@ModelAttribute 注解（8）
- 2020 年 3 月 17 日
- 筆記
@ModelAttribute 注释方法
@Controller @RequestMapping("/springmvc") public class TestController { /** * 运行流程：@ModelAttribute注释的方法会在此controller每个方法执行前被执行 * 1. 执行 @ModelAttribute 修饰的方法：模拟数据库取出行为，将user对象存储到map中，键为 user * 2. 然后在渲染页面时，模拟回显数据，将model中的数据取出并显示在页面，并把表单的请求参数赋给User对象的对应属性 * 3. sprinngMVC 最后把上述对象传入目标方法的参数 * 要注意的是：在存入map时，map的键值要和被@RequestMapping("/testModelAttribute")修饰的目标方法入参类型的第一个字符串的字符串一致 * @param user * @return */ @RequestMapping("/testModelAttribute") public String testModelAttribute01(User user){ System.out.println("修改： " + user); return "success"; } /** * @ModelAttribute 标记的方法，会在每个目标方法执行之前被SpringMVC调用 * @param id * @param map */ @ModelAttribute public void testModelAttribute(@RequestParam(value = "id",required = false) Integer id,Map<String,Object> map){ if(id != null){ // 模拟从数据库中获取对象 User user = new User(1,"Tom","123456","[email protected]",12); System.out.println("从数据库中获取一个对象：" + user); map.put("user",user); } } }
public class User { private Integer id; private String username; private String password; private String email; private int age; private Address address; public void setUsername(String username) { this.username = username; } public String getUsername() { return username; } public void setPassword(String password) { this.password = password; } public String getPassword() { return password; } public void setEmail(String email) { this.email = email; } public String getEmail() { return email; } public void setAge(int age) { this.age = age; } public int getAge() { return age; } public void setAddress(Address address) { this.address = address; } public Address getAddress() { return address; } public void setId(Integer id) { this.id = id; } public Integer getId() { return id; } @Override public String toString() { return "User{" + "id=" + id + ", username='" + username + ''' + ", password='" + password + ''' + ", email='" + email + ''' + ", age=" + age + '}'; } public User(Integer id,String username, String password, String email, int age){ super(); this.username = username; this.password = password; this.email = email; this.age = age; this.id = id; } public User(){} }
<!-- 模拟修改操作 1. 原始数据：1，Tom，[email protected]，12 2. 密码不能被修改 3. 表单回显，模拟操作直接填写对应的属性值 --> <form action="/springmvc/testModelAttribute" method="post"> <input type="hidden" name="id" value="1"> username:<input type="text" name="username" value="Tom"> email:<input type="text" name="email" value="[email protected]"> age:<input type="text" name="age" value="12"> <input type="submit" name="Submit"> </form>
@ModelAttribute 注释参数
@ModelAttribute("user") User user注释方法参数，参数user的值来源于testModelAttribute03()方法中的model属性。
@ModelAttribute("user") public User testModelAttribute03(){ return new User(1,"aa","123","[email protected]",12); } @RequestMapping("/testModelAttribute01") public String testModelAttribute04(@ModelAttribute("user") User user){ user.setUsername("bb"); return "success"; }
