在java后端发送HTTPClient请求

简介

HttpClient
遵循http协议的客户端编程工具包
支持最新的http协议

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部分依赖自动传递依赖了HttpClient的jar包

明明项目中没有引入 HttpClient 的Maven坐标，但是却可以直接使用HttpClient
原因是：阿里云的sdk依赖中传递依赖了HttpClient的jar包

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发送get请求

    @Test
    public void testGet() {
        // 创建HttpGet对象
        HttpGet httpGet = new HttpGet("http://localhost:8080/user/shop/status");
        // 创建HttpClient对象 用于发送请求
        // try-with-resources 语法 需要关闭的资源分别是 httpClient response
        try (CloseableHttpClient httpClient = HttpClients.createDefault();
             CloseableHttpResponse response = httpClient.execute(httpGet)) {
            // 获取响应状态码
            int statusCode = response.getStatusLine().getStatusCode();
            System.out.println("响应状态码：" + statusCode); //响应状态码：200
            // 获取响应数据
            HttpEntity entity = response.getEntity();
            String result = EntityUtils.toString(entity);
            System.out.println("响应数据：" + result); // 响应数据：{"code":1,"msg":null,"data":1}
        } catch (IOException e) {
            log.error("请求失败", e);
            e.printStackTrace();
        }
    }

发送post请求

    /**
     * 测试HttpClient 发送post请求 需要提前启动项目 不然请求不到
     */
    @Test
    public void testPost() {
        // 创建HttpPost对象
        HttpPost httpPost = new HttpPost("http://localhost:8080/admin/employee/login");
        // 这个请求是有请求体的
        // 使用JsonObject构建请求体  更加高效简洁
        JsonObject jsonObject = new JsonObject();
        jsonObject.addProperty("username", "admin");
        jsonObject.addProperty("password", "123456");
        // 将json对象转为字符串 并设置编码格式 设置传输的数据格式 使用构造器和set方法都是可以设置的
        StringEntity stringEntity = null;
        try {
            stringEntity = new StringEntity(jsonObject.toString());
            stringEntity.setContentEncoding("UTF-8");
            stringEntity.setContentType("application/json");
        } catch (UnsupportedEncodingException e) {
            throw new RuntimeException(e);
        }
        // 设置请求体
        httpPost.setEntity(stringEntity);

        // 创建HttpClient对象 用于发送请求
        // try-with-resources 语法 需要关闭的资源分别是 httpClient response
        try (CloseableHttpClient httpClient = HttpClients.createDefault();
             CloseableHttpResponse response = httpClient.execute(httpPost)) {
            // 获取响应状态码
            int statusCode = response.getStatusLine().getStatusCode();
            System.out.println("响应状态码：" + statusCode); //响应状态码：200
            // 获取响应数据
            HttpEntity entity = response.getEntity();
            String result = EntityUtils.toString(entity);
            System.out.println("响应数据：" + result); // 响应数据：{"code":1,"msg":null,"data":{"id":1,"userName":"admin","name":"管理员","token":"eyJhbGciOiJIUzI1NiJ9.eyJlbXBJZCI6MSwiZXhwIjoxNzI4MzgwOTk5fQ.Rm7UWZbDEU_06DJLfegcP31n-9g8AB-Jxa-49Zw-ttM"}}
        } catch (IOException e) {
            log.error("请求失败", e);
            e.printStackTrace();
        }
    }

工具类

分装了一个工具类

发送get请求
使用form表单发送post请求
使用json对象发送post请求

package com.sky.utils;

import com.alibaba.fastjson.JSONObject;
import lombok.extern.slf4j.Slf4j;
import org.apache.http.NameValuePair;
import org.apache.http.client.config.RequestConfig;
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.CloseableHttpClient;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.message.BasicNameValuePair;
import org.apache.http.util.EntityUtils;

import java.io.IOException;
import java.net.URI;
import java.net.URISyntaxException;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;

/**
 * Http工具类
 */
@Slf4j
public class HttpClientUtil {

    static final int TIMEOUT_MSEC = 5 * 1000;
    public static final String UTF_8 = "utf-8";
    public static final String DEFAULT_CONTENT_TYPE = "application/json";
    public static final String LOG_ERR_TEMPLATE = "{}路径请求出错，错误详情如下";

    /**
     * 发送GET请求，返回字符串
     */
    public static String doGet(String url, Map<String, String> paramMap) throws URISyntaxException, IOException {
        String result = "";

        try (CloseableHttpClient httpClient = HttpClients.createDefault()) {
            URIBuilder builder = new URIBuilder(url);
            if (paramMap != null) {
                for (String key : paramMap.keySet()) {
                    builder.addParameter(key, paramMap.get(key));
                }
            }
            URI uri = builder.build();

            // 创建GET请求
            HttpGet httpGet = new HttpGet(uri);

            // 发送请求
            try (CloseableHttpResponse response = httpClient.execute(httpGet)) {
                // 判断响应状态
                if (response.getStatusLine().getStatusCode() == 200) {
                    result = EntityUtils.toString(response.getEntity(), UTF_8);
                }
            }
        } catch (Exception e) {
            // 日志记录
            logErr(url);
            throw e;
        }

        return result;
    }

    /**
     * 发送GET请求，返回JSONObject
     */
    public static JSONObject doGetJson(String url, Map<String, String> paramMap) throws URISyntaxException, IOException {
        JSONObject result = null;

        try (CloseableHttpClient httpClient = HttpClients.createDefault()) {
            URIBuilder builder = new URIBuilder(url);
            if (paramMap != null) {
                for (String key : paramMap.keySet()) {
                    builder.addParameter(key, paramMap.get(key));
                }
            }
            URI uri = builder.build();

