REST中处理异常的最简单方法
在rest中,其实如果要抛出异常或者给出出錯信息,返回的相关的HTTP 状态码,最简单的
方法就是使用ResponseEntity,马上看例子:
@Controllerpublic class EmpController { List<Employee> list = new ArrayList<Employee>(); //Steps followed in this code are: //1) Validate the input //2) Do processing //3) Return appropriate HTTP code and message. @RequestMapping(value = "/getEmp/{emp}", method = RequestMethod.GET) public ResponseEntity<?> getEmployee(@PathVariable("emp") int empid) { if(empid < 0) { return new ResponseEntity<String>("Employee Id is not valid.", HttpStatus.BAD_REQUEST); } for (Iterator<Employee> iterator = list.iterator(); iterator.hasNext();) { Employee emp = (Employee) iterator.next(); if(emp.getEmpId()==empid) { return new ResponseEntity<Employee>(emp,HttpStatus.OK); } } return new ResponseEntity<String>("Employee with id: " + empid + " not found.", HttpStatus.NOT_FOUND); } @RequestMapping(value = "/removeEmp/{emp}", method = RequestMethod.DELETE) public ResponseEntity<?> removeEmployee(@PathVariable("emp") int empid) { if(empid < 0) { return new ResponseEntity<String>("Employee Id is not valid.", HttpStatus.BAD_REQUEST); } for (Iterator<Employee> iterator = list.iterator(); iterator.hasNext();) { Employee emp = (Employee) iterator.next(); if(emp.getEmpId()==empid) { iterator.remove(); return new ResponseEntity<String>("Employee Successfully removed.", HttpStatus.OK); } } return new ResponseEntity<String>("Employee Not found.", HttpStatus.NOT_FOUND); } @RequestMapping(value = "/addEmp", method = RequestMethod.POST) public ResponseEntity<?> addEmployee(@RequestBody Employee emp) { if(emp.getEmpId() < 0) { return new ResponseEntity<String>("Employee Id is not valid.", HttpStatus.BAD_REQUEST); } if(StringUtils.isBlank(emp.getDeptName())) { return new ResponseEntity<String>("Department name is not valid.", HttpStatus.BAD_REQUEST); } for (Iterator<Employee> iterator = list.iterator(); iterator.hasNext();) { Employee tempEmp = (Employee) iterator.next(); if(tempEmp.getEmpId()==emp.getEmpId()) { return new ResponseEntity<String>("Employee already present. No need to add again", HttpStatus.OK); } } list.add(emp); return new ResponseEntity<String>("Employee Successfully Added", HttpStatus.OK); } @RequestMapping(value = "/updateEmp", method = RequestMethod.PUT) public ResponseEntity<?> updateEmployee(@RequestBody Employee emp) { if(emp.getEmpId() < 0) { return new ResponseEntity<String>("Employee Id is not valid.", HttpStatus.BAD_REQUEST); } if(StringUtils.isBlank(emp.getDeptName())) { return new ResponseEntity<String>("Department name is not valid.", HttpStatus.BAD_REQUEST); } for (Iterator<Employee> iterator = list.iterator(); iterator.hasNext();) { Employee tempEmp = (Employee) iterator.next(); if(tempEmp.getEmpId()==emp.getEmpId()) { tempEmp.setDeptName(emp.getDeptName()); return new ResponseEntity<String>("Employee Successfully updated", HttpStatus.OK); } } return new ResponseEntity<String>("Employee Not found.", HttpStatus.NOT_FOUND); } @ExceptionHandler public ResponseEntity<String> exceptionHandler(Exception e){ e.printStackTrace(); return new ResponseEntity<String>("An internal error occurred while processing your request.", HttpStatus.INTERNAL_SERVER_ERROR); }}