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Java模拟HTTP的Get和Post请求

HttpClientHttp通信GET请求POST请求POST JSON 
阅读更多
   一、使用URLConnection实现GET和POST请求

 

    实现代码：

package test.util;

import java.io.BufferedOutputStream;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.HttpURLConnection;
import java.net.URL;
import java.net.URLConnection;
import java.util.Map;
import java.util.Map.Entry;

/**
 * 
 * @author junhu
 *
 */
public class HttpUtil
{
    /**
     * 使用URLConnection实现GET请求
     * 
     * 1.实例化一个java.net.URL对象； 2.通过URL对象的openConnection()方法得到一个java.net.URLConnection;
     * 3.通过URLConnection对象的getInputStream()方法获得输入流； 4.读取输入流； 5.关闭资源；
     */
    public static void get(String urlStr) throws Exception
    {

        URL url = new URL(urlStr);
        URLConnection urlConnection = url.openConnection(); // 打开连接

        System.out.println(urlConnection.getURL().toString());

        BufferedReader br = new BufferedReader(new InputStreamReader(urlConnection.getInputStream(), "utf-8")); // 获取输入流
        String line = null;
        StringBuilder sb = new StringBuilder();
        while ((line = br.readLine()) != null)
        {
            sb.append(line + "\n");
        }
        br.close();
        System.out.println(sb.toString());
    }

    /**
     * 使用HttpURLConnection实现POST请求
     * 
     * 1.实例化一个java.net.URL对象； 2.通过URL对象的openConnection()方法得到一个java.net.URLConnection;
     * 3.通过URLConnection对象的getOutputStream()方法获得输出流； 4.向输出流中写数据； 5.关闭资源；
     */
    public static void post(String urlStr, Map<String, String> parameterMap) throws IOException
    {

        URL url = new URL(urlStr);
        HttpURLConnection httpURLConnection = (HttpURLConnection) url.openConnection();

        httpURLConnection.setDoInput(true);
        httpURLConnection.setDoOutput(true); // 设置该连接是可以输出的
        httpURLConnection.setRequestMethod("POST"); // 设置请求方式
        httpURLConnection.setRequestProperty("charset", "utf-8");

        System.out.println(httpURLConnection.getURL().toString());

        PrintWriter pw = new PrintWriter(new BufferedOutputStream(httpURLConnection.getOutputStream()));
        
        StringBuffer parameter = new StringBuffer();
        parameter.append("1=1");
        for (Entry<String, String> entry : parameterMap.entrySet())
        {
            parameter.append("&" + entry.getKey() + "=" + entry.getValue());
        }
        pw.write(parameter.toString());// 向连接中写数据（相当于发送数据给服务器）
        
        pw.flush();
        pw.close();

        System.out.println("parameter: " + parameter.toString());

        BufferedReader br = new BufferedReader(new InputStreamReader(httpURLConnection.getInputStream(), "utf-8"));
        String line = null;
        StringBuilder sb = new StringBuilder();
        while ((line = br.readLine()) != null)
        { // 读取数据
            sb.append(line + "\n");
        }
        br.close();
        System.out.println(sb.toString());
    }
}

    测试代码：

package test.http;

import java.util.ArrayList;
import java.util.List;

import org.apache.http.NameValuePair;
import org.apache.http.message.BasicNameValuePair;

import test.util.HttpClientUtil;

/**
 * http通信测试
 * 
 * @author junhu
 */
public class TestHttp
{
    public static void main(String[] args)
    {
        try
        {
            // --------------测试请求/test/index begin---------------------------
            // HttpUtil.get("http://localhost:8080/Java_http/test/index?name=zhangsan&age=22&sex=nan");

            // Map<String, String> parameterMap = new HashMap<String, String>();
            // parameterMap.put("name", "zhangsan");
            // parameterMap.put("age", "22");
            // parameterMap.put("sex", "nan");
            // HttpUtil.post("http://localhost:8080/Java_http/test/index", parameterMap);
            // --------------测试请求/test/index end---------------------------

            // --------------测试请求/test/index2 begin---------------------------
            // HttpUtil.get("http://localhost:8080/Java_http/test/index2?userName=zhangsan&userAge=22&userSex=nan");

