SpringMVC的表单验证及错误处理

// Controller类中表单验证的示例
@RequestMapping(value="/register", method=RequestMethod.POST)
public String register(@Valid User user, BindingResult result) {
    if (result.hasErrors()) {
        return "registerForm";
    }
    // 注册逻辑...
    return "success";
}

// User类的验证规则示例
public class User {
    @NotBlank(message="用户名不能为空")
    private String username;
    
    @Size(min=6, max=20, message="密码长度需在6到20个字符之间")
    private String password;
    
    // 其他属性和getter/setter方法...
}

SpringMVC的数据绑定及类型转换

// Controller类中数据绑定及类型转换的示例
@RequestMapping(value="/submitForm", method=RequestMethod.POST)
public String submitForm(@ModelAttribute("form") FormData form) {
    // 表单提交逻辑...
    return "success";
}

// FormData类的属性绑定示例
public class FormData {
    private int id;
    private String name;
    private Date date;
    
    // 其他属性和getter/setter方法...
    
    // 需要自定义的类型转换器，将字符串转换为Date类型
    @DateTimeFormat(pattern="yyyy-MM-dd")
    public void setDate(Date date) {
        this.date = date;
    }
}

SpringMVC的RESTful API设计与实现

// Controller类中RESTful API的示例
@GetMapping("/users/{id}")
public ResponseEntity getUser(@PathVariable("id") int id) {
    User user = userService.getUserById(id);
    if (user != null) {
        return new ResponseEntity(user, HttpStatus.OK);
    } else {
        return new ResponseEntity<>(HttpStatus.NOT_FOUND);
    }
}

// UserService类的方法示例
public User getUserById(int id) {
    // 根据id查询用户逻辑...
    return user;
}