HttpEntity entity = response.getEntity();
        String result = null;
        try {
            result = EntityUtils.toString(entity);
        } catch (ParseException | IOException e) {
            e.printStackTrace();
        }
        return result;
    }

}

往body体中放数据

StringEntity entity = new StringEntity(entityInput);
httppost.setEntity(entity);

FileEntity entity = new FileEntity(new File(""));
httppost.setEntity(entity);