HttpClient使用及工具类

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一、依赖

主要是两个包，发起连接的httpclient以及定义http请求数据类型的包httpmime

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

二、封装工具类

把常用的功能封装成工具类

package org.colin;

import org.apache.http.HttpEntity;
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.MultipartEntityBuilder;
import org.apache.http.impl.client.HttpClientBuilder;
import org.apache.http.message.BasicNameValuePair;

import javax.net.ssl.SSLContext;
import javax.net.ssl.TrustManager;
import javax.net.ssl.X509TrustManager;
import java.io.*;
import java.security.KeyManagementException;
import java.security.NoSuchAlgorithmException;
import java.security.cert.CertificateException;
import java.security.cert.X509Certificate;
import java.util.*;
import java.util.stream.Collectors;

/**
 * httpClient常用功能封装
 */
public class HttpClientUtil {


    /**
     * 将http请求结果的内容读取成字符串
     *
     * @param response
     * @return
     * @throws IOException
     */
    public static String parseRespToStr(CloseableHttpResponse response) throws IOException {
        ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
        response.getEntity().writeTo(outputStream);
        return outputStream.toString();
    }

    /**
     * 创建formData的httpPost请求
     * content-type 对应 multipart/form-data
     *
     * @param url post地址
     * @param headers 请求头内容
     * @param params 表单内容 map，value支持 String/File/Collection<File>
     * @return
     * @throws IOException
     */
    public static HttpPost createFormDataHttpPost(String url, Map<String, String> headers, Map<String, Object> params) throws IOException {
        HttpPost httpPost = new HttpPost(url);
        MultipartEntityBuilder builder = MultipartEntityBuilder.create();
        if(params != null) {
            params.forEach((k,v)->{
                if(v instanceof File) {
                    builder.addBinaryBody(k ,(File) v);
                } else if(v instanceof Collection) {
                    for (Object obj : (Collection)v) {
                        builder.addBinaryBody(k, (File)obj);
                    }
                } else {
                    builder.addTextBody(k, v.toString());
                }
            });
        }
        httpPost.setEntity(builder.build());
        if(headers != null) {
            headers.forEach(httpPost::addHeader);
        }
        return httpPost;
    }

    /**
     * 创建纯字符串的form表单，并进行url编码
     * content-type 对应 application/x-www-form-urlencoded
     *
     * @param url
     * @param headers
     * @param params
     * @return
     * @throws IOException
     */
    public static HttpPost createFormUrlencodedHttpPost(String url, Map<String, String> headers, Map<String, String> params) throws IOException {
        HttpPost httpPost = new HttpPost(url);
        List<BasicNameValuePair> nameValuePairs;
        if(params != null) {
            nameValuePairs = params.entrySet().stream().map(entry -> new BasicNameValuePair(entry.getKey(), entry.getValue()))
                    .collect(Collectors.toList());
        } else {
            nameValuePairs = new LinkedList<>();
        }
        HttpEntity entity = new UrlEncodedFormEntity(nameValuePairs);
        httpPost.setEntity(entity);
        if(headers != null) {
            headers.forEach(httpPost::addHeader);
        }
        return httpPost;
    }

    /**
     * 创建json格式的httpPost请求
     * content-type 对应 application/json
     *
     * @param url
     * @param headers
     * @param jsonStr
     * @return
     * @throws UnsupportedEncodingException
     */
    public static HttpPost createJsonHttpPost(String url, Map<String, String> headers, String jsonStr) throws UnsupportedEncodingException {
        HttpPost httpPost = new HttpPost(url);
        httpPost.setEntity(new StringEntity(jsonStr));
        if(headers != null) {
            headers.forEach(httpPost::addHeader);
        }
        return httpPost;
    }