            // 创建GET请求
            HttpGet httpGet = new HttpGet(uri);

            // 发送请求
            try (CloseableHttpResponse response = httpClient.execute(httpGet)) {
                // 判断响应状态
                if (response.getStatusLine().getStatusCode() == 200) {
                    String resultString = EntityUtils.toString(response.getEntity(), UTF_8);
                    result = JSONObject.parseObject(resultString);
                }
            }
        } catch (Exception e) {
            logErr(url);
            throw e;
        }

        return result;
    }



    /**
     * 发送POST请求，返回字符串 表单请求
     */
    public static String doPost(String url, Map<String, String> paramMap) throws IOException {
        String resultString = "";

        try (CloseableHttpClient httpClient = HttpClients.createDefault()) {
            // 创建Http Post请求
            HttpPost httpPost = new HttpPost(url);

            // 创建参数列表
            if (paramMap != null) {
                List<NameValuePair> paramList = new ArrayList<>();
                for (Map.Entry<String, String> param : paramMap.entrySet()) {
                    paramList.add(new BasicNameValuePair(param.getKey(), param.getValue()));
                }
                // 模拟表单
                UrlEncodedFormEntity entity = new UrlEncodedFormEntity(paramList);
                httpPost.setEntity(entity);
            }

            httpPost.setConfig(builderRequestConfig());

            // 执行http请求
            try (CloseableHttpResponse response = httpClient.execute(httpPost)) {
                resultString = EntityUtils.toString(response.getEntity(), UTF_8);
            }
        } catch (Exception e) {
            logErr(url);
            throw e;
        }

        return resultString;
    }

    /**
     * 发送POST请求，返回JSONObject 表单请求
     */
    public static JSONObject doPostJson(String url, Map<String, String> paramMap) throws IOException {
        JSONObject result = null;

        try (CloseableHttpClient httpClient = HttpClients.createDefault()) {
            // 创建Http Post请求
            HttpPost httpPost = new HttpPost(url);

            // 创建参数列表
            if (paramMap != null) {
                List<NameValuePair> paramList = new ArrayList<>();
                for (Map.Entry<String, String> param : paramMap.entrySet()) {
                    paramList.add(new BasicNameValuePair(param.getKey(), param.getValue()));
                }
                // 模拟表单
                UrlEncodedFormEntity entity = new UrlEncodedFormEntity(paramList);
                httpPost.setEntity(entity);
            }

            httpPost.setConfig(builderRequestConfig());

            // 执行http请求
            try (CloseableHttpResponse response = httpClient.execute(httpPost)) {
                String resultString = EntityUtils.toString(response.getEntity(), UTF_8);
                result = JSONObject.parseObject(resultString);
            }
        } catch (Exception e) {
            logErr(url);
            throw e;
        }

        return result;
    }

    /**
     * 发送POST请求，JSON格式数据，返回字符串 json请求
     */
    public static String doPost4Json(String url, Map<String, String> paramMap) throws IOException {
        String resultString = "";

        try (CloseableHttpClient httpClient = HttpClients.createDefault()) {
            HttpPost httpPost = new HttpPost(url);

            if (paramMap != null) {
                // 构造json格式数据
                JSONObject jsonObject = new JSONObject();
                for (Map.Entry<String, String> param : paramMap.entrySet()) {
                    jsonObject.put(param.getKey(), param.getValue());
                }
                StringEntity entity = new StringEntity(jsonObject.toString(), UTF_8);
                // 设置请求编码
                entity.setContentEncoding(UTF_8);
                // 设置数据类型
                entity.setContentType(DEFAULT_CONTENT_TYPE);
                httpPost.setEntity(entity);
            }

            httpPost.setConfig(builderRequestConfig());

            // 执行http请求
            try (CloseableHttpResponse response = httpClient.execute(httpPost)) {
                resultString = EntityUtils.toString(response.getEntity(), UTF_8);
            }
        } catch (Exception e) {
            logErr(url);
            throw e;
        }

        return resultString;
    }

    /**
     * 发送POST请求，JSON格式数据，返回JSONObject json请求
     */
    public static JSONObject doPost4JsonReturnJson(String url, Map<String, String> paramMap) throws IOException {
        JSONObject result = null;

        try (CloseableHttpClient httpClient = HttpClients.createDefault()) {
            HttpPost httpPost = new HttpPost(url);

            if (paramMap != null) {
                // 构造json格式数据
                JSONObject jsonObject = new JSONObject();
                for (Map.Entry<String, String> param : paramMap.entrySet()) {
                    jsonObject.put(param.getKey(), param.getValue());
                }
                StringEntity entity = new StringEntity(jsonObject.toString(), UTF_8);
                // 设置请求编码
                entity.setContentEncoding(UTF_8);
                // 设置数据类型
                entity.setContentType(DEFAULT_CONTENT_TYPE);
                httpPost.setEntity(entity);
            }

            httpPost.setConfig(builderRequestConfig());

            // 执行http请求
            try (CloseableHttpResponse response = httpClient.execute(httpPost)) {
                String resultString = EntityUtils.toString(response.getEntity(), UTF_8);
                result = JSONObject.parseObject(resultString);
            }
        } catch (Exception e) {
            logErr(url);
           throw e;
        }

        return result;
    }

    private static RequestConfig builderRequestConfig() {
        return RequestConfig.custom()
                .setConnectTimeout(TIMEOUT_MSEC)
                .setConnectionRequestTimeout(TIMEOUT_MSEC)
                .setSocketTimeout(TIMEOUT_MSEC).build();
    }


    /**
     * 日志报错
     * @param url 出错的URL
     */
    private static void logErr(String url) {
        log.error(LOG_ERR_TEMPLATE, url);
    }
}