Resttemplate

2019, Jan 17    

Spring Boot中http请求的发送与接收

1.get请求

  1. get发送请求格式：http://localhost:8080/test?name=Tom&age=13 
    // 方式一
String uri = "http://localhost:8080/test?name={name}&age={age}";
Map<String, Object> params = new HashMap<String, Object>();
params.put("name", "Tom");
params.put("age", "13");
RestTemplate restTemplate = new RestTemplate();
ResponseEntity<String> result = restTemplate.getForEntity(uri, String.class, params); // 方式一返回内容：<200,result,{Content-Type=[text/plain;charset=UTF-8], Content-Length=[6], Date=[Tue, 24 Jul 2018 11:59:04 GMT]}>
// 可以通过一下方式获取result的不同字段的值
result.getStatusCode() // 200
result.getBody() // result
result.getHeaders() // {Content-Type=[text/plain;charset=UTF-8], Content-Length=[6], Date=[Tue, 24 Jul 2018 11:59:04 GMT]}
   
// 方式二
String uri = "http://localhost:8080/test?name={name}&age={age}";
Map<String, Object> params = new HashMap<String, Object>();
params.put("name", "Tom");
params.put("age", "13");
RestTemplate restTemplate = new RestTemplate();
String result = restTemplate.getForObject(uri, String.class, params); // 方式二返回内容：result
   
   
注意：参数除了可以放在map中，还可以依次放在第三个参数的位置，如下所示
restTemplate.getForObject("http://admin-service/dpmt?workNumber={workNumber}", String.class, workNumber);
restTemplate.getForObject("http://admin-service/dpmt?workNumber={workNumber}&name={name}", String.class, workNumber, name);

    接收请求代码

    // 方式一
@RequestMapping(value="/test", method=RequestMethod.GET)
@ResponseBody
public String testGet(String name, String age) {
	String result = "result";
	logger.info("name:{} age:{}", name, age);
	return result;
}
   
// 方式二
@RequestMapping(value="/test", method=RequestMethod.GET)
@ResponseBody
public String testGet(HttpServletRequest request) {
	String result = "result";
	String name = request.getParameter("name");
	String age = request.getParameter("age");
	logger.info("name:{} age:{}", name, age);
	return result;
}
   
// 方式三
@RequestMapping(value="/test", method=RequestMethod.GET)
@ResponseBody
public String testGet(Person person) { // 建立一个带有name和age属性的Persion类
	String result = "result";
	String name = person.getName();
	String age = person.getAge();
	logger.info("name:{} age:{}", name, age);
	return result;
}
   
// 方式四
@RequestMapping(value="/test", method=RequestMethod.GET)
@ResponseBody
public String testGet(@RequestParam("name") String name, @RequestParam("age") String age) {
	String result = "result";
	logger.info("name:{} age:{}", name, age);
	return result;
}

  2. get发送请求格式http://localhost:8080/test/Tom

    // 发送方式就是上面的两种，本质都一样，举一个例子说明
String uri = "http://localhost:8080/test/{name}";
Map<String, Object> params = new HashMap<String, Object>();
params.put("name", "Tom");
RestTemplate restTemplate = new RestTemplate();
String result = restTemplate.getForObject(uri, String.class, params);

    接收请求代码

    @RequestMapping(value="/test/{name}", method=RequestMethod.GET)
@ResponseBody
public String testGet(@PathVariable("name") String name) {
	String result = "result";
	logger.info("name:{}", name);
	return result;
}

2.post请求

  1. post发送请求格式：http://localhost:8080/testPost/Tom?age=13&height=170

    String uri = "http://localhost:8080/testPost/{name}?age={age}&height={height}";
RestTemplate restTemplate = new RestTemplate();
Map<String, Object> params = new HashMap<String, Object>();
params.put("name", "Tom");
params.put("age", "13");
params.put("height", "170");
String request = "this is request body";
ResponseEntity<String> result = restTemplate.postForEntity(uri, request, String.class, params);

    接收请求代码

    @RequestMapping(value = "/testPost/{name}", method = RequestMethod.POST)
@ResponseBody
public String testPost(@RequestBody (required=false) String requestBody, @PathVariable("name") String name, @RequestParam("age") String age,String height) {
	String result = "result";
	logger.info("requestBody:{}", requestBody);
	logger.info("name:{}", name);
	logger.info("age:{}", age);
	return result;
}

  2. post发送请求格式：http://localhost:8080/testPost/Tom (参数在请求体中)

    String uri = "http://localhost:8080/testPost";
RestTemplate restTemplate = new RestTemplate();
String request = "this is request body";
ResponseEntity<String> result = restTemplate.postForEntity(uri, request, String.class);

    接收请求代码

    @RequestMapping(value = "/testPost", method = RequestMethod.POST)
@ResponseBody
public String testPost(@RequestBody (required=false) String requestBody) {
	String result = "result";
	logger.info("requestBody:{}", requestBody);
	return result;
}

    2.注意

    1.uriVariables’ must not be null，如果没有任何参数，官方函数放参数位置的形参不能直接写null，正确的写法是创建一个不含任何参数的HashMap或不含任何属性的Object对象。

    String result = restTemplate.getForObject("http://localhost:9999/get", String.class, new HashMap());

    3.delete等请求

    这些请求推荐使用exchange函数

    实例代码

    public  void  deleteQueue(String vhost,String queue){
        HttpHeaders headers = new HttpHeaders();//header参数
        headers.add("authorization",Auth);
        headers.setContentType(MediaType.APPLICATION_JSON);
   
        JSONObject content = new JSONObject();//放入body中的json参数
        content.put("mode","delete");
        content.put("name",queue);
        content.put("vhost","/" + vhost);
   
        String newUrl = url;
   
        HttpEntity<JSONObject> request = new HttpEntity<>(content,headers); //组装请求体和请求头
     
        ResponseEntity<String> response = template.exchange(newUrl,HttpMethod.DELETE,request,String.class);
    }
   
/*
 * 如果参数都在url上（没有requestBody）
 */
restTemplate.exchange(url, HttpMethod.DELETE,null, JSONObject.class); // HttpEntity参数可以置空

    如果出现org.springframework.web.client.HttpClientErrorException: 400 null

    检查url是否拼接有问题，这回导致请求不符合服务端要求

# REST、RESTful