springboot-24-restTemplate的使用

项目中使用的是HttpClient, 后来改成springboot, 偶然间发现restTemplate

{
  "Author": "tomcat and jerry",
  "url":"http://www.cnblogs.com/tomcatandjerry/p/5899722.html"
} 

核心代码:

String url = "http://localhost:8080/json";
JSONObject json = restTemplate.getForEntity(url, JSONObject.class).getBody();  

实用:

restConfig.java

package com.iwhere.scrapy.rest;

import java.nio.charset.Charset;
import java.util.Iterator;
import java.util.List;

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.SimpleClientHttpRequestFactory;
import org.springframework.http.converter.HttpMessageConverter;
import org.springframework.http.converter.StringHttpMessageConverter;
import org.springframework.web.client.RestOperations;
import org.springframework.web.client.RestTemplate;

/**
 * 定义restTemplate的配置
 *
 * @author wenbronk
 * @Date 下午4:33:35
 */
@Configuration
public class RestTemplateConfig {

    @Bean
    @ConditionalOnMissingBean({ RestOperations.class, RestTemplate.class })
    public RestTemplate restTemplate(ClientHttpRequestFactory factory) {
        // return new RestTemplate(factory);

        RestTemplate restTemplate = new RestTemplate(factory);

        // 使用 utf-8 编码集的 conver 替换默认的 conver（默认的 string conver 的编码集为"ISO-8859-1"）
        List<HttpMessageConverter<?>> messageConverters = restTemplate.getMessageConverters();
        Iterator<HttpMessageConverter<?>> iterator = messageConverters.iterator();
        while (iterator.hasNext()) {
            HttpMessageConverter<?> converter = iterator.next();
            if (converter instanceof StringHttpMessageConverter) {
                iterator.remove();
            }
        }
        messageConverters.add(new StringHttpMessageConverter(Charset.forName("UTF-8")));

        return restTemplate;
    }

    @Bean
    @ConditionalOnMissingBean({ClientHttpRequestFactory.class})
    public ClientHttpRequestFactory simpleClientHttpRequestFactory() {
        SimpleClientHttpRequestFactory factory = new SimpleClientHttpRequestFactory();
        factory.setReadTimeout(15000);// ms
        factory.setConnectTimeout(15000);// ms
        return factory;
    }
}

请求测试:

SpringRestTemplateApp.java
@RestController
@EnableAutoConfiguration
@Import(value = {Conf.class})
public class SpringRestTemplateApp {  

    @Autowired
    RestTemplate restTemplate;  

    /***********HTTP GET method*************/
    @RequestMapping("")
    public String hello(){
        String url = "http://localhost:8080/json";
        JSONObject json = restTemplate.getForEntity(url, JSONObject.class).getBody();
        return json.toJSONString();
    }  

    @RequestMapping("/json")
    public Object genJson(){
        JSONObject json = new JSONObject();
        json.put("descp", "this is spring rest template sample");
        return json;
    }  

    /**********HTTP POST method**************/
    @RequestMapping("/postApi")
    public Object iAmPostApi(@RequestBody JSONObject parm){
        System.out.println(parm.toJSONString());
        parm.put("result", "hello post");
        return parm;
    }  

    @RequestMapping("/post")
    public Object testPost(){
        String url = "http://localhost:8080/postApi";
        JSONObject postData = new JSONObject();
        postData.put("descp", "request for post");
        JSONObject json = restTemplate.postForEntity(url, postData, JSONObject.class).getBody();
        return json.toJSONString();
    }  

    public static void main(String[] args) throws Exception {
        SpringApplication.run(SpringRestTemplateApp.class, args);
    }  

}

也可以异步调用

@RequestMapping("/async")
    public String asyncReq(){
        String url = "http://localhost:8080/jsonAsync";
        ListenableFuture<ResponseEntity<JSONObject>> future = asyncRestTemplate.getForEntity(url, JSONObject.class);
        future.addCallback(new SuccessCallback<ResponseEntity<JSONObject>>() {
            public void onSuccess(ResponseEntity<JSONObject> result) {
                System.out.println(result.getBody().toJSONString());
            }
        }, new FailureCallback() {
            public void onFailure(Throwable ex) {
                System.out.println("onFailure:"+ex);
            }
        });
        return "this is async sample";

自定义header

@RequestMapping("/headerApi")//模拟远程的restful API
    public JSONObject withHeader(@RequestBody JSONObject parm, HttpServletRequest req){
        System.out.println("headerApi====="+parm.toJSONString());
        Enumeration<String> headers = req.getHeaderNames();
        JSONObject result = new JSONObject();
        while(headers.hasMoreElements()){
            String name = headers.nextElement();
            System.out.println("["+name+"]="+req.getHeader(name));
            result.put(name, req.getHeader(name));
        }
        result.put("descp", "this is from header");
        return result;
    }  

    @RequestMapping("/header")
    public Object postWithHeader(){
　　　　//该方法通过restTemplate请求远程restfulAPI
        HttpHeaders headers = new HttpHeaders();
        headers.set("auth_token", "asdfgh");
        headers.set("Other-Header", "othervalue");
        headers.setContentType(MediaType.APPLICATION_JSON);  

        JSONObject parm = new JSONObject();
        parm.put("parm", "1234");
        HttpEntity<JSONObject> entity = new HttpEntity<JSONObject>(parm, headers);
        HttpEntity<String> response = restTemplate.exchange(
                "http://localhost:8080/headerApi", HttpMethod.POST, entity, String.class);//这里放JSONObject, String 都可以。因为JSONObject返回的时候其实也就是string
        return response.getBody();
    }