SpringBoot使用RestTemplate

初始化

        使用Configuration 加入IOC容器 的配置：

import com.alibaba.fastjson.support.spring.FastJsonHttpMessageConverter;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.http.client.SimpleClientHttpRequestFactory;
import org.springframework.http.converter.StringHttpMessageConverter;
import org.springframework.web.client.RestTemplate;

import java.nio.charset.StandardCharsets;

@Configuration
public class RestTemplateConfiguration {

    @Bean
    public RestTemplate restTemplate() {
        SimpleClientHttpRequestFactory requestFactory = 
                                    new SimpleClientHttpRequestFactory();
        // 设置连接超时，单位毫秒
        requestFactory.setConnectTimeout(30000);
        //设置读取超时
        requestFactory.setReadTimeout(30000);
        RestTemplate restTemplate = new RestTemplate();
        restTemplate.setRequestFactory(requestFactory);
        restTemplate.getMessageConverters().add(
                        new StringHttpMessageConverter(StandardCharsets.UTF_8)
        );
        restTemplate.getMessageConverters().add(
                        new FastJsonHttpMessageConverter()
        );
        return restTemplate;
    }
}

        如果想不加入IOC容器的话，可以使用如下单例方式。

import com.alibaba.fastjson.support.spring.FastJsonHttpMessageConverter;
import org.springframework.http.client.SimpleClientHttpRequestFactory;
import org.springframework.http.converter.StringHttpMessageConverter;
import org.springframework.web.client.RestTemplate;

import java.nio.charset.StandardCharsets;

public class RestTemplateProvider {

    private static final RestTemplate restTemplate = init();

    private RestTemplateProvider() {
    }

    public static RestTemplate getRestTemplate() {
        return restTemplate;
    }

    private static RestTemplate init() {
        SimpleClientHttpRequestFactory requestFactory =
                new SimpleClientHttpRequestFactory();
        // 设置连接超时，单位毫秒
        requestFactory.setConnectTimeout(30000);
        //设置读取超时
        requestFactory.setReadTimeout(30000);
        RestTemplate restTemplate = new RestTemplate();
        restTemplate.setRequestFactory(requestFactory);

        restTemplate.getMessageConverters().add(
                        new StringHttpMessageConverter(StandardCharsets.UTF_8)
        );
        restTemplate.getMessageConverters().add(
                        new FastJsonHttpMessageConverter()
        );
        return restTemplate;
    }
}

POST请求

（1）发送JSON格式

参数：

@Data
public class TaskDO {
    private String id;
}

客户端调用

TaskDO taskDO = new TaskDO(); 
taskDO.setId("20220113");  

String url = "http://localhost:8080/dispatch";

//或者使用Map也可以
//Map<String,Object> params = new HashMap<>();
//params.put("id","20220113");
//String result = restTempalte.postForObject(url , params, String.class);

String result = restTempalte.postForObject(url , taskDO, String.class);
//String.class是返回值，可以输入Object.class、Map.class等任何返回值，需要约定好哦
//Map result = restTempalte.postForObject(url , taskDO, Map.class);
//Object result = restTempalte.postForObject(url , taskDO, Object.class);
//Response result = restTempalte.postForObject(url , taskDO, Response.class);

Controller接收

@PostMapping("/dispatch")
    public SingleResponse function(@RequestBody @Valid TaskDO params) {
        LOGGER.info("参数是:{}", params);
        jobTask.executeTask(params);
        return SingleResponse.of("成功");
    }

（2）发送普通表单格式

@Data
public class TaskDO {
    private String id;
    private String taskName;
}

客户端调用 

import org.springframework.http.HttpEntity;
import org.springframework.http.HttpHeaders;
import org.springframework.http.MediaType;
import org.springframework.util.LinkedMultiValueMap;
import org.springframework.util.MultiValueMap;

String url = "http://localhost:8080/dispatch";

HttpHeaders headers = new HttpHeaders();
headers.setContentType(MediaType.APPLICATION_FORM_URLENCODED);
//提交参数设置
MultiValueMap<String, String> map = new LinkedMultiValueMap<>();
map.add("id", "20220113");
map.add("taskName", "我的任务");

 // 组装请求体
HttpEntity<MultiValueMap<String, String>> request = new HttpEntity<>(map, headers);
String result = restTempalte.postForObject(url, request, String.class);

System.out.println(result);

Controller接收

@PostMapping("/dispatch")
    public SingleResponse function(TaskDO params) {
        LOGGER.info("参数是:{}", params);
        return SingleResponse.of("成功");
    }

（3）上传文件

private static RestTemplate init() {
        SimpleClientHttpRequestFactory requestFactory =
                new SimpleClientHttpRequestFactory();
        // 设置连接超时，单位毫秒
        requestFactory.setConnectTimeout(30000);
        //设置读取超时
        requestFactory.setReadTimeout(30000);
        RestTemplate restTemplate = new RestTemplate();
        restTemplate.setRequestFactory(requestFactory);

        restTemplate.getMessageConverters().add(new StringHttpMessageConverter(StandardCharsets.UTF_8));
        restTemplate.getMessageConverters().add(new FastJsonHttpMessageConverter());
        return restTemplate;
    }

import org.springframework.http.*;
import org.springframework.util.LinkedMultiValueMap;
import org.springframework.util.MultiValueMap;
import org.springframework.web.client.RestTemplate;
import org.springframework.core.io.FileSystemResource;

MultiValueMap<String,Object> parts = new LinkedMultiValueMap<>();
parts.add("file", new FileSystemResource(new File("C:\\test.txt")));
parts.add("num", 5);
parts.add("flag", true);

String url = "http://localhost:8080/upload";
HttpHeaders headers = new HttpHeaders();
headers.setContentType(MediaType.MULTIPART_FORM_DATA);

HttpEntity<MultiValueMap<String,Object>> request = new HttpEntity<>(parts, headers);
ResponseEntity<String> entity = 
            restTemplate.exchange(url, HttpMethod.POST, request, String.class);

System.out.println(entity.getBody());

@Data
public class UploadCmd implements Serializable {

    private Integer num;
    private Boolean flag;
    private MultipartFile file;
}

@PostMapping(value = "/upload")
public Response upload(UploadCmd upload) throws IOException {
    ...
}

GET请求

GET请求的参数使用 {} 占位，注意，是{} ，不是 ${}

@Data
public class TaskDO {
    private String taskName;
    private Integer num;
    private Boolean flag;
}

String url = "http://localhost:8080/get?num={id}&taskName={taskName}&flag={f}";
String result = restTemplate.getForObject(url, String.class,5,"我的任务",true);

@GetMapping(value = "/get")
public TaskDO get(TaskDO paramType) {
    return paramType;
}