Springboot-使用RestTemplate方式发HTTP请求及上传文件

RestTemplate是Spring提供的用于访问Rest服务的客户端，RestTemplate提供了多种便捷访问远程Http服务的方法,能够大大提高客户端的编写效率。

我基于RestTemplate编写了一个工具类，方便使用。工具类提供之提供了GET、POST、DELETE请求方法，其他方法自行补充

Application启动类中实例RestTemplate

@SpringBootApplication
@RestController
public class Application {
    public static void main(String[] args) {
        SpringApplication.run(ElasticApplication.class, args);
    }
    @Bean
    public RestTemplate restTemplate() {
        return new RestTemplate(new HttpComponentsClientHttpRequestFactory());
    }
}

RestTemplateUtils工具类

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.http.HttpEntity;
import org.springframework.http.HttpHeaders;
import org.springframework.http.HttpMethod;
import org.springframework.http.ResponseEntity;
import org.springframework.stereotype.Component;
import org.springframework.util.LinkedMultiValueMap;
import org.springframework.util.MultiValueMap;
import org.springframework.web.client.RestTemplate;

import java.util.ArrayList;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;

/**
 * RestTemplate工具类
 *
 * @author Colin.Ye
 * @version 1.0
 * @ClassName RestTemplateUtils
 * @date 2019/7/31
 **/
@Component
public class RestTemplateUtils {

    @Autowired
    private RestTemplate restTemplate;

    /**
     * POST请求-JSON参数
     *
     * @param url
     * @param params
     * @param headers
     * @return
     */
    public <T> T httpPostJson(String url, Map<String, Object> params, Map<String, String> headers, Class<T> clazz) {
        HttpHeaders httpHeaders = new HttpHeaders();
        if (headers != null) {
            headers.forEach((o1, o2) -> httpHeaders.add(o1, o2));
        }
        // json方式传参
        return restTemplate.postForObject(url, new HttpEntity(params, httpHeaders), clazz);
    }

    /**
     * POST请求-FROM参数
     *
     * @param url
     * @param params
     * @param headers
     * @return
     */
    public <T> T httpPostFrom(String url, Map<String, Object> params, Map<String, String> headers, Class<T> clazz) {
        HttpHeaders httpHeaders = new HttpHeaders();
        params = params == null ? new LinkedHashMap<>() : params;
        if (headers != null) {
            headers.forEach((o1, o2) -> httpHeaders.add(o1, o2));
        }
        MultiValueMap<String, Object> stringObjectLinkedMultiValueMap = new LinkedMultiValueMap<>();
        params.forEach((o1, o2) -> stringObjectLinkedMultiValueMap.add(o1, o2));
        // 表单方式传参
        // json方式传参
        return restTemplate.postForObject(url, new HttpEntity(stringObjectLinkedMultiValueMap, httpHeaders), clazz);
    }

    /**
     * GET请求-?号参数
     *
     * @param url
     * @param params
     * @param headers
     * @return
     */
    public <T> T httpGetTraditional(String url, Map<String, Object> params, Map<String, String> headers, Class<T> clazz) {
        HttpHeaders httpHeaders = new HttpHeaders();
        params = params == null ? new LinkedHashMap<>() : params;
        if (headers != null) {
            headers.forEach((o1, o2) -> httpHeaders.add(o1, o2));
        }
        StringBuilder sb = new StringBuilder(url);
        sb.append("?");
        params.forEach((o1, o2) -> sb.append(o1).append("=").append(o2).append("&"));
        url = sb.toString().replaceAll("&$+|\\?$+", "");
        ResponseEntity<T> exchange = restTemplate.exchange(url, HttpMethod.GET, new HttpEntity(null, httpHeaders), clazz);
        return exchange.getBody();
    }

