使用HTTP协议实现远程调用接口

1、引入maven依赖

        <dependency>
            <groupId>org.apache.httpcomponents</groupId>
            <artifactId>httpmime</artifactId>
        </dependency>

2、封装http工具类

package cn.toroot.bj.utils;

import org.apache.http.HttpEntity;
import org.apache.http.HttpHost;
import org.apache.http.HttpResponse;
import org.apache.http.client.config.RequestConfig;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.client.methods.HttpRequestBase;
import org.apache.http.conn.routing.HttpRoute;
import org.apache.http.entity.ContentType;
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.entity.mime.content.StringBody;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.impl.conn.PoolingHttpClientConnectionManager;
import org.apache.http.util.EntityUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.io.File;
import java.io.IOException;
import java.nio.charset.Charset;
import java.util.Map;

/**
 * @author Mr peng
 * Created on 2020-6-10 14:25:18.
 */
public class HttpUtil {

    private final static Logger logger = LoggerFactory.getLogger(HttpUtil.class);
    private static CloseableHttpClient httpClient;
    private static Charset UTF_8 = Charset.forName("UTF-8");
    private static RequestConfig requestConfig = RequestConfig.custom().setSocketTimeout(20000).setConnectTimeout(20000).build();

    static {
        PoolingHttpClientConnectionManager cm = new PoolingHttpClientConnectionManager();
        cm.setMaxTotal(200);
        cm.setDefaultMaxPerRoute(20);
        HttpHost localhost = new HttpHost("localhost", 80);
        cm.setMaxPerRoute(new HttpRoute(localhost), 50);

        httpClient = HttpClients.custom().setConnectionManager(cm).build();
    }

    public static String post(String url, String content) {
        logger.debug("{} - {}", url, content);
        HttpPost httppost = new HttpPost(url);
        httppost.setConfig(requestConfig);
        if (content != null) {
            HttpEntity httpEntity = new StringEntity(content, UTF_8);
            httppost.setEntity(httpEntity);
        }
        return execute(httppost);
    }

    public static String postFile(String url, String localFile, Map<String,String> stringParts) {
        logger.debug("{} - {}", url, localFile);
        HttpPost httppost = new HttpPost(url);
        httppost.setConfig(requestConfig);

        MultipartEntityBuilder build = MultipartEntityBuilder.create();
        build.setMode(HttpMultipartMode.BROWSER_COMPATIBLE); //以浏览器兼容模式运行，防止文件名乱码
        build.setCharset(Charset.forName("utf-8"));

        if(null != localFile && localFile.length() > 0){
            FileBody fileBody = new FileBody(new File(localFile));
            build.addPart("file",fileBody);
        }

        if(null != stringParts) {
            for (Map.Entry<String, String> entry : stringParts.entrySet()) {
                StringBody stringBody = new StringBody(entry.getValue(), ContentType.create("text/plain", UTF_8));
                build.addPart(entry.getKey(), stringBody);
            }
        }

        HttpEntity reqEntity = build.build();

        httppost.setEntity(reqEntity);
        return execute(httppost);
    }

    public static String postFile(String url, String localFile) {
        return postFile(url,localFile,null);
    }

    public static String post4GzipResponse(String url, String content) {
        logger.debug("{} - {}", url, content);
        HttpPost httppost = new HttpPost(url);
        httppost.setConfig(requestConfig);
        httppost.addHeader("Accept-Encoding", "gzip");
        if (content != null) {
            HttpEntity httpEntity = new StringEntity(content, UTF_8);
            httppost.setEntity(httpEntity);
        }
        return execute(httppost);
    }

    /**
     * 以JSON的格式发送请求
     *
     * @param url
     * @param content
     * @return
     */
    public static String postAsJson(String url, String content) {
        logger.debug("{} - {}", url, content);
        HttpPost httppost = new HttpPost(url);
        httppost.setConfig(requestConfig);
        HttpEntity httpEntity = new StringEntity(content, ContentType.APPLICATION_JSON);
        httppost.setEntity(httpEntity);
        return execute(httppost);
    }

    public static String get(String url) {
        HttpGet httpGet = new HttpGet(url);
        httpGet.setConfig(requestConfig);
        return execute(httpGet);
    }

    private static String execute(HttpRequestBase httpRequestBase) {
        String result = null;
        try {
            HttpResponse response = httpClient.execute(httpRequestBase);
            HttpEntity resEntity = response.getEntity();
            if (resEntity != null) {
                result = EntityUtils.toString(resEntity, UTF_8);
                EntityUtils.consume(resEntity);
                if (result.length() < 2000) {
                    logger.debug(result);
                } else {
                    if (logger.isTraceEnabled()) {
                        logger.trace(result);
                    }
                }
            }
        } catch (IOException e) {
            logger.error("", e);
        }
        return result;
    }


    public static void main(String[] args) {
        String res = HttpUtil.get("http://www.baidu.com");
        System.out.println("res = " + res);
    }

    /**
     * 将对象转换成json，用post方法发送给服务器
     * @param url
     * @param intface
     * @param param
     * @return
     */
    public static String sendPost(String url, String intface, Object param) {
        return postAsJson(url + intface,JsonUtils.obj2json(param));
    }
}