            // Map<String, String> parameterMap = new HashMap<String, String>();
            // parameterMap.put("userName", "zhangsan");
            // parameterMap.put("userAge", "22");
            // parameterMap.put("userSex", "nan");
            // HttpUtil.post("http://localhost:8080/Java_http/test/index2", parameterMap);
            // --------------测试请求/test/index2 end---------------------------
        }
        catch (Exception e)
        {
            e.printStackTrace();
        }
    }
}
 二、使用 HttpClient实现GET和POST请求

 

    实现代码：

package test.util;

import java.util.List;

import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.NameValuePair;
import org.apache.http.client.HttpClient;
import org.apache.http.client.entity.UrlEncodedFormEntity;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.util.EntityUtils;

/**
 * 
 * @author junhu
 *
 */
public class HttpClientUtil
{
    /**
     * 使用httpclient进行http通信
     * 
     * Get请求
     */
    public static void httpclientGet(String urlStr) throws Exception
    {

        System.out.println(urlStr);

        // 创建HttpClient对象
        HttpClient client = HttpClients.createDefault();

        // 创建GET请求（在构造器中传入URL字符串即可）
        HttpGet get = new HttpGet(urlStr);

        // 调用HttpClient对象的execute方法获得响应
        HttpResponse response = client.execute(get);

        // 调用HttpResponse对象的getEntity方法得到响应实体
        HttpEntity httpEntity = response.getEntity();

        // 使用EntityUtils工具类得到响应的字符串表示
        String result = EntityUtils.toString(httpEntity, "utf-8");
        System.out.println(result);
    }

    /**
     * 使用httpclient进行http通信
     * 
     * Post请求
     */
    public static void httpclientPost(String urlStr, List<NameValuePair> parameters) throws Exception
    {

        System.out.println(urlStr);

        // 创建HttpClient对象
        HttpClient client = HttpClients.createDefault();

        // 创建POST请求
        HttpPost post = new HttpPost(urlStr);

        // 创建一个List容器，用于存放基本键值对（基本键值对即：参数名-参数值）--> parameters

        // 向POST请求中添加消息实体
        post.setEntity(new UrlEncodedFormEntity(parameters, "utf-8"));

        // 得到响应并转化成字符串
        HttpResponse response = client.execute(post);
        HttpEntity httpEntity = response.getEntity();
        String result = EntityUtils.toString(httpEntity, "utf-8");
        System.out.println(result);
    }
}

    测试代码：

package test.http;

import java.util.ArrayList;
import java.util.List;

import org.apache.http.NameValuePair;
import org.apache.http.message.BasicNameValuePair;

import test.util.HttpClientUtil;

/**
 * http通信测试
 * 
 * @author junhu
 */
public class TestHttp
{
    public static void main(String[] args)
    {
        try
        {
            // --------------测试请求/test/index begin---------------------------
            // HttpClientUtil
            // .httpclientGet("http://localhost:8080/Java_http/test/index?name=zhangsan&age=22&sex=nan");

            // List<NameValuePair> parameters = new ArrayList<NameValuePair>();
            // parameters.add(new BasicNameValuePair("name", "zhangsan"));
            // parameters.add(new BasicNameValuePair("age", "22"));
            // parameters.add(new BasicNameValuePair("sex", "nan"));
            // HttpClientUtil.httpclientPost("http://localhost:8080/Java_http/test/index", parameters);
            // --------------测试请求/test/index end---------------------------

            // --------------测试请求/test/index2 begin---------------------------
            // HttpClientUtil
            // .httpclientGet("http://localhost:8080/Java_http/test/index2?userName=zhangsan&userAge=22&userSex=nan");

            List<NameValuePair> parameters = new ArrayList<NameValuePair>();
            parameters.add(new BasicNameValuePair("userName", "zhangsan"));
            parameters.add(new BasicNameValuePair("userAge", "22"));
            parameters.add(new BasicNameValuePair("userSex", "nan"));
            HttpClientUtil.httpclientPost("http://localhost:8080/Java_http/test/index2", parameters);
            // --------------测试请求/test/index2 end---------------------------
        }
        catch (Exception e)
        {
            e.printStackTrace();
        }
    }
}
 三、模拟POST请求发送JSON参数

