之前写过一个Java工具类–通过HttpClient发送http请求

最近在访问一个接口的时候被拒绝了。具体信息如下

我们用程序访问我的csdn博客地址

解决方案就是在httpclient发出请求的时候在Header中设置一个User-Agent

HTTP响应头和请求头信息对照表

具体如下

    String userAgent = "Mozilla/5.0 (Windows NT 6.2; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/54.0.2840.87 Safari/537.36";
    HttpGet httpGet = new HttpGet(url);
    httpGet.setHeader("User-Agent",userAgent);
    response = httpclient.execute(httpGet);

我电脑的谷歌浏览器User-Agent

加上User-Agent之后访问我的博客地址

完整的代码

HttpUtil.java

package com.jrbac.util;

import java.io.File;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;

import org.apache.http.Consts;
import org.apache.http.HttpEntity;
import org.apache.http.NameValuePair;
import org.apache.http.client.ClientProtocolException;
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.entity.StringEntity;
import org.apache.http.entity.mime.HttpMultipartMode;
import org.apache.http.entity.mime.MultipartEntityBuilder;
import org.apache.http.entity.mime.content.FileBody;
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 org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * Http工具类，发送Http请求， Get请求请将参数放在url中 Post请求请将参数放在Map中
 * 
 * @author 程高伟
 * @date 2017年1月5日 下午6:03:50
 */
public class HttpUtil {
    private static final Logger log = LoggerFactory.getLogger(HttpUtil.class);
    private static final CloseableHttpClient httpclient = HttpClients.createDefault();
    private static final String userAgent = "Mozilla/5.0 (Windows NT 6.2; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/54.0.2840.87 Safari/537.36";

    /**
 * 发送HttpGet请求
 * 
 * @param url
 * 请求地址
 * @return 返回字符串
 */
    public static String sendGet(String url) {
        String result = null;
        CloseableHttpResponse respOnse= null;
        try {
            HttpGet httpGet = new HttpGet(url);
            httpGet.setHeader("User-Agent", userAgent);
            respOnse= httpclient.execute(httpGet);
            HttpEntity entity = response.getEntity();
            if (entity != null) {
                result = EntityUtils.toString(entity);
            }
        } catch (Exception e) {
            log.error("处理失败 {}" + e);
            e.printStackTrace();
        } finally {
            if (response != null) {
                try {
                    response.close();
                } catch (IOException e) {
                    log.error(e.getMessage());
                }
            }
        }
        return result;
    }

    /**
 * 发送HttpPost请求，参数为map
 * 
 * @param url
 * 请求地址
 * @param map
 * 请求参数
 * @return 返回字符串
 */
    public static String sendPost(String url, Map map) {
        // 设置参数
        List formparams = new ArrayList();
        for (Map.Entry entry : map.entrySet()) {
            formparams.add(new BasicNameValuePair(entry.getKey(), entry.getValue()));
        }
        // 编码
        UrlEncodedFormEntity formEntity = new UrlEncodedFormEntity(formparams, Consts.UTF_8);
        // 取得HttpPost对象
        HttpPost httpPost = new HttpPost(url);
        // 防止被当成攻击添加的
        httpPost.setHeader("User-Agent", userAgent);
        // 参数放入Entity
        httpPost.setEntity(formEntity);
        CloseableHttpResponse respOnse= null;
        String result = null;
        try {
            // 执行post请求
            respOnse= httpclient.execute(httpPost);
            // 得到entity
            HttpEntity entity = response.getEntity();
            // 得到字符串
            result = EntityUtils.toString(entity);
        } catch (IOException e) {
            log.error(e.getMessage());
        } finally {
            if (response != null) {
                try {
                    response.close();
                } catch (IOException e) {
                    log.error(e.getMessage());
                }
            }
        }
        return result;
    }

    /**
 * 发送HttpPost请求，参数为文件，适用于微信上传素材
 * 
 * @param url
 * 请求地址
 * @param file
 * 上传的文件
 * @return 返回字符串
 * @throws IOException
 * @throws ClientProtocolException
 */
    public static String sendPost(String url, File file) {
        String result = null;
        HttpPost httpPost = new HttpPost(url);
        // 防止被当成攻击添加的
        httpPost.setHeader("User-Agent", userAgent);
        MultipartEntityBuilder multipartEntity = MultipartEntityBuilder.create();
        multipartEntity.setMode(HttpMultipartMode.BROWSER_COMPATIBLE);
        multipartEntity.addPart("media", new FileBody(file));
        httpPost.setEntity(multipartEntity.build());
        CloseableHttpResponse respOnse= null;
        try {
            respOnse= httpclient.execute(httpPost);
            HttpEntity entity = response.getEntity();
            result = EntityUtils.toString(entity);
        } catch (IOException e) {
            log.error(e.getMessage());
        } finally {
            // 关闭CloseableHttpResponse
            if (response != null) {
                try {
                    response.close();
                } catch (IOException e) {
                    log.error(e.getMessage());
                }
            }
        }
        return result;

    }

    /**
 * 发送HttpPost请求，参数为json字符串
 * 
 * @param url
 * @param jsonStr
 * @return
 */
    public static String sendPost(String url, String jsonStr) {
        String result = null;
        // 字符串编码
        StringEntity entity = new StringEntity(jsonStr, Consts.UTF_8);
        // 设置content-type
        entity.setContentType("application/json");
        HttpPost httpPost = new HttpPost(url);
        // 防止被当成攻击添加的
        httpPost.setHeader("User-Agent", userAgent);
        httpPost.setEntity(entity);
        CloseableHttpResponse respOnse= null;
        try {
            respOnse= httpclient.execute(httpPost);
            HttpEntity httpEntity = response.getEntity();
            result = EntityUtils.toString(httpEntity);
        } catch (IOException e) {
            log.error(e.getMessage());
        } finally {
            // 关闭CloseableHttpResponse
            if (response != null) {
                try {
                    response.close();
                } catch (IOException e) {
                    log.error(e.getMessage());
                }
            }
        }
        return result;
    }

    /**
 * 发送不带参数的HttpPost请求
 * 
 * @param url
 * @return
 */
    public static String sendPost(String url) {
        String result = null;
        // 得到一个HttpPost对象
        HttpPost httpPost = new HttpPost(url);
        // 防止被当成攻击添加的
        httpPost.setHeader("User-Agent", userAgent);
        CloseableHttpResponse respOnse= null;
        try {
            // 执行HttpPost请求，并得到一个CloseableHttpResponse
            respOnse= httpclient.execute(httpPost);
            // 从CloseableHttpResponse中拿到HttpEntity
            HttpEntity entity = response.getEntity();
            // 将HttpEntity转换为字符串
            result = EntityUtils.toString(entity);
        } catch (IOException e) {
            log.error(e.getMessage());
        } finally {
            // 关闭CloseableHttpResponse
            if (response != null) {
                try {
                    response.close();
                } catch (IOException e) {
                    log.error(e.getMessage());
                }
            }
        }
        return result;
    }
}

参考文献

HTTP响应头和请求头信息对照表