注销以及跳转的神奇以及restful风格

注销登录

1.	退出（session失效）
    登录之后放到session中的
	session.invalidate();
2. ssion移除某一个属性
	session.removeAttribute("user");

跳转
前端

编辑
添加员工

controller

@GetMapping("/emp")
    public String toAddPage(Model model) {
        Collection departments = departmentDao.getDepartments();
        model.addAttribute("departments", departments);
        return "emp/add";
    }

    @PostMapping("/emp")
    public String AddEmp(Employee employee) {
        System.out.println(employee);
        employeeDao.add(employee);
        return "redirect:/emps";
    }

    //去修改页面
    @GetMapping("/emp/{id}")
    public String toUpdateEmp(@PathVariable("id") Integer id, Model model) {
        Employee employee = employeeDao.getEmployee(id);
        model.addAttribute("emp", employee);
        Collection departments = departmentDao.getDepartments();
        model.addAttribute("departments", departments);
        return "emp/update";
    }

三个都是emp跳转，区分一个是post请求，一个是get请求，一个是restful风格都不冲突，真的好神奇呀

    @RequestMapping("/updateBook")
    public String updateBook(Books books) {
        System.out.println("updateBook=>"+books);
        bookService.updateBook(books);
        return "redirect:/book/allBook";
    }

    @RequestMapping("/deleteBook/{bookId}")
    public String deleteBook(@PathVariable("bookId") int id) {
    bookService.deleteBookById(id);
        return "redirect:/book/allBook";
    }

restful风格可以在controller写@RequestMapping("/deleteBook/{bookId}") public String deleteBook(@PathVariable("bookId") int id)