SpringBoot使用RestTemplate发送HTTP请求

这里统一使用resttemplate的exchange方法调用get、post请求，此方法可以请求所有方式（GET, HEAD, POST, PUT, PATCH, DELETE, OPTIONS, TRACE），不使用getForEntity或者postForEntity

package com.example.handlerinterceptor.sysuser.controller;

import com.example.handlerinterceptor.dto.AjaxResult;
import com.example.handlerinterceptor.sysuser.entity.SysUser;
import org.springframework.core.ParameterizedTypeReference;
import org.springframework.core.io.UrlResource;
import org.springframework.http.HttpEntity;
import org.springframework.http.HttpHeaders;
import org.springframework.http.HttpMethod;
import org.springframework.http.ResponseEntity;
import org.springframework.util.linkedMultiValueMap;
import org.springframework.util.MultiValueMap;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.client.RestTemplate;

import javax.annotation.Resource;
import java.io.InputStream;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLConnection;
import java.util.HashMap;
import java.util.Map;

@RestController
public class Test {

    @Resource
    private RestTemplate restTemplate;

    private final String url = "http://127.0.0.1:80/test";

    
    @GetMapping("/getMethod")
    public void getMethod() {
        Map map = new HashMap<>(16);
        map.put("name", "fisher");
        map.put("age", 18);
        HttpHeaders headers = new HttpHeaders();
        // 可以设置bear token
        headers.setBearerAuth("123");
        // 也可以设置basic token
        headers.setBasicAuth("username", "pwd");
        HttpEntity httpEntity = new HttpEntity<>(null, headers);
        ResponseEntity exchange = restTemplate.exchange(url + "/getMethod?name={name}&age={age}",
            HttpMethod.GET, httpEntity, String.class, map);
        System.out.println(exchange);
        // 可以得到返回体的header
        System.out.println(exchange.getHeaders());
    }

    
    @PostMapping("/postMethod")
    public void postMethod() {
        HttpHeaders headers = new HttpHeaders();
        SysUser sysUser = new SysUser();
        sysUser.setName("fisher");
        sysUser.setAge(18);
        HttpEntity httpEntity = new HttpEntity<>(sysUser, headers);
        ResponseEntity> exchange = restTemplate.exchange(url + "/postMethod", HttpMethod.POST,
            httpEntity, new ParameterizedTypeReference<>() {});
        AjaxResult body = exchange.getBody();
        SysUser data = body.getData();
        System.out.println(data);
        System.out.println(exchange);
    }

    
    @PostMapping("/postMethod2")
    public void postMethod2() {
        HttpHeaders headers = new HttpHeaders();
        SysUser sysUser = new SysUser();
        sysUser.setName("fisher");
        sysUser.setAge(18);
        HttpEntity httpEntity = new HttpEntity<>(sysUser, headers);
        ResponseEntity exchange =
            restTemplate.exchange(url + "/postMethod2", HttpMethod.POST, httpEntity, SysUser.class);
        SysUser data = exchange.getBody();
        System.out.println(data);
        System.out.println(exchange);
    }

    
    @PostMapping("/upload")
    public void upload() throws MalformedURLException {
        String pic = "https://img-blog.csdnimg.cn/1cf5d00045f248808b0cd38f7dd1b4b6.png";
        if (getRource(pic)) {
            HttpHeaders headers = new HttpHeaders();
            MultiValueMap param = new linkedMultiValueMap<>();
            URL urll = new URL(pic);
            UrlResource urlResource = new UrlResource(urll);
            param.add("file", urlResource);
            HttpEntity> httpEntity = new HttpEntity<>(param, headers);
            ResponseEntity exchange =
                    restTemplate.exchange(url + "/upload", HttpMethod.POST, httpEntity, String.class);
            System.out.println(exchange);
        }else {
            System.out.println("图片不存在");
        }

    }

    
    public boolean getRource(String source) {
        try {
            URL url = new URL(source);
            URLConnection uc = url.openConnection();
            InputStream in = uc.getInputStream();
            if (source.equalsIgnoreCase(uc.getURL().toString())) {
                in.close();
            }
            return true;
        } catch (Exception e) {
            return false;
        }
    }
}