HttpClient技术

时间静止不是简史

发布于 2020-07-25 23:56:59

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发布于 2020-07-25 23:56:59

文章被收录于专栏：Java探索之路Java探索之路

HttpClient

一、介绍
- 简介
- 坐标
二、应用
- 发送get请求不带参数
- 发送get请求带参数
- 发送post请求不带参数
- 发送post请求带参数
- 发送post请求带json类型参数
三、HTTPClient工具类的使用
- 工具类代码

一、介绍

简介

HttpClient 是 Apache Jakarta Common 下的子项目，可以用来提供高效的、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。
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。

坐标

在创建Maven工程项目时,在pom.xml中添加如下坐标即可自动导入相关jar包

	<!-- https://mvnrepository.com/artifact/org.apache.httpcomponents/httpclient -->
		<dependency>
			<groupId>org.apache.httpcomponents</groupId>
			<artifactId>httpclient</artifactId>
			<version>4.3.5</version>
		</dependency>

二、应用

发送get请求不带参数

1、创建一个httpclient对象 2、创建Get请求对象,在请求中输入url 3、发送请求,并返回响应 4、处理响应, 获取响应的状态码 5、获取响应的内容 6、关闭连接

/**
	 * get请求不带参数
	 * @throws ClientProtocolException
	 * @throws IOException
	 */
	public static void doGet() throws ClientProtocolException, IOException {
		//创建一个httpclient对象
		CloseableHttpClient client = HttpClients.createDefault();
		//创建Get请求对象,在请求中输入url
		HttpGet Get = new HttpGet("http://www.baidu.com");
		//发送请求,并返回响应
		CloseableHttpResponse response = client.execute(Get);
		
		//处理相应
		//获取相应的状态码
		int statusCode = response.getStatusLine().getStatusCode();
		System.out.println(statusCode);
		
		//获取相应的内容
		HttpEntity entity = response.getEntity();
		String responseBody = EntityUtils.toString(entity, "utf-8");
		System.out.println(responseBody);
		//关闭连接
		client.close();
	}

发送get请求带参数

1、创建一个httpclient对象 2、封装一个uri对象,在该对象中可以指定参数 3、创建Get请求对象,在请求中输入url 3、发送请求,并返回响应 4、处理响应, 获取响应的状态码 5、获取响应的内容 6、关闭连接

/**
	 * get请求带参数
	 * 
	 */
	public static void deGetParam() throws URISyntaxException, ClientProtocolException, IOException {
		CloseableHttpClient client = HttpClients.createDefault();
		//封装一个uri对象,在该对象中可以指定参数
		URIBuilder uri = new URIBuilder("https://www.jianshu.com/search");
		uri.addParameter("q","西游记");
		//创建一个get请求对象
		HttpGet get = new HttpGet(uri.build());
		CloseableHttpResponse response = client.execute(get);
		
		int statusCode = response.getStatusLine().getStatusCode();
		System.out.println(statusCode);
		HttpEntity entity = response.getEntity();
		String string = EntityUtils.toString(entity, "utf-8");
		System.out.println(string);
		client.close();
	}

发送post请求不带参数

1、创建一个httpclient对象 2、创建 post 请求对象,在请求中输入url 3、发送请求,并返回响应 4、处理响应, 获取响应的状态码 5、获取响应的内容 6、关闭连接

	/**
	 * post请求不带参
	 */
	public static void doPost() throws Exception{
		//发送请求
		CloseableHttpClient client = HttpClients.createDefault();
		HttpPost post = new HttpPost("http://localhost:8080/test/post");
		CloseableHttpResponse response = client.execute(post);
		
		//处理响应
		int statusCode = response.getStatusLine().getStatusCode();
		System.out.println("状态码"+statusCode);
		HttpEntity entity = response.getEntity();
		String string = EntityUtils.toString(entity, "utf-8");
		System.out.println("网页内容"+string);
		client.close();
	}

发送post请求带参数

1、创建一个httpclient对象 2、创建 post 请求对象,在请求中输入url 3、给定参数，将参数转换成字符串，并在post 请求中绑定参数 3、发送请求,并返回响应 4、处理响应, 获取响应的状态码 5、获取响应的内容 6、关闭连接

	/**
	 * post请求带参数
	 */
	public static void doPostParam() throws Exception{
		//发送请求
		CloseableHttpClient client = HttpClients.createDefault();
		HttpPost post = new HttpPost("http://localhost:8080/test/post/param");
		
		//给定参数
		ArrayList<BasicNameValuePair> list = new ArrayList<BasicNameValuePair>();
		list.add(new BasicNameValuePair("name", "时间静止"));
		list.add(new BasicNameValuePair("pwd", "chy"));
		//将参转换成字符串
		StringEntity entity = new UrlEncodedFormEntity(list,"utf-8");
		//向请求中韩绑定参数
		post.setEntity(entity);	
		CloseableHttpResponse response = client.execute(post);
		
