【commons-httpclient】Java中HttpClient工具访问Web请求

　　注意jar包是:

HttpClient工具使用

　　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。

　　为什么要使用HttpClient工具：

原生态的Socket基于传输层,现在我们要访问的WebService是基于HTTP的属于应用层,所以我们的Socket通信要借助HttpClient发HTTP请求,这样格式才能匹配

HttpClient使用步骤如下：

创建 HttpClient 的实例
创建某种连接方法的实例，在这里是 GetMethod。在 GetMethod 的构造函数中传入待连接的地址
配置要传输的参数，和消息头信息
调用第一步中创建好的实例的 execute 方法来执行第二步中创建好的 method 实例
通过response读取字符串
释放连接。无论执行方法是否成功，都必须释放连接

jar包:

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1。第一种使用方式:

Get方式：

public static void getMethod() throws Exception {

        // 创建get对象,类似get请求

        GetMethod getMethod = new GetMethod(        "http://webservice.webxml.com.cn/WebServices/MobileCodeWS.asmx/getMobileCodeInfo?mobileCode=18373551982&userID=");

        // 发送get请求

        int code = http.executeMethod(getMethod);

        System.out.println("返回的消息码为:" + code);

        System.out.println("返回的消息为:" + getMethod.getResponseBodyAsString());

        getMethod.releaseConnection();

    }

POST方式：

public static void postMethod() throws Exception {

        // 创建post请求,类似Post请求

        PostMethod postMethod = new PostMethod( "http://webservice.webxml.com.cn/WebServices/MobileCodeWS.asmx/getMobileCodeInfo");

        // 设置请求的正文内容

        postMethod.setRequestBody("mobileCode=18373551982&userID=");

        // 设置传送信息的格式

        postMethod.setRequestHeader("Content-Type",

                "application/x-www-form-urlencoded");

        // 发送post请求

        int code = http.executeMethod(postMethod);

        System.out.println("返回消息码为:" + code);

        System.out.println("返回的消息为:" + postMethod.getResponseBodyAsString());

        postMethod.releaseConnection();

    }

2.第二种使用方式

/**HttpClient访问网络的实现步骤：
       * 1. 准备一个请求客户端:浏览器
       * 2. 准备请求方式： GET 、POST
       * 3. 设置要传递的参数
       * 4.执行请求
       * 5. 获取结果
       */

get方式:(不用设置参数)

package ws_a;

import java.io.IOException;

import org.apache.commons.httpclient.HttpClient;

import org.apache.commons.httpclient.HttpException;

import org.apache.commons.httpclient.methods.GetMethod;

import org.junit.Test;

public class HttpClientTest {

    @Test

    public void testGet() throws HttpException, Exception{

        HttpClient client = new HttpClient();

        GetMethod getMethod = new GetMethod("http://ws.webxml.com.cn/WebServices/MobileCodeWS.asmx/getMobileCodeInfo?mobileCode="+"13110410513"+

                "&userID="+"");

        //4.执行请求 ,结果码

        int code=client.executeMethod(getMethod);

        //5. 获取结果

        String result=getMethod.getResponseBodyAsString();

        System.out.println("get请求的结果："+result);

    }

}

get请求的结果：<?xml version="1.0" encoding="utf-8"?>
<string xmlns="http://WebXml.com.cn/">13110410513：陕西西安陕西联通GSM卡</string>

Post方法:

    @Test

    public void post() throws Exception{

        HttpClient client=new HttpClient();

        PostMethod postMethod=new PostMethod("http://ws.webxml.com.cn/WebServices/MobileCodeWS.asmx/getMobileCodeInfo");

        //3.设置请求参数

        postMethod.setParameter("mobileCode", "13834786998");

        postMethod.setParameter("userID", "");

        //4.执行请求 ,结果码

        int code=client.executeMethod(postMethod);

        //5. 获取结果

        String result=postMethod.getResponseBodyAsString();

        System.out.println("Post请求的结果："+result);

    }

Post请求的结果：<?xml version="1.0" encoding="utf-8"?>
<string xmlns="http://WebXml.com.cn/">13834786998：山西长治山西移动全球通卡</string>

如果返回的中文乱码，我们可以设置编码:

        // 防止中文乱码

        postMethod.getParams().setContentCharset("utf-8");

maven地址:

        <!-- https://mvnrepository.com/artifact/commons-httpclient/commons-httpclient -->

        <dependency>

            <groupId>commons-httpclient</groupId>

            <artifactId>commons-httpclient</artifactId>

            <version>3.1</version>

        </dependency>