SpringMVC中的一些注解

@Controller：表明该类是一个Controller；

@RequestMapping(参数) ：为类或者方法定义一个url

@RequestParam(value = "id"  )：获取请求中的参数

package com.hongcong.controller;

import java.util.ArrayList;
import java.util.List;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.servlet.ModelAndView;

import com.hongcong.model.StudentModel;

@Controller
//访问这个controller时，需要在url中加入/student
@RequestMapping("/student")
public class StudentController {
    
    private static List<StudentModel> studentList = new ArrayList<StudentModel>();
     private int id =3;
    static{
        studentList.add(new StudentModel(1,"张三",11));
        studentList.add(new StudentModel(2,"李六",13));
        studentList.add(new StudentModel(3,"王五",14));
    }
    
　　//访问这个方法时，url为../student/studentList
    @RequestMapping("/studentList")
    public ModelAndView studentList(){
　　　　 //ModelAndView的作用是传递参数和页面跳转
        ModelAndView mav = new ModelAndView();
　　　　 //跳转到student目录下的studentList.jsp页面  注：lib目录下的页面无法直接访问
        mav.setViewName("student/studentList");
　　　　 //传递参数 页面可以通过jstl表达式等方法获取参数
        mav.addObject("studentList", studentList);
        return mav;
    }
    
    @RequestMapping("/preSave")
　　 //@RequestParam(value = "otype",required = false) String otype 是获取请求中的参数并且赋值给otype这个变量，其中参数required = true时，那这个请求必须要有otype参数，不然会报错
    public ModelAndView preSave(@RequestParam(value = "id"  ) int id,
            @RequestParam(value = "otype",required = false) String otype){
        ModelAndView mav = new ModelAndView();        
        StudentModel studentModel = new StudentModel();
        if("update".equals(otype)){
            for (StudentModel model : studentList) {
                if(model.getId() == id){
                    studentModel = model;
                    break;
                }
            }
        }
        mav.addObject("studentModel", studentModel);
        mav.setViewName("student/StudentUpdate");        
        return mav;
    }
    
    @RequestMapping("/Save")
    public String Save(StudentModel studentModel){
        if(studentModel.getId() == 0){
            this.id++;
            studentModel.setId(this.id);
        }else{
            for (StudentModel model : studentList) {
                if(id == model.getId()){
                    studentList.remove(model);
                    break;
                }
            }
            studentModel.setId(id);
        }
        studentList.add(studentModel);
　　　　 //重定向
        return "redirect:/student/studentList.do";
    }
}