[BackEnd_Servers] REST API (GET/POST/PUT/DELETE)

HTTP METHODS

  - GET: 리소스 조회 

  - POST: 데이터의 처리 (등록 INSERT)

  - PUT: 리소스 대체(전체수정 UPDATE), 대체 리소스가 없을 시 생성(INSERT) 

  - PATCH: 리소스 "부분변경" (수정 UPDATE)

  - DELETE: 리소스 삭제   

 

---

 REST API Excesicse..

 

1.1. XML Response

REST API Code 

Spring REST API for HTTP GET method.

@RequestMapping(value = "/employees", produces = MediaType.APPLICATION_XML_VALUE, method = RequestMethod.GET) public String getAllEmployeesXML(Model model) {     model.addAttribute("employees", getEmployeesCollection());     return "xmlTemplate"; }

REST Client Code 

Spring REST client using RestTemplate to access HTTP GET api requests.

private static void getEmployees() {     final String uri = "http://localhost:8080/springrestexample/employees.xml";           RestTemplate restTemplate = new RestTemplate();     String result = restTemplate.getForObject(uri, String.class);           System.out.println(result); }

 

 

1.2. JSON Response

REST API Code

Spring REST API for HTTP GET method.

@RequestMapping(value = "/employees", produces = MediaType.APPLICATION_JSON_VALUE,  method = RequestMethod.GET) public String getAllEmployeesJSON(Model model) {     model.addAttribute("employees", getEmployeesCollection());     return "jsonTemplate"; }

REST Client Code

Spring REST client using RestTemplate to access HTTP GET api requests.

private static void getEmployees() {     final String uri = "http://localhost:8080/springrestexample/employees.json";           RestTemplate restTemplate = new RestTemplate();     String result = restTemplate.getForObject(uri, String.class);           System.out.println(result); }

 

 

1.3. Custom HTTP Headers with RestTemplate

REST API Code

@RequestMapping(value = "/employees", produces = MediaType.APPLICATION_JSON_VALUE,  method = RequestMethod.GET) public String getAllEmployeesJSON(Model model) {     model.addAttribute("employees", getEmployeesCollection());     return "jsonTemplate"; }

REST Client Code

private static void getEmployees() {     final String uri = "http://localhost:8080/springrestexample/employees";           RestTemplate restTemplate = new RestTemplate();           HttpHeaders headers = new HttpHeaders();     headers.setAccept(Arrays.asList(MediaType.APPLICATION_JSON));     HttpEntity<String> entity = new HttpEntity<String>("parameters", headers);           ResponseEntity<String> result = restTemplate.exchange(uri, HttpMethod.GET, entity, String.class);           System.out.println(result); }

 

 

1.4. Get Response as Object

REST API Code

@RequestMapping(value = "/employees", produces = MediaType.APPLICATION_XML_VALUE, method = RequestMethod.GET) public String getAllEmployeesXML(Model model) {     model.addAttribute("employees", getEmployeesCollection());     return "xmlTemplate"; }

REST Client Code

private static void getEmployees() {     final String uri = "http://localhost:8080/springrestexample/employees";     RestTemplate restTemplate = new RestTemplate();           EmployeeListVO result = restTemplate.getForObject(uri, EmployeeListVO.class);           System.out.println(result); }

 

 

1.5. URL Parameters

REST API Code

@RequestMapping(value = "/employees/{id}") public ResponseEntity<EmployeeVO> getEmployeeById (@PathVariable("id") int id) {     if (id <= 3) {         EmployeeVO employee = new EmployeeVO(1,"Ukjae","Jung","test@email.com");         return new ResponseEntity<EmployeeVO>(employee, HttpStatus.OK);     }     return new ResponseEntity(HttpStatus.NOT_FOUND); }

REST Client Code

private static void getEmployeeById() {     final String uri = "http://localhost:8080/springrestexample/employees/{id}";           Map<String, String> params = new HashMap<String, String>();     params.put("id", "1");           RestTemplate restTemplate = new RestTemplate();     EmployeeVO result = restTemplate.getForObject(uri, EmployeeVO.class, params);           System.out.println(result); }

 

 

2. Spring RestTemplate – HTTP POST Method Example

REST API Code

Spring REST API for HTTP POST method.

@RequestMapping(value = "/employees", method = RequestMethod.POST) public ResponseEntity<String> createEmployee(@RequestBody EmployeeVO employee) {     System.out.println(employee);     return new ResponseEntity(HttpStatus.CREATED); }

REST Client Code

Spring REST client using RestTemplate to access HTTP POST api requests.

private static void createEmployee() {     final String uri = "http://localhost:8080/springrestexample/employees";       EmployeeVO newEmployee = new EmployeeVO(-1, "Ukjae", "Jung", "test@email.com");       RestTemplate restTemplate = new RestTemplate();     EmployeeVO result = restTemplate.postForObject( uri, newEmployee, EmployeeVO.class);       System.out.println(result); }

 

 

3. Spring RestTemplate – HTTP PUT Method Example

REST API Code

Spring REST API for HTTP PUT method.

@RequestMapping(value = "/employees/{id}", method = RequestMethod.PUT) public ResponseEntity<EmployeeVO> updateEmployee(@PathVariable("id") int id, @RequestBody EmployeeVO employee) {     System.out.println(id);     System.out.println(employee);     return new ResponseEntity<EmployeeVO>(employee, HttpStatus.OK); }

REST Client Code

Spring REST client using RestTemplate to access HTTP PUT api requests.

private static void updateEmployee() {     final String uri = "http://localhost:8080/springrestexample/employees/{id}";           Map<String, String> params = new HashMap<String, String>();     params.put("id", "2");           EmployeeVO updatedEmployee = new EmployeeVO(2, "New Name", "Ukjae", "test@email.com");           RestTemplate restTemplate = new RestTemplate();     restTemplate.put ( uri, updatedEmployee, params); }

 

 

4. Spring RestTemplate – HTTP DELETE Method Example

REST API Code

Spring REST API for HTTP DELETE method.

@RequestMapping(value = "/employees/{id}", method = RequestMethod.DELETE) public ResponseEntity<String> updateEmployee(@PathVariable("id") int id) {     System.out.println(id);     return new ResponseEntity(HttpStatus.OK); }

REST Client Code

Spring REST client using RestTemplate to access HTTP DELETE api requests.

private static void deleteEmployee() {     final String uri = "http://localhost:8080/springrestexample/employees/{id}";           Map<String, String> params = new HashMap<String, String>();     params.put("id", "2");           RestTemplate restTemplate = new RestTemplate();     restTemplate.delete ( uri,  params ); }

 

 

 

 

exit..