Java发起Http请求

maven

<dependency>

            <groupId>org.apache.httpcomponents</groupId>

            <artifactId>httpcore</artifactId>

            <version>4.4.9</version>

        </dependency>

        <dependency>

            <groupId>org.apache.httpcomponents</groupId>

            <artifactId>httpclient</artifactId>

            <version>4.5.2</version>

        </dependency>

java代码

package com.fhlh.utils;

import org.apache.http.HttpEntity;

import org.apache.http.HttpResponse;

import org.apache.http.HttpStatus;

import org.apache.http.NameValuePair;

import org.apache.http.client.ClientProtocolException;

import org.apache.http.client.HttpClient;

import org.apache.http.client.ResponseHandler;

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.StringEntity;

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

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

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

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

import org.apache.http.message.BasicNameValuePair;

import org.apache.http.util.CharArrayBuffer;

import org.apache.http.util.EntityUtils;

import java.io.IOException;

import java.io.InputStream;

import java.io.InputStreamReader;

import java.io.UnsupportedEncodingException;

import java.net.URISyntaxException;

import java.util.ArrayList;

import java.util.List;

import java.util.Map;

/**

* 发送http请求工具类

*/

public class HttpUtils {

/**

    * http的post请求带有json的请求体

    * @param url

    * @param json

    * @return

    */

    public static StringHttpPostWithJson(String url, String json) {

long start = System.currentTimeMillis();

        String returnValue =”这是默认返回值，接口调用失败”;

        CloseableHttpClient httpClient = HttpClients.createDefault();

        ResponseHandler responseHandler =new BasicResponseHandler();

        try{

//第一步：创建HttpClient对象

            httpClient = HttpClients.createDefault();

            //第二步：创建httpPost对象

            HttpPost httpPost =new HttpPost(url);

            //第三步：给httpPost设置JSON格式的参数

            StringEntity requestEntity =new StringEntity(json,”utf-8″);

            requestEntity.setContentEncoding(“UTF-8”);

            httpPost.setHeader(“Content-type”, “application/json”);

            httpPost.setEntity(requestEntity);

            //第四步：发送HttpPost请求，获取返回值

            returnValue = httpClient.execute(httpPost,responseHandler); //调接口获取返回值时，必须用此方法

            httpClient.close();

        }

catch(Exception e)

{

e.printStackTrace();

        }finally {

try {

httpClient.close();

            }catch (IOException e) {

// TODO Auto-generated catch block

                e.printStackTrace();

            }

}

long end = System.currentTimeMillis();

        System.out.println(“time:”+(end-start));

        //第五步：处理返回值

        return returnValue;

    }

/**

    * http的post请求带有json的请求体

    * @param url

    * @param json

    * @return

    */

    public static StringHttpPostWithJsonAndHead(String url, String token, String json) {

long start = System.currentTimeMillis();

        String returnValue =”这是默认返回值，接口调用失败”;

        CloseableHttpClient httpClient = HttpClients.createDefault();

        ResponseHandler responseHandler =new BasicResponseHandler();

        try{

//第一步：创建HttpClient对象

            httpClient = HttpClients.createDefault();

            //第二步：创建httpPost对象

            HttpPost httpPost =new HttpPost(url);

            //第三步：给httpPost设置JSON格式的参数

            if(json !=null) {

StringEntity requestEntity =new StringEntity(json, “utf-8”);

                requestEntity.setContentEncoding(“UTF-8”);

                httpPost.setEntity(requestEntity);

            }

httpPost.setHeader(“Content-type”, “application/json”);

            httpPost.setHeader(“token”, token);

            //第四步：发送HttpPost请求，获取返回值

            returnValue = httpClient.execute(httpPost,responseHandler); //调接口获取返回值时，必须用此方法

            httpClient.close();

        }

catch(Exception e)

{

e.printStackTrace();

        }finally {

try {

httpClient.close();

            }catch (IOException e) {

// TODO Auto-generated catch block

                e.printStackTrace();

            }

}

long end = System.currentTimeMillis();

        System.out.println(“time:”+(end-start));

        //第五步：处理返回值

        return returnValue;

    }

/**

    * get请求，参数放在map里

    * @param url 请求地址

    * @param map 参数map

    * @return 响应

    */

    public StringgetMap(String url, Map map)

{

String result =null;

        CloseableHttpClient httpClient = HttpClients.createDefault();

        List pairs =new ArrayList();

      if(map !=null) {

for (Map.Entry entry : map.entrySet()) {

pairs.add(new BasicNameValuePair(entry.getKey(), entry.getValue()));

          }

}

CloseableHttpResponse response =null;

        try {

URIBuilder builder =new URIBuilder(url);

            builder.setParameters(pairs);

            HttpGet get =new HttpGet(builder.build());

            response = httpClient.execute(get);

            if(response !=null && response.getStatusLine().getStatusCode() ==200)

