HttpClient 是apache 组织下面的一个用于处理HTTP 请求和响应的开源工具。所用jar包为httpclient-4.3.6.jar、httpcore-4.3.3.jar、httpmime-4.3.6.jar、commons-codec-1.6.jar。

发送Get请求代码如下：

package com.zkn.newlearn.httpclient;

import java.io.BufferedReader;

import java.io.IOException;

import java.io.InputStream;

import java.io.InputStreamReader;

import java.util.List;

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.impl.client.CloseableHttpClient;

import org.apache.http.impl.client.HttpClients;

import org.apache.http.message.BasicNameValuePair;

import org.apache.http.util.EntityUtils;

import com.google.common.collect.Lists;

public class HttpClientTest02 {

public static void main(String[] args) {

CloseableHttpClient httpClient = HttpClients.createDefault();

CloseableHttpResponse response = null;

InputStream is = null;

String url = "http://localhost:8080/MyWebxTest/getCityByProvinceEname.do";

//封装请求参数

List params = Lists.newArrayList();

params.add(new BasicNameValuePair("cityEname", "henan"));

String str = "";

try {

//转换为键值对

str = EntityUtils.toString(new UrlEncodedFormEntity(params, Consts.UTF_8));

System.out.println(str);

//创建Get请求

HttpGet httpGet = new HttpGet(url+"?"+str);

//执行Get请求，

response = httpClient.execute(httpGet);

//得到响应体

HttpEntity entity = response.getEntity();

if(entity != null){

is = entity.getContent();

//转换为字节输入流

BufferedReader br = new BufferedReader(new InputStreamReader(is, Consts.UTF_8));

String body = null;

while((body=br.readLine()) != null){

System.out.println(body);

}

}

} catch (ParseException e) {

e.printStackTrace();

} catch (IOException e) {

e.printStackTrace();

} finally{

//关闭输入流，释放资源

if(is != null){

try {

is.close();

} catch (IOException e) {

e.printStackTrace();

}

}

//消耗实体内容

if(response != null){

try {

response.close();

} catch (IOException e) {

e.printStackTrace();

}

}

//关闭相应 丢弃http连接

if(httpClient != null){

try {

httpClient.close();

} catch (IOException e) {

e.printStackTrace();

}

}

}

}

}