spring mvc controller中的参数验证机制（一）

一、验证用到的注解

@Valid	对传到后台的参数的验证
@BindingResult	配合@Valid使用，验证失败后的返回

二、示例

1.传统方式

@PostMapping
    public User create(@RequestBody User user){

        if(StringUtils.isBlank(user.getPassword())){

        }
        //代码省略...
        return user;
    }

2.采用新注解的方式

1）默认的校验

package com.knyel.dto;

import com.fasterxml.jackson.annotation.JsonView;
import org.hibernate.validator.constraints.NotBlank;

import java.util.Date;

public class User {

    public interface UserSimpleView {};
    public interface UserDetailView extends UserSimpleView {};

    private String id;
    private String username;
    @NotBlank
    private  String password;
    private Date birthday;

    @JsonView(UserSimpleView.class)
    public String getUsername (){
        return username;
    }

    public void setUsername (String username){
        this.username = username;
    }
    @JsonView(UserDetailView.class)
    public String getPassword (){
        return password;
    }

    public void setPassword (String password){
        this.password = password;
    }

    @JsonView(UserSimpleView.class)
    public String getId (){
        return id;
    }
    @JsonView(UserSimpleView.class)
    public void setId (String id){
        this.id = id;
    }

    public Date getBirthday (){
        return birthday;
    }

    public void setBirthday (Date birthday){
        this.birthday = birthday;
    }

    @Override
    public String toString (){
        return "User{" + "id='" + id + '\'' + ", username='" + username + '\'' + ", password='" + password + '\'' + ", birthday=" + birthday + '}';
    }
}

 @PostMapping
    public User create(@Valid @RequestBody User user, BindingResult errors){
        if(errors.hasErrors()){
            errors.getAllErrors().stream().forEach(error-> System.out.println(error.getDefaultMessage()));
        }
        //业务处理...
        user.setId("1");
        return user;
    }

输出结果为

may not be empty

也就是应该不能为空

2）自定义校验的错误消息

package com.knyel.dto;

import com.fasterxml.jackson.annotation.JsonView;
import org.hibernate.validator.constraints.NotBlank;

import javax.validation.constraints.Past;
import java.util.Date;

public class User {

    public interface UserSimpleView {};
    public interface UserDetailView extends UserSimpleView {};

    private String id;
    private String username;
    @NotBlank(message="密码不能为空")
    private  String password;
    @Past(message = "生日必须是过去的时间")
    private Date birthday;

    @JsonView(UserSimpleView.class)
    public String getUsername (){
        return username;
    }

    public void setUsername (String username){
        this.username = username;
    }
    @JsonView(UserDetailView.class)
    public String getPassword (){
        return password;
    }

    public void setPassword (String password){
        this.password = password;
    }

    @JsonView(UserSimpleView.class)
    public String getId (){
        return id;
    }
    @JsonView(UserSimpleView.class)
    public void setId (String id){
        this.id = id;
    }

    public Date getBirthday (){
        return birthday;
    }

    public void setBirthday (Date birthday){
        this.birthday = birthday;
    }

    @Override
    public String toString (){
        return "User{" + "id='" + id + '\'' + ", username='" + username + '\'' + ", password='" + password + '\'' + ", birthday=" + birthday + '}';
    }
}