RestTemplat发送HTTP请求

Posted 2023-02-19 l_learning

RestTemplate 是一个 spring-web 提供的执行HTTP请求的同步阻塞式工具类。
RestTemplate默认是使用SimpleClientHttpRequestFactory，内部是调用jdk的HttpConnection，默认超时为-1

1. 添加 Maven 坐标

<dependency>
	<groupId>org.springframework.boot</groupId>
	<artifactId>spring-boot-starter-web</artifactId>
</dependency>

2. RestTemplate 配置

import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.http.client.ClientHttpRequestFactory;
import org.springframework.http.client.HttpComponentsClientHttpRequestFactory;
import org.springframework.http.client.OkHttp3ClientHttpRequestFactory;
import org.springframework.web.client.RestTemplate;

import java.util.concurrent.TimeUnit;

@Configuration
public class RestTemplateConfig 

    /**
     * 没有实例化RestTemplate时，初始化RestTemplate
     * RestTemplate默认是使用SimpleClientHttpRequestFactory，
     * 内部是调用jdk的HttpConnection，默认超时为-1
     * @return
     */
    @ConditionalOnMissingBean(RestTemplate.class)
    @Bean
    public RestTemplate restTemplate()
        RestTemplate restTemplate = new RestTemplate();
        return restTemplate;
    

    /**
     * 使用HttpClient作为底层客户端
     * @return
     */
//    private ClientHttpRequestFactory getClientHttpRequestFactory() 
//        int timeout = 5000;
//        RequestConfig config = RequestConfig.custom()
//                .setConnectTimeout(timeout)
//                .setConnectionRequestTimeout(timeout)
//                .setSocketTimeout(timeout)
//                .build();
//        CloseableHttpClient client = HttpClientBuilder
//                .create()
//                .setDefaultRequestConfig(config)
//                .build();
//        return new HttpComponentsClientHttpRequestFactory(client);
//    


    /**
     * 使用OkHttpClient作为底层客户端
     * @return
     */
//    private ClientHttpRequestFactory getClientHttpRequestFactory()
//        OkHttpClient okHttpClient = new OkHttpClient.Builder()
//                .connectTimeout(5, TimeUnit.SECONDS)
//                .writeTimeout(5, TimeUnit.SECONDS)
//                .readTimeout(5, TimeUnit.SECONDS)
//                .build();
//        return new OkHttp3ClientHttpRequestFactory(okHttpClient);
//    

3. 请求测试接口 TestController，FileController

TestController

import com.alibaba.fastjson.JSON;
import com.example.demo.req.UserReq;
import com.example.demo.res.GlobalResult;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.*;

@Controller
public class TestController 

    /**
     * 无参get请求
     * @return
     */
    @RequestMapping(value = "testGet", method = RequestMethod.GET)
    @ResponseBody
    public GlobalResult testGet()
        GlobalResult result = new GlobalResult();
        result.setCode("200");
        result.setMsg("success，method：testGet");
        return result;
    

    /**
     * 带参的get请求
     * @return
     */
    @RequestMapping(value = "testGet2/id/name", method = RequestMethod.GET)
    @ResponseBody
    public GlobalResult testGetByRestFul(@PathVariable(value = "id") String id, @PathVariable(value = "name") String name)
        GlobalResult result = new GlobalResult();
        result.setCode("200");
        result.setMsg(String.format("success，method：testGet2，id：%s name：%s", id, name));
        return result;
    

    /**
     * 带参的get请求
     * 占位符号传参
     * @return
     */
    @RequestMapping(value = "testGetByParam", method = RequestMethod.GET)
    @ResponseBody
    public GlobalResult testGetByParam(@RequestParam("userName") String userName,
                                       @RequestParam("userPwd") String userPwd)
        GlobalResult result = new GlobalResult();
        result.setCode("200");
        result.setMsg(String.format("success，method：testGetByParam，userName：%s,userPwd：%s",  userName , userPwd));
        return result;
    