    /**
     * 创建httpGet请求
     *
     * @param url
     * @param headers
     * @return
     * @throws IOException
     */
    public static HttpGet createHttpGet(String url, Map<String, String> headers) throws IOException {
        HttpGet httpGet = new HttpGet(url);
        if(headers != null) {
            headers.forEach(httpGet::addHeader);
        }
        return httpGet;
    }

    public static HttpClientBuilder getHttpClientBuilder() {
        return HttpClientBuilder.create();
    }

    public static HttpClientBuilder getHttpsClientBuilder() throws NoSuchAlgorithmException, KeyManagementException {
        SSLContext ctx = SSLContext.getInstance("TLS");
        X509TrustManager tm = new X509TrustManager() {
            @Override
            public void checkClientTrusted(X509Certificate[] chain,
                                           String authType) throws CertificateException {
            }
            @Override
            public void checkServerTrusted(X509Certificate[] chain,
                                           String authType) throws CertificateException {
            }
            @Override
            public X509Certificate[] getAcceptedIssuers() {
                return null;
            }
        };
        ctx.init(null, new TrustManager[]{tm}, null);
        return HttpClientBuilder.create().setSSLContext(ctx);
    }
}

三、测试类

package com.colin;

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.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClientBuilder;
import java.io.File;
import java.io.UnsupportedEncodingException;
import java.util.HashMap;
import java.util.LinkedList;
import java.util.Map;

public class Test {
    public static void main( String[] args ) throws UnsupportedEncodingException {
        HttpClientUtil app = new HttpClientUtil();
        try {
            String url = "http://127.0.0.1:8098/test";
            // 复用一个httpClient
            CloseableHttpClient client = HttpClientBuilder.create().build();
            // 1. get请求测试
            HttpGet get = app.createHttpGet(url + "?name=111&age=333", null);

            // 2. post请求测试 application/x-www-form-urlencoded
            Map<String, String> param = new HashMap<>();
            param.put("name", "321");
            param.put("age", "10");
            HttpPost postStr = app.createFormUrlencodedHttpPost(url, param, param);

            // 3. post请求测试，多文件上传 multipart/form-data
            Map<String, Object> params = new HashMap<>();
            params.put("name", "123");
            params.put("age", "10");
            LinkedList<Object> list = new LinkedList<>();
            list.add(new File("E:\\321.png"));
            list.add(new File("E:\\123.png"));
            params.put("photo", list);
            HttpPost postFormData1 = app.createFormDataHttpPost(url, null, params);

            // 4. post请求测试，单文件上传 multipart/form-data
            params = new HashMap<>();
            params.put("name", "123");
            params.put("age", "10");
            params.put("photo", new File("E:\\321.png"));
            HttpPost postFormData2 = app.createFormDataHttpPost(url, null, params);

            // 5. post请求测试，json格式 application/json
            HashMap<String, String> head = new HashMap<>();
            HttpPost postJson = app.createJsonHttpPost("http://127.0.0.1:8098/jsonTest", head, "{'name':'123', 'age':'333'}");

            // 发起请求
            CloseableHttpResponse response;
            response = client.execute(get);
            System.out.println("-------get---------");
            System.out.println(HttpClientUtil.parseRespToStr(response));

            response = client.execute(postStr);
            System.out.println("---------post str----------");
            System.out.println(HttpClientUtil.parseRespToStr(response));

            response = client.execute(postFormData1);
            System.out.println("---------post formData1----------");
            System.out.println(HttpClientUtil.parseRespToStr(response));

            response = client.execute(postFormData2);
            System.out.println("---------post formData2----------");
            System.out.println(HttpClientUtil.parseRespToStr(response));

            response = client.execute(postJson);
            System.out.println("---------post json----------");
            System.out.println(HttpClientUtil.parseRespToStr(response));
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

四、服务器接受的代码

@GetMapping("/test")
@ResponseBody
String getTest(String name, String age){
    System.out.println("name = " + name);
    System.out.println("age = " + age);
    return "getOk";
}

// 兼容接收多个文件，或者一个
@PostMapping("/test")
@ResponseBody
String postTest(String name, String age, @RequestParam(value = "photo", required = false) MultipartFile[] photo) {
    System.out.println("name = " + name);
    System.out.println("age = " + age);
    if(photo != null) {
        for (MultipartFile file : photo) {
            System.out.println("photo.getSize() = " + file.getSize());
            System.out.println("photo.getName() = " + file.getOriginalFilename());
        }
    }
    return "postOk";
}

@PostMapping("/jsonTest")
@ResponseBody
String jsonTest(@RequestBody String json) {
    System.out.println("json = " + json);
    return "postOk";
}

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