Springboot 使用RestTemplate

超、凢脫俗 2022-12-22 09:21 553阅读 0赞

**最近项目中springboot使用了RestTemplate，在此了解和学习了一下，有问题请指正**

## 创建RestTemplate  ##

//自创建RestTemplate 
    public static RestTemplate restTemplate() {
            SimpleClientHttpRequestFactory requestFactory = new SimpleClientHttpRequestFactory();
            requestFactory.setConnectTimeout(30000);// 设置连接超时，单位毫秒
            requestFactory.setReadTimeout(30000);  //设置读取超时
            RestTemplate restTemplate = new RestTemplate();
            restTemplate.setRequestFactory(requestFactory);
            logger.info("RestTemplate初始化完成");
            return restTemplate;
        }
    
    
    
    //使用注解注入
    @Autowired
    private  RestTemplate restTemplate;

引用的是spring-web-4.3.6.RELEASE.jar

## 设置请求头HttpHeaders ##

请求头中常设置的参数是Content-Type，一般用setContentType(MediaType mediaType)方式添加MediaType类中存在的值，或者用add(name，value)的方式添加所需要的值

MediaType类关于具体值的源码如下：

public static final MediaType ALL = valueOf("*/*");
        public static final String ALL_VALUE = "*/*";
        public static final MediaType APPLICATION_ATOM_XML = valueOf("application/atom+xml");
        public static final String APPLICATION_ATOM_XML_VALUE = "application/atom+xml";
        public static final MediaType APPLICATION_FORM_URLENCODED = valueOf("application/x-www-form-urlencoded");
        public static final String APPLICATION_FORM_URLENCODED_VALUE = "application/x-www-form-urlencoded";
        public static final MediaType APPLICATION_JSON = valueOf("application/json");
        public static final String APPLICATION_JSON_VALUE = "application/json";
        public static final MediaType APPLICATION_JSON_UTF8 = valueOf("application/json;charset=UTF-8");
        public static final String APPLICATION_JSON_UTF8_VALUE = "application/json;charset=UTF-8";
        public static final MediaType APPLICATION_OCTET_STREAM = valueOf("application/octet-stream");
        public static final String APPLICATION_OCTET_STREAM_VALUE = "application/octet-stream";
        public static final MediaType APPLICATION_PDF = valueOf("application/pdf");
        public static final String APPLICATION_PDF_VALUE = "application/pdf";
        public static final MediaType APPLICATION_RSS_XML = valueOf("application/rss+xml");
        public static final String APPLICATION_RSS_XML_VALUE = "application/rss+xml";
        public static final MediaType APPLICATION_XHTML_XML = valueOf("application/xhtml+xml");
        public static final String APPLICATION_XHTML_XML_VALUE = "application/xhtml+xml";
        public static final MediaType APPLICATION_XML = valueOf("application/xml");
        public static final String APPLICATION_XML_VALUE = "application/xml";
        public static final MediaType IMAGE_GIF = valueOf("image/gif");
        public static final String IMAGE_GIF_VALUE = "image/gif";
        public static final MediaType IMAGE_JPEG = valueOf("image/jpeg");
        public static final String IMAGE_JPEG_VALUE = "image/jpeg";
        public static final MediaType IMAGE_PNG = valueOf("image/png");
        public static final String IMAGE_PNG_VALUE = "image/png";
        public static final MediaType MULTIPART_FORM_DATA = valueOf("multipart/form-data");
        public static final String MULTIPART_FORM_DATA_VALUE = "multipart/form-data";
        public static final MediaType TEXT_EVENT_STREAM = valueOf("text/event-stream");
        public static final String TEXT_EVENT_STREAM_VALUE = "text/event-stream";
        public static final MediaType TEXT_HTML = valueOf("text/html");
        public static final String TEXT_HTML_VALUE = "text/html";
        public static final MediaType TEXT_MARKDOWN = valueOf("text/markdown");
        public static final String TEXT_MARKDOWN_VALUE = "text/markdown";
        public static final MediaType TEXT_PLAIN = valueOf("text/plain");
        public static final String TEXT_PLAIN_VALUE = "text/plain";
        public static final MediaType TEXT_XML = valueOf("text/xml");
        public static final String TEXT_XML_VALUE = "text/xml";
        private static final String PARAM_QUALITY_FACTOR = "q";

**具体写法如下：**

HttpHeaders headers = new HttpHeaders();
    //相当于headers.add("Content-Type","application/json;charset=UTF-8");
    headers.setContentType(MediaType.APPLICATION_JSON_UTF8);
    或者添加MediaType类没有的值
    headers.add("Content-Type","application/x-www-form-urlencoded; charset=UTF-8");

## post请求 ##

### postForEntity ###

**如果请求参数是form-data类型的可以如下写法：**

String url = "http://127.0.0.1:8080/login";
    LinkedMultiValueMap<String, Object> paramMap = new LinkedMultiValueMap<>();
    paramMap.add("username", "zhangsan");
    paramMap.add("password", "123456");
    paramMap.add("randomStr",String.valueOf(System.currentTimeMillis()));
    HttpEntity<LinkedMultiValueMap<String, Object>> httpEntity = new HttpEntity<>(paramMap, requestHeaders);
    
    ResponseEntity<String> exchange = restTemplate.postForEntity(url, httpEntity, String.class);
    