		//处理响应
		int statusCode = response.getStatusLine().getStatusCode();
		System.out.println("状态码"+statusCode);
		HttpEntity entit = response.getEntity();
		String string = EntityUtils.toString(entit, "utf-8");
		System.out.println("网页内容"+string);
		client.close();
		
	}

发送post请求带json类型参数

1、创建一个httpclient对象 2、创建 post 请求对象,在请求中输入url 3、创建一个json字符串,将其放入StringEntity中,指定类型,并在post 请求中绑定该字符串 4、发送请求,并返回响应 5、处理响应, 获取响应的状态码 6、获取响应的内容 7、关闭连接

/**
	 * post请求携带参数(json)
	 */
	public static void doPostParamJson() throws Exception{
		//发送请求
		CloseableHttpClient client = HttpClients.createDefault();
		HttpPost post = new HttpPost("http://localhost:8080/test/post/param/json");
		String json="{\"name\":\"时间静止\",\"pwd\":\"chy\"}";
		StringEntity sentity=new StringEntity(json, ContentType.APPLICATION_JSON);
		post.setEntity(sentity);
		CloseableHttpResponse response = client.execute(post);
		
		//处理响应
		int statusCode = response.getStatusLine().getStatusCode();
		System.out.println("状态码"+statusCode);
		HttpEntity entit = response.getEntity();
		String string = EntityUtils.toString(entit, "utf-8");
		System.out.println("网页内容"+string);
		client.close();
		
		
	}

三、HTTPClient工具类的使用

工具类代码

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

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.entity.ContentType;
import org.apache.http.entity.StringEntity;
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;

public class HttpClientUtil {

	public static String doGet(String url, Map<String, String> param) {

		// 创建Httpclient对象
		CloseableHttpClient httpclient = HttpClients.createDefault();

		String resultString = "";
		CloseableHttpResponse response = null;
		try {
			// 创建uri
			URIBuilder builder = new URIBuilder(url);
			if (param != null) {
				for (String key : param.keySet()) {
					builder.addParameter(key, param.get(key));
				}
			}
			URI uri = builder.build();

			// 创建http GET请求
			HttpGet httpGet = new HttpGet(uri);

			// 执行请求
			response = httpclient.execute(httpGet);
			// 判断返回状态是否为200
			if (response.getStatusLine().getStatusCode() == 200) {
				resultString = EntityUtils.toString(response.getEntity(), "UTF-8");
			}
		} catch (Exception e) {
			e.printStackTrace();
		} finally {
			try {
				if (response != null) {
					response.close();
				}
				httpclient.close();
			} catch (IOException e) {
				e.printStackTrace();
			}
		}
		return resultString;
	}

	public static String doGet(String url) {
		return doGet(url, null);
	}

	public static String doPost(String url, Map<String, String> param) {
		// 创建Httpclient对象
		CloseableHttpClient httpClient = HttpClients.createDefault();
		CloseableHttpResponse response = null;
		String resultString = "";
		try {
			// 创建Http Post请求
			HttpPost httpPost = new HttpPost(url);
			// 创建参数列表
			if (param != null) {
				List<NameValuePair> paramList = new ArrayList<>();
				for (String key : param.keySet()) {
					paramList.add(new BasicNameValuePair(key, param.get(key)));
				}
				// 模拟表单
				UrlEncodedFormEntity entity = new UrlEncodedFormEntity(paramList,"utf-8");
				httpPost.setEntity(entity);
			}
			// 执行http请求
			response = httpClient.execute(httpPost);
			resultString = EntityUtils.toString(response.getEntity(), "utf-8");
		} catch (Exception e) {
			e.printStackTrace();
		} finally {
			try {
				response.close();
			} catch (IOException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
		}

		return resultString;
	}

	public static String doPost(String url) {
		return doPost(url, null);
	}
	
	public static String doPostJson(String url, String json) {
		// 创建Httpclient对象
		CloseableHttpClient httpClient = HttpClients.createDefault();
		CloseableHttpResponse response = null;
		String resultString = "";
		try {
			// 创建Http Post请求
			HttpPost httpPost = new HttpPost(url);
			// 创建请求内容
			StringEntity entity = new StringEntity(json, ContentType.APPLICATION_JSON);
			httpPost.setEntity(entity);
			// 执行http请求
			response = httpClient.execute(httpPost);
			resultString = EntityUtils.toString(response.getEntity(), "utf-8");
		} catch (Exception e) {
			e.printStackTrace();
		} finally {
			try {
				response.close();
			} catch (IOException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
		}

		return resultString;
	}
}

使用工具类案例

使用的post请求携带参数

public static void TestHTTPClientUtil() {
		
		String url="http://localhost:8080/test/post/param";
		Map<String, String> param=new HashMap<String, String>();
		param.put("name", "阿加");
		param.put("pwd", "ues");
		String result = HttpClientUtil.doPost(url, param);
		System.out.println(result);
	}

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原始发表：2019-08-02 ，如有侵权请联系 cloudcommunity@tencent.com 删除

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