SpringMVC框架REST架构体系原理分析

package Mycontroller;
import entity.Student;
import entity.User;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.*;
import repository.StudentRepository;
import javax.servlet.http.HttpServletResponse;
import java.util.Collection;
@RequestMapping("/rest")
@RestController
public class RestHandler {
    @Autowired
    private StudentRepository studentRepository;
    @RequestMapping(value = "/findAll",method = RequestMethod.GET)
//    @GetMapping("/findAll")
    public Collection<Student> findAll(HttpServletResponse response){
        response.setContentType("text/json;charset=UTF-8");
        return studentRepository.findAll();
    }
    @GetMapping("/findById/{id}")
    public Student findById(@PathVariable("id") long id)
    {
        return studentRepository.findById(id);
    }
    @PostMapping("/sava")
    public void save(@RequestBody Student student){
        studentRepository.saveOrUpdate(student);
    }
    @PutMapping("/update")
    public void update(@RequestBody Student student){
        studentRepository.saveOrUpdate(student);
    }
    @DeleteMapping("/deleteById/{id}")
    public void deleteById(@PathVariable("id") long id){
        studentRepository.deleteById(id);
    }
}

@Repository
public class StudentRepositoryImpl implements StudentRepository {
    private static Map<Long, Student> studentMap;
    static {
        studentMap=new HashMap<>();
        studentMap.put(1L,new Student (1L,"zhangsan",22));
    }
    @Override
    public Collection<Student> findAll() {
        return studentMap.values();
    }
    @Override
    public Student findById(long id) {
        return studentMap.get(id);
    }
    @Override
    public void saveOrUpdate(Student student) {
        studentMap.put(student.getId(),student);
    }
    @Override
    public void deleteById(long id) {
        studentMap.remove(id);
    }
}