    String resultRemote = exchange.getBody();//得到返回的值

**具体的请求参数和返回的参数样例如下：**

参数：

｛

username: 张三

password: 123456

randomStr: 1597300142432

｝

"code": 200,

"msg": "操作成功",

"data": \{

"token": "dfghjkl",

"username": "张三",

\},

"timestamp": 1597299860

**如果请求参数是json，而且里面还有json数组**

Map<String,Object> jsonMap = new HashMap<>();
    jsonMap.put("com","ty");
    Map<String,Object> deMap = new HashMap<>();
    deMap.put("name", "设备");
    List<Object> list = new ArrayList<>();
    list.add(deMap);
    jsonMap.put("des",list);
    logger.info("----"+JSONObject.toJSONString(jsonMap));
    
    HttpEntity<String>  httpEntitys = new HttpEntity<>(JSONObject.toJSONString(jsonMap),requestHeader);
    ResponseEntity<String> exchanges = restTemplate.postForEntity(url, httpEntitys, String.class);
    
    String resultRemote = exchanges.getBody();
    Map stringToMap = JSONObject.parseObject(resultRemote);

例子：

des": \[\{

"name": "设备"

\}\],

"com": "ty"

"code": 200,

"msg": "操作成功",

"data": "567897890-090",

"timestamp": 2367301740

## Get请求 ##

### getForEntity请求不带参数，默认请求头 ###

//请求不带参数，默认请求头
    String url = "xxx.xx.xx";
    ResponseEntity<String> result = restTemplate.getForEntity(url,String.class);

### getForEntity请求带参数 ###

//URL作为String
    String url = "http://127.0.0.1:8080/login?name={name}";
    Map<String,String> map = new HashMap<>();
    map.put("name","张三");
    ResponseEntity<String> result = restTemplate.getForEntity(url,String.class,map);
    
    //URL作为URI,参数存进URI中
    UriComponents uriComponents = UriComponentsBuilder.fromUriString(url).build().expand("李四").encode();
    URI uri = uriComponents.toUri();
    ResponseEntity<String> result = restTemplate.getForEntity(uri,String.class);
    
    
    //返回参数也可以是自定义对象例如User
    String url = "http://127.0.0.1:8080/login?name={name}";
    Map<String,String> map = new HashMap<>();
    map.put("name","张三");
    ResponseEntity<User> result = restTemplate.getForEntity(url,User.class,map);

### get请求带请求头 exchange ###

HttpHeaders resultRequestHeader = new HttpHeaders();
    resultRequestHeader.add("Authorization", "wetyuigyihjj");
    resultRequestHeader.add("charset", "UTF-8");
    resultRequestHeader.setContentType(MediaType.APPLICATION_JSON);
    LinkedMultiValueMap<String, Object> resultParamMap = new LinkedMultiValueMap<>();
    
    HttpEntity<String>  resultHttpEntity = new HttpEntity<>(null, resultRequestHeader);
    ResponseEntity<String> exchange = restTemplate.exchange(resultUrl, HttpMethod.GET,resultHttpEntity,String.class);
    
    resultRemote = exchange.getBody();
    logger.info("结果resultRemote:"+resultRemote);
    Map stringToMap = JSONObject.parseObject(resultRemote);

## PUT请求 ##

//put方法的参数和postForEntity方法的参数基本一致
    String url = "http://127.0.0.1:8080/login";
    Map<String,Object> jsonMap = new HashMap<>();
    jsonMap.put("username","admin");
    jsonMap.put("password","123456");
    HttpEntity<String>  httpEntitys = new HttpEntity<>(JSONObject.toJSONString(jsonMap),requestHeaders);
    
    restTemplate.put(url,httpEntitys,String.class);

### DELETE 请求 ###

String url = "http://127.0.0.1:8080/get?name={name}";
    restTemplate.delete(url,"张三");

## exchange方法 ##

### post请求 ###

String url = "http://127.0.0.1:8080/login";
    LinkedMultiValueMap<String, Object> paramMap = new LinkedMultiValueMap<>();
    paramMap.add("username", "zhangsan");
    paramMap.add("password", "123456");
    paramMap.add("randomStr",String.valueOf(System.currentTimeMillis()));
    HttpEntity<LinkedMultiValueMap<String, Object>> httpEntity = new HttpEntity<>(paramMap, requestHeaders);
    
    ResponseEntity<String> result = restTemplate.exchange(url, HttpMethod.POST,httpEntitys,String.class);
    
    String resultRemote = exchange.getBody();//得到返回的值

### get请求 ###

ResponseEntity<String> exchange = restTemplate.exchange(resultUrl, HttpMethod.GET,resultHttpEntity,String.class);
    
    或者
    
    ResponseEntity<String> exchange = restTemplate.exchange(url, HttpMethod.GET,null,String.class);

### put请求 ###

String url = "http://127.0.0.1:8080/login";
    LinkedMultiValueMap<String, Object> paramMap = new LinkedMultiValueMap<>();
    paramMap.add("username", "zhangsan");
    paramMap.add("password", "123456");
    paramMap.add("randomStr",String.valueOf(System.currentTimeMillis()));
    HttpEntity<LinkedMultiValueMap<String, Object>> httpEntity = new HttpEntity<>(paramMap, requestHeaders);
    
    ResponseEntity<String> result = restTemplate.exchange(url, HttpMethod.PUT,httpEntitys,String.class);

### delete请求 ###

String url = "http://127.0.0.1:8080/get";
    ResponseEntity<String> result = restTemplate.exchange(url + "?id={id}", HttpMethod.DELETE, null, String.class, 56789);