Java HttpClient做http请求（form-data和json两种）

一、导入依赖

<dependency>
    <groupId>org.apache.httpcomponents</groupId>
    <artifactId>httpclient</artifactId>
    <version>4.5.13</version>
</dependency>
<dependency>
     <groupId>org.apache.httpcomponents</groupId>
     <artifactId>httpmime</artifactId>
     <version>4.5.13</version>
</dependency>

二、方法

package cn.com.wind.utils;

import cn.com.wind.exception.TranspondException;
import com.alibaba.fastjson.JSON;
import com.alibaba.fastjson.JSONObject;
import lombok.extern.slf4j.Slf4j;
import org.apache.commons.httpclient.DefaultHttpMethodRetryHandler;
import org.apache.commons.httpclient.HttpClient;
import org.apache.commons.httpclient.methods.PostMethod;
import org.apache.commons.httpclient.methods.RequestEntity;
import org.apache.commons.httpclient.methods.StringRequestEntity;
import org.apache.commons.httpclient.params.HttpMethodParams;
import org.apache.http.HttpEntity;
import org.apache.http.HttpStatus;
import org.apache.http.client.config.RequestConfig;
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.ContentType;
import org.apache.http.entity.mime.MultipartEntityBuilder;
import org.apache.http.entity.mime.content.StringBody;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClients;

import org.apache.http.util.EntityUtils;
import org.springframework.web.multipart.MultipartFile;


import java.io.*;
import java.nio.charset.StandardCharsets;

/**
 * @Author qymeng
 * @Date 2021/10/25
 * @Description 接口转发的工具类
 */
@Slf4j
public class TranspondUtils {

    /**
     * POST请求
     *
     * @param json 请求的json体
     * @param url  请求的url地址
     */
    public static String doPost(String json, String url) {
        HttpClient httpClient = new HttpClient();
        // 设置http连接主机服务超时时间
        httpClient.getHttpConnectionManager().getParams().setConnectionTimeout(35000);
        PostMethod postMethod = new PostMethod(url);
        // 设置post请求超时
        postMethod.getParams().setParameter(HttpMethodParams.SO_TIMEOUT, 60000);
        // 设置请求重试机制，默认重试次数：3次，参数设置为true，重试机制可用，false相反
        postMethod.getParams().setParameter(HttpMethodParams.RETRY_HANDLER, new DefaultHttpMethodRetryHandler(3, true));

        String result = null;
        try {
            RequestEntity entity = new StringRequestEntity(json, "application/json", "UTF-8");

            //请求头信息
            postMethod.setRequestHeader("Content-Type", "application/json");
            postMethod.setRequestEntity(entity);
            httpClient.executeMethod(postMethod);
            if (postMethod.getStatusCode() == HttpStatus.SC_OK) {
                // 获取响应输入流
                InputStream inStream = postMethod.getResponseBodyAsStream();
                BufferedReader reader = new BufferedReader(new InputStreamReader(inStream, StandardCharsets.UTF_8));
                StringBuilder strber = new StringBuilder();
                String line;
                while ((line = reader.readLine()) != null)
                    strber.append(line).append("\n");
                inStream.close();
                result = strber.toString();
            } else {
                throw new TranspondException("请求服务端失败，状态码不为200");
            }
        } catch (IOException e) {
            throw new TranspondException("请求服务端失败，地址为：" + url);
        } catch (IllegalStateException e) {
            throw new TranspondException("url地址不正确，该地址为：" + url);
        } catch (Exception e) {
            throw new TranspondException("其他异常");
        }
        return result;
    }

    public static String doPost(Object json, String url) {
        String s = JSON.toJSONString(json);
        return doPost(s, url);
    }