{

HttpEntity entity = response.getEntity();

                result =entityToString(entity);

            }

return result;

        }catch (URISyntaxException e) {

e.printStackTrace();

        }catch (ClientProtocolException e) {

e.printStackTrace();

        }catch (IOException e) {

e.printStackTrace();

        }finally {

try {

httpClient.close();

                if(response !=null)

{

response.close();

                }

}catch (IOException e) {

e.printStackTrace();

            }

}

return null;

    }

public static StringgetMapWithHeader(String url, String  token, Map map)

{

String result =null;

        CloseableHttpClient httpClient = HttpClients.createDefault();

        List pairs =new ArrayList();

        if(map !=null) {

for (Map.Entry entry : map.entrySet()) {

pairs.add(new BasicNameValuePair(entry.getKey(), entry.getValue()));

            }

}

CloseableHttpResponse response =null;

        try {

URIBuilder builder =new URIBuilder(url);

            builder.setParameters(pairs);

            HttpGet get =new HttpGet(builder.build());

            get.addHeader(“token”, token);

            response = httpClient.execute(get);

            if(response !=null && response.getStatusLine().getStatusCode() ==200)

{

HttpEntity entity = response.getEntity();

                result =entityToString(entity);

            }

return result;

        }catch (URISyntaxException e) {

e.printStackTrace();

        }catch (ClientProtocolException e) {

e.printStackTrace();

        }catch (IOException e) {

e.printStackTrace();

        }finally {

try {

httpClient.close();

                if(response !=null)

{

response.close();

                }

}catch (IOException e) {

e.printStackTrace();

            }

}

return null;

    }

private static  StringentityToString(HttpEntity entity)throws IOException {

String result =null;

        if(entity !=null)

{

long lenth = entity.getContentLength();

            if(lenth != -1 && lenth <2048)

{

result = EntityUtils.toString(entity,”UTF-8″);

            }else {

InputStreamReader reader1 =new InputStreamReader(entity.getContent(), “UTF-8”);

                CharArrayBuffer buffer =new CharArrayBuffer(2048);

                char[] tmp =new char[1024];

                int l;

                while((l = reader1.read(tmp)) != -1) {

buffer.append(tmp, 0, l);

                }

result = buffer.toString();

            }

}

return result;

    }

/**

    * 发送post请求，参数用map接收

    * @param url 地址

    * @param map 参数

    * @return 返回值

    */

    public StringpostMap(String url,Map map) {

String result =null;

        CloseableHttpClient httpClient = HttpClients.createDefault();

        HttpPost post =new HttpPost(url);

        List pairs =new ArrayList();

        for(Map.Entry entry : map.entrySet())

{

pairs.add(new BasicNameValuePair(entry.getKey(),entry.getValue()));

        }

CloseableHttpResponse response =null;

        try {

post.setEntity(new UrlEncodedFormEntity(pairs,”UTF-8″));

            response = httpClient.execute(post);

            if(response !=null && response.getStatusLine().getStatusCode() ==200)

{

HttpEntity entity = response.getEntity();

                result =entityToString(entity);

            }

return result;

        }catch (UnsupportedEncodingException e) {

e.printStackTrace();

        }catch (ClientProtocolException e) {

e.printStackTrace();

        }catch (IOException e) {

e.printStackTrace();

        }finally {

try {

httpClient.close();

                if(response !=null)

{

response.close();

                }

}catch (IOException e) {

e.printStackTrace();

            }

}

return null;

    }

public static StringhttpGet(String url)throws Exception{

String result=””; //返回信息

        //创建一个httpGet请求

        HttpGet request=new HttpGet(url);

        //创建一个htt客户端

        HttpClient httpClient=new DefaultHttpClient();

        //接受客户端发回的响应

        HttpResponse httpResponse=httpClient.execute(request);

        //获取返回状态

        int statusCode=httpResponse.getStatusLine().getStatusCode();

        if(statusCode== HttpStatus.SC_OK){

//得到客户段响应的实体内容

            HttpEntity responseHttpEntity=httpResponse.getEntity();

            //得到输入流

            InputStream in=responseHttpEntity.getContent();

            //得到输入流的内容

            result=getData(in);

        }

//Log.d(TAG, statusCode+””);

        return result;

    }

private static StringgetData(InputStream in)throws IOException {

StringBuffer sb =new StringBuffer();

        byte[] b =new byte[1024];

        int len = -1;

        while((len = in.read(b)) !=  -1){

sb.append(new String(b, 0, len));

        }

return sb.toString();

    }

public static void main(String[] args)throws Exception {

System.out.println(httpGet(“https://api.inews.qq.com/newsqa/v1/query/inner/publish/modules/list?modules=statisGradeCityDetail,diseaseh5Shelf”));

    }

}