    /**
     * post表单请求
     * @return
     */
    @RequestMapping(value = "testPostByForm", method = RequestMethod.POST)
    @ResponseBody
    public GlobalResult testPostByForm(@RequestParam("userName") String userName,
                                       @RequestParam("userPwd") String userPwd)
        GlobalResult result = new GlobalResult();
        result.setCode("200");
        result.setMsg(String.format("success，method：testPostByForm，userName：%s,userPwd：%s",  userName , userPwd));
        return result;
    


    /**
     * post表单请求
     * @param userReq
     * @return
     */
    @RequestMapping(value = "testPostByFormAndObj", method = RequestMethod.POST)
    @ResponseBody
    public GlobalResult testPostByForm(UserReq userReq)
        GlobalResult result = new GlobalResult();
        result.setCode("200");
        result.setMsg(String.format("success，method：testPostByFormAndObj，json：%s",  JSON.toJSONString(userReq)));
        return result;
    

    /**
     * post请求 JSON
     * @param userReq
     * @return
     */
    @RequestMapping(value = "testPostByJson", method = RequestMethod.POST)
    @ResponseBody
    public GlobalResult testPostByJson(@RequestBody UserReq userReq)
        GlobalResult result = new GlobalResult();
        result.setCode("200");
        result.setMsg(String.format("success，method：testPostByJson，json：%s",  JSON.toJSONString(userReq)));
        return result;
    

    /**
     * put请求 JSON
     * @param userReq
     * @return
     */
    @RequestMapping(value = "testPutByJson", method = RequestMethod.PUT)
    @ResponseBody
    public void testPutByJson(@RequestBody UserReq userReq)
        System.out.println(String.format("success，method：testPutByJson，param：%s",  JSON.toJSONString(userReq)));
    

    /**
     * delete请求 JSON
     * @return
     */
    @RequestMapping(value = "testDeleteByJson", method = RequestMethod.DELETE)
    @ResponseBody
    public void testDeleteByJson()
        System.out.println("success，method：testDeleteByJson");
    

    /**
     * 重定向
     * @param userReq
     * @return
     */
    @RequestMapping(value = "testPostByLocation", method = RequestMethod.POST)
    public String testPostByLocation(@RequestBody UserReq userReq)
        return "redirect:index.html";
    

FileController

import com.example.demo.res.GlobalResult;
import org.springframework.util.FileCopyUtils;
import org.springframework.web.bind.annotation.*;
import org.springframework.web.multipart.MultipartFile;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.net.URLEncoder;
import java.util.UUID;

@RestController
public class FileController 

    private static final String UPLOAD_PATH = "/home/cms/file/";

    /**
     * 文件上传
     * @param uploadFile
     * @return
     */
    @RequestMapping(value = "upload", method = RequestMethod.POST)
    public GlobalResult upload(@RequestParam("uploadFile") MultipartFile uploadFile,
                               @RequestParam("userName") String userName) 
        // 在 uploadPath 文件夹中通过用户名对上传的文件归类保存
        File folder = new File(UPLOAD_PATH + userName);
        if (!folder.isDirectory()) 
            folder.mkdirs();
        

        // 对上传的文件重命名，避免文件重名
        String oldName = uploadFile.getOriginalFilename();
        String newName = UUID.randomUUID().toString() + oldName.substring(oldName.lastIndexOf("."));

        //定义返回视图
        GlobalResult result = new GlobalResult();
        try 
            // 文件保存
            uploadFile.transferTo(new File(folder, newName));
            result.setCode("200");
            result.setMsg("文件上传成功，方法：upload，文件名：" + newName);
         catch (IOException e) 
            e.printStackTrace();
            result.setCode("500");
            result.setMsg("文件上传失败，方法：upload，请求文件：" + oldName);
        
        return result;
    