    /**
     * form-data 发送文件
     * @param url
     * @param file
     * @return
     */
    public static String httpPostFile(String url, MultipartFile file){
        CloseableHttpClient httpClient = HttpClients.createDefault();
        try {
            HttpPost httpPost = new HttpPost(url);
            MultipartEntityBuilder builder = MultipartEntityBuilder.create();
            String filename = file.getOriginalFilename();
            builder.addBinaryBody("file", file.getBytes(), ContentType.MULTIPART_FORM_DATA, filename);
//            StringBody fileName = new StringBody("文件名称", ContentType.MULTIPART_FORM_DATA);
//            builder.addPart("fileName", fileName);

            HttpEntity entity = builder.build();
            httpPost.setEntity(entity);
            CloseableHttpResponse response = httpClient.execute(httpPost);
            return EntityUtils.toString(response.getEntity(), "UTF-8");
        } catch (Exception e){
            e.printStackTrace();
        } finally {
            try {
                httpClient.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        return null;
    }


    /**
     * GET请求
     *
     * @param url 请求的url地址
     */
    public static String doGet(String url) {
        CloseableHttpClient httpClient = null;
        CloseableHttpResponse response = null;
        String result = "";
        try {
            // 通过址默认配置创建一个httpClient实例
            httpClient = HttpClients.createDefault();
            // 创建httpGet远程连接实例
            HttpGet httpGet = new HttpGet(url);
            // 设置配置请求参数
            RequestConfig requestConfig = RequestConfig.custom().setConnectTimeout(35000)// 连接主机服务超时时间
                    .setConnectionRequestTimeout(35000)// 请求超时时间
                    .setSocketTimeout(60000)// 数据读取超时时间
                    .build();
            // 为httpGet实例设置配置
            httpGet.setConfig(requestConfig);
            // 执行get请求得到返回对象
            response = httpClient.execute(httpGet);
            // 通过返回对象获取返回数据
            HttpEntity entity = response.getEntity();
            // 通过EntityUtils中的toString方法将结果转换为字符串
            result = EntityUtils.toString(entity);
//            log.info("请求服务器成功");
        } catch (IOException e) {
            throw new TranspondException("GET请求异常, URL为：" + url);
        } finally {
            // 关闭资源
            if (null != response) {
                try {
                    response.close();
                } catch (IOException e) {
                    throw new TranspondException("关闭CloseableHttpResponse时出现异常, URL为：" + url);
                }
            }
            if (null != httpClient) {
                try {
                    httpClient.close();
                } catch (IOException e) {
                    throw new TranspondException("关闭CloseableHttpClient时出现异常, URL为：" + url);
                }
            }
        }
        return result;
    }
    public static JSONObject doGetJson(String url) {
        return JSONObject.parseObject(doGet(url));
    }

    /**
     * 检测运行备用方案，检测http状态码
     * @param json
     * @param url
     * @return
     */
    public static boolean isRunning(String json, String url){
        HttpClient httpClient = new HttpClient();
        // 设置http连接主机服务超时时间
        httpClient.getHttpConnectionManager().getParams().setConnectionTimeout(35000);
        PostMethod postMethod = new PostMethod(url);
        // 设置post请求超时
        postMethod.getParams().setParameter(HttpMethodParams.SO_TIMEOUT, 60000);
        // 设置请求重试机制，默认重试次数：3次，参数设置为true，重试机制可用，false相反
        postMethod.getParams().setParameter(HttpMethodParams.RETRY_HANDLER, new DefaultHttpMethodRetryHandler(3, true));

        try {
            RequestEntity entity = new StringRequestEntity(json, "application/json", "UTF-8");
            //请求头信息
            postMethod.setRequestHeader("Content-Type", "application/json");
            postMethod.setRequestEntity(entity);
            httpClient.executeMethod(postMethod);
            return postMethod.getStatusCode() == HttpStatus.SC_OK;
        } catch (IOException e) {
            throw new TranspondException("请求服务端失败，地址为：" + url);
        } catch (IllegalStateException e) {
            throw new TranspondException("url地址不正确，该地址为：" + url);
        } catch (Exception e) {
            throw new TranspondException("其他异常");
        }
    }

}