 

    实现测试代码：

package test.http;

import java.io.IOException;

import org.apache.http.HttpEntity;
import org.apache.http.client.methods.CloseableHttpResponse;
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.HttpClients;
import org.apache.http.util.EntityUtils;

public class TestHttpWithJSON
{

    public static void httpPostWithJSON(String url, String json)
    {
        // 创建默认的httpClient实例
        CloseableHttpClient httpclient = HttpClients.createDefault();
        try
        {
            // 创建httppost
            HttpPost httppost = new HttpPost(url);
            httppost.addHeader("Content-type", "application/json; charset=utf-8");
            System.out.println("executing request " + httppost.getURI());

            // 向POST请求中添加消息实体
            StringEntity se = new StringEntity(json, "UTF-8");
            httppost.setEntity(se);
            System.out.println("request parameters " + json);

            // 执行post请求
            CloseableHttpResponse response = httpclient.execute(httppost);
            try
            {
                // 获取响应实体
                HttpEntity entity = response.getEntity();
                // 打印响应状态
                System.out.println(response.getStatusLine());
                if (entity != null)
                {
                    // 打印响应内容
                    System.out.println("--------------------------------------");
                    System.out.println("Response content: " + EntityUtils.toString(entity, "UTF-8"));
                    System.out.println("--------------------------------------");
                }
            }
            finally
            {
                response.close();
            }
        }
        catch (Exception e)
        {
            System.out.println("executing httpPostWithJSON error: " + e.getMessage());
        }
        finally
        {
            // 关闭连接,释放资源
            try
            {
                httpclient.close();
            }
            catch (IOException e)
            {
                System.out.println("executing httpPostWithJSON error: " + e.getMessage());
            }
        }
    }

    public static void main(String[] args)
    {
        // JsonObject jsonObject = new JsonObject();
        // jsonObject.addProperty("userName", "张三");
        // jsonObject.addProperty("userAge", "22");
        // jsonObject.addProperty("userSex", "男");
        // String url = "http://localhost:8080/Java_http/test/index3";
        // httpPostWithJSON(url, jsonObject.toString());

        String url = "http://localhost:8080/Java_http/test/index3";
        String json = "{\"userName\":\"张三\",\"userAge\":\"22\",\"userSex\":\"男\"}";
        httpPostWithJSON(url, json);
    }
}
 四、以下是公共的处理请求的代码（控制器） 
package test.controller;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.ModelAttribute;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.ResponseBody;

import test.bean.User;

/**
 * @author junhu
 */
@Controller
@RequestMapping("/test")
public class TestController {

    @RequestMapping(value = "/index", method = RequestMethod.GET)
    public String testGet(HttpServletRequest request, HttpServletResponse response)
    {
        System.out.println(request.getParameter("name"));
        System.out.println(request.getParameter("age"));
        System.out.println(request.getParameter("sex"));
        return "success";
    }

    @RequestMapping(value = "/index", method = RequestMethod.POST)
    public String testPost(HttpServletRequest request, HttpServletResponse response)
    {
        System.out.println(request.getParameter("name"));
        System.out.println(request.getParameter("age"));
        System.out.println(request.getParameter("sex"));
        return "success";
    }

    @RequestMapping(value = "/index2", method = RequestMethod.GET)
    public String testGetByObject(@ModelAttribute("user") User user, Model model)
    {
        System.out.println(user.getUserName());
        System.out.println(user.getUserAge());
        System.out.println(user.getUserSex());
		return "success";
	}

    @RequestMapping(value = "/index2", method = RequestMethod.POST)
    public String testPostByObject(@ModelAttribute("user") User user, Model model)
    {
        System.out.println(user.getUserName());
        System.out.println(user.getUserAge());
        System.out.println(user.getUserSex());
        return "success";
    }

    @RequestMapping(value = "/index3", method = RequestMethod.POST)
    public @ResponseBody User testPostByJson(@RequestBody User user, Model model)
    {
        System.out.println(user.getUserName());
        System.out.println(user.getUserAge());
        System.out.println(user.getUserSex());
        return user;
    }
}
   

   转载请注明出处：http://xieke90.iteye.com/blog/2259953

 
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