    /**
     * 带参的get请求(restful风格)
     * @return
     */
    @RequestMapping(value = "downloadFile/userName/fileName", method = RequestMethod.GET)
    public void downloadFile(@PathVariable(value = "userName") String userName,
                             @PathVariable(value = "fileName") String fileName,
                             HttpServletRequest request,
                             HttpServletResponse response) throws Exception 

        File file = new File(UPLOAD_PATH + userName + File.separator + fileName);
        if (file.exists()) 
            //获取文件流
            FileInputStream fis = new FileInputStream(file);
            //获取文件后缀（.png）
            String extendFileName = fileName.substring(fileName.lastIndexOf('.'));
            //动态设置响应类型，根据前台传递文件类型设置响应类型
            response.setContentType(request.getSession().getServletContext().getMimeType(extendFileName));
            //设置响应头,attachment表示以附件的形式下载，inline表示在线打开
            response.setHeader("content-disposition","attachment;fileName=" + URLEncoder.encode(fileName,"UTF-8"));
            //获取输出流对象（用于写文件）
            OutputStream os = response.getOutputStream();
            //下载文件,使用spring框架中的FileCopyUtils工具
            FileCopyUtils.copy(fis,os);
        
    

用户请求参数对象 UserReq， 全局返回对象 GlobalResult

public class UserReq 

    private String userName;

    private String userPwd;

    //GET and SET  and  toString()

public class GlobalResult 

    private String code;

    private String msg;

    //GET and SET  and  toString()

4. RestTemplate使用示例

import com.example.demo.req.UserReq;
import com.example.demo.res.GlobalResult;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.core.io.FileSystemResource;
import org.springframework.http.*;
import org.springframework.test.context.junit4.SpringRunner;
import org.springframework.util.LinkedMultiValueMap;
import org.springframework.util.MultiValueMap;
import org.springframework.web.client.RequestCallback;
import org.springframework.web.client.RestTemplate;
import java.io.File;
import java.io.IOException;
import java.net.URI;
import java.nio.file.Files;
import java.nio.file.Paths;
import java.util.Arrays;
import java.util.HashMap;
import java.util.Map;
import java.util.Objects;

@RunWith(SpringRunner.class)
@SpringBootTest
public class RestTemplateTest 

    @Autowired
    private RestTemplate restTemplate;

    /**
     * 不带参的get请求
     */
    @Test
    public void testGet()
        String url = "http://localhost:8080/testGet";
        //发起请求
        GlobalResult responseBean = restTemplate.getForObject(url, GlobalResult.class);
        System.out.println(responseBean.toString());
    

    /**
     * 带参的get请求
     */
    @Test
    public void testGet2()
        String url = "http://localhost:8080/testGet2/1/2";
        //发起请求
        GlobalResult responseBean = restTemplate.getForObject(url, GlobalResult.class, "001", "张三");
        System.out.println(responseBean.toString());
    

    /**
     * 带参的get请求
     */
    @Test
    public void testGetByParam()
        String url = "http://localhost:8080/testGetByParam?userName=userName&userPwd=userPwd";
        //请求参数
        Map<String, String> uriVariables = new HashMap<>();
        uriVariables.put("userName", "张三");
        uriVariables.put("userPwd", "123456");
        //发起请求（带参数请求）
        GlobalResult responseBean = restTemplate.getForObject(url, GlobalResult.class, uriVariables);
        System.out.println(responseBean.toString());
    

    /**
     * Get全部信息
     */
    @Test
    public void testAllGet()
        String url = "http://localhost:8080/testGet";
        //发起请求，返回全部信息
        ResponseEntity<GlobalResult> response = restTemplate.getForEntity(url, GlobalResult.class);
        // 获取响应体
        System.out.println("HTTP 响应body：" + response.getBody以上是关于RestTemplat发送HTTP请求的主要内容，如果未能解决你的问题，请参考以下文章
 
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