概述

• TestRestTemplate 是用于 Restful 請求的模版,并支持異步調用，默認情況下 RestTemplate 依靠 JDK 工具來建立 HTTP 鏈接，你也可以通過 setRequestFactory 方法來切換不同的 HTTP 庫，如 Apache 的 HttpComponents 或 Netty 和 OkHttp
• 通常在入口類或配置類將其注入到IOC容器，它有兩個構造方法

默認初始化

@Bean
public RestTemplate restTemplate(){
    return new RestTemplate();
}

構造方法中可以傳入ClientHttpRequestFactory參數,ClientHttpRequestFactory接口的實現類中存在timeout屬性等等

@Bean
RestTemplate restTemplate(){
    SimpleClientHttpRequestFactory requestFactory = new          SimpleClientHttpRequestFactory();
    requestFactory.setConnectTimeout(1000);
    requestFactory.setReadTimeout(1000);

    RestTemplate restTemplate = new RestTemplate(requestFactory);
    return restTemplate;
}

• 它主要提供了了以下方法，對應不同的 HTTP 請求

GET請求測試

@Test
    public void get() throws Exception {
        Map<String,String> multiValueMap = new HashMap<>();
        multiValueMap.put("username","lake");//傳值，但要在url上配置相應的參數
        ActResult result = testRestTemplate.getForObject("/test/get?username={username}",ActResult.class,multiValueMap);
        Assert.assertEquals(result.getCode(),0);
    }

POST請求測試

@Test
    public void post() throws Exception {
        MultiValueMap multiValueMap = new LinkedMultiValueMap();
        multiValueMap.add("username","lake");
        ActResult result = testRestTemplate.postForObject("/test/post",multiValueMap,ActResult.class);
        Assert.assertEquals(result.getCode(),0);
    }

文件上傳測試

 @Test
    public void upload() throws Exception {
        Resource resource = new FileSystemResource("/home/lake/github/wopi/build.gradle");
        MultiValueMap multiValueMap = new LinkedMultiValueMap();
        multiValueMap.add("username","lake");
        multiValueMap.add("files",resource);
        ActResult result = testRestTemplate.postForObject("/test/upload",multiValueMap,ActResult.class);
        Assert.assertEquals(result.getCode(),0);
    }

文件下載測試

 @Test
    public void download() throws Exception {
        HttpHeaders headers = new HttpHeaders();
        headers.set("token","xxxxxx");
        HttpEntity formEntity = new HttpEntity(headers);
        String[] urlVariables = new String[]{"admin"};
        ResponseEntity<byte[]> response = testRestTemplate.exchange("/test/download?username={1}",HttpMethod.GET,formEntity,byte[].class,urlVariables);
        if (response.getStatusCode() == HttpStatus.OK) {
            Files.write(response.getBody(),new File("/home/lake/github/file/test.gradle"));
        }
    }

請求頭信息測試

@Test
    public void getHeader() throws Exception {
        HttpHeaders headers = new HttpHeaders();
        headers.set("token","xxxxxx");
        HttpEntity formEntity = new HttpEntity(headers);
        String[] urlVariables = new String[]{"admin"};
        ResponseEntity<ActResult> result = testRestTemplate.exchange("/test/getHeader?username={username}", HttpMethod.GET,formEntity,ActResult.class,urlVariables);
        Assert.assertEquals(result.getBody().getCode(),0);
    }

PUT請求測試

 @Test
    public void putHeader() throws Exception {
        HttpHeaders headers = new HttpHeaders();
        headers.set("token","xxxxxx");
        MultiValueMap multiValueMap = new LinkedMultiValueMap();
        multiValueMap.add("username","lake");
        HttpEntity formEntity = new HttpEntity(multiValueMap,headers);
        ResponseEntity<ActResult> result = testRestTemplate.exchange("/test/putHeader", HttpMethod.PUT,formEntity,ActResult.class);
        Assert.assertEquals(result.getBody().getCode(),0);
    }

• DELETE請求測試

@Test
    public void delete() throws Exception {
        HttpHeaders headers = new HttpHeaders();
        headers.set("token","xxxxx");
        MultiValueMap multiValueMap = new LinkedMultiValueMap();
        multiValueMap.add("username","lake");
        HttpEntity formEntity = new HttpEntity(multiValueMap,headers);
        String[] urlVariables = new String[]{"admin"};
        ResponseEntity<ActResult> result = testRestTemplate.exchange("/test/delete?username={username}", HttpMethod.DELETE,formEntity,ActResult.class,urlVariables);
        Assert.assertEquals(result.getBody().getCode(),0);
    }

異步請求

- 異步調用要使用AsyncRestTemplate。 它是RestTemplate的擴展，提供了異步http請求處理的一種機制，通過返回ListenableFuture對象生成回調機制，以達到異步非阻塞發送http請求

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";  
}