    /**
     * GET请求-分隔符参数
     *
     * @param url
     * @param params LinkedHashMap
     * @param headers
     * @return
     */
    public <T> T httpGetPlaceholder(String url, List<String> params, Map<String, String> headers, Class<T> clazz) {
        HttpHeaders httpHeaders = new HttpHeaders();
        params = params == null ? new ArrayList<>() : params;
        if (headers != null) {
            headers.forEach((o1, o2) -> httpHeaders.add(o1, o2));
        }
        StringBuilder sb = new StringBuilder(url);
        params.forEach(o2 -> sb.append("/").append(o2));
        url = sb.toString().replaceAll("&$+|\\?$+", "");
        ResponseEntity<T> exchange = restTemplate.exchange(url, HttpMethod.GET, new HttpEntity(null, httpHeaders), clazz);
        return exchange.getBody();
    }

    /**
     * DELETE请求-?号参数
     *
     * @param url
     * @param params
     * @param headers
     * @return
     */
    public <T> T httpDeleteTraditional(String url, Map<String, Object> params, Map<String, String> headers, Class<T> clazz) {
        HttpHeaders httpHeaders = new HttpHeaders();
        params = params == null ? new LinkedHashMap<>() : params;
        if (headers != null) {
            headers.forEach((o1, o2) -> httpHeaders.add(o1, o2));
        }
        StringBuilder sb = new StringBuilder(url);
        sb.append("?");
        params.forEach((o1, o2) -> sb.append(o1).append("=").append(o2).append("&"));
        url = sb.toString().replaceAll("&$+|\\?$+", "");
        ResponseEntity<T> exchange = restTemplate.exchange(url, HttpMethod.DELETE, new HttpEntity(null, httpHeaders), clazz);
        return exchange.getBody();
    }

    /**
     * DELETE请求-分隔符参数
     *
     * @param url
     * @param params
     * @param headers
     * @return
     */
    public <T> T httpDeletePlaceholder(String url, List<String> params, Map<String, String> headers, Class<T> clazz) {
        HttpHeaders httpHeaders = new HttpHeaders();
        params = params == null ? new ArrayList<>() : params;
        if (headers != null) {
            headers.forEach((o1, o2) -> httpHeaders.add(o1, o2));
        }
        StringBuilder sb = new StringBuilder(url);
        params.forEach(o2 -> sb.append("/").append(o2));
        url = sb.toString().replaceAll("&$+|\\?$+", "");
        ResponseEntity<T> exchange = restTemplate.exchange(url, HttpMethod.DELETE, new HttpEntity(null, httpHeaders), clazz);
        return exchange.getBody();
    }
}

使用

/**
 * @author Colin.Ye
 * @version 1.0
 * @ClassName LowCreateIndexDemo
 * @date 2019/3/13
 **/
@RestController
@RequestMapping("/lowClient/v1/")
@CrossOrigin
@DefaultProperties(defaultFallback = "defaultFallback")
public class LowCreateIndexDemo extends BaseController {

    @Autowired
    private RestTemplateUtils restTemplateUtils;

    @RequestMapping("/index")
    @Log
    @HystrixCommand(commandProperties = @HystrixProperty(name = "execution.isolation.thread.timeoutInMilliseconds", value = "2000"))

    public String index() {
        Map<String, Object> params = new HashMap<>();
        //  上传文件
        FileSystemResource resource = new FileSystemResource(new File("/Users/yezhuang/Documents/data/oracle命令的副本.txt"));
        params.put("deviceId", "123424");
        params.put("file", resource);
        Object o = restTemplateUtils.httpPostFrom("http://localhost:10005/lowClient/v1/test", params, null, String.class);
        return o.toString();
    }

    @RequestMapping("/test")
    public String remoteUpdteTest(String deviceId, @RequestParam MultipartFile file) {
        System.out.println(deviceId);
        System.out.println(file.getName());
        return "success";
    }

    private String fallback() {
        return "网络开小差了，请稍后重试···";
    }

    private String defaultFallback() {
        return "defaultFallback: 网络开小差了，请稍后重试···";
    }
}