java 基于注解形式的校验规则

Myth丶恋晨 2023-10-10 10:06 40阅读 0赞

package com;
    
    import java.awt.Checkbox;
    import java.lang.annotation.ElementType;
    import java.lang.annotation.Target;
    import java.lang.reflect.Field;
    import java.security.KeyStore.PrivateKeyEntry;
    
    //基于注解形式的校验规则
    public class Damo7 {
    	public static void main(String[] args) {
    		Xman x=new Xman(100,"小红","三天三夜");
    		x.setContent(null);
    		x.setGender(1);
    
    		
    		BeanVaildator.check(x);
    	}
    }
    //注解做代码层面的简单配置
    @Target(ElementType.FIELD)//作用于成员变量
    @interface Rule{
    	int max() default 0;
    	int min() default 0;
    	//信息描述
    	String value() default "";
    	//能否为空
    	boolean isNull() default true;
    }
    
    //bean的校验规则
    class BeanVaildator{
    	public static <T> void check(T t) {
    		//拿到t中的每一个属性
    		Class clazz=t.getClass();
    		Field[] fs=clazz.getDeclaredFields();
    		for(Field field:fs) {
    			//强制访问私有属性
    			field.setAccessible(true);
    			try {
    				Object obj=field.get(t);
    				//如果满足rule可以为空，就可以为空，否则不能为空
    				Rule rule=field.getAnnotation(Rule.class);
    				if (rule!=null) {
    					//校验规则的规范
    					int max=rule.max();
    					int min=rule.min();
    					String valueAnn=rule.value();
    					boolean isNull=rule.isNull();
    					//取出实际值
    					Object value=field.get(t);
    					if (isNull) {
    						if (value==null) {
    							continue;
    						}
    					}else {
    						//如果不能为空的情况下为空l
    						if (value==null) throw new MyParamException(valueAnn+"该变量不能为空");				
    					}
    					//是Integer 还是String
    					if (value instanceof String) {
    						int strLength=((String)value).length();
    						if(strLength<min || strLength>max) {
    							throw new MyParamException(valueAnn+"字符串长度限制出问题");
    						}
    					}else if(value instanceof Integer){
    						if((Integer)value<min||(Integer)value>max){
    							throw new MyParamException(valueAnn+"值大小越界");
    						}
    					}
    				}
    				
    			} catch (Exception e) {
    				// TODO Auto-generated catch block
    				e.printStackTrace();
    			} 
    		}
    	}
    }
    
    //设置一个自定义异常
    class MyParamException extends RuntimeException{
    	private String message;
    	private Exception e;
    	public MyParamException(String message) {
    		super(message);
    		this.message=message;
    	}
    	public MyParamException(Exception e) {
    		super(e);
    		this.e=e;
    	}
    	public MyParamException() {
    		this.message="参数异常";
    	}
    }
    
    class Xman{
    	//年龄不超过200；
    	@Rule(min=1,max=200,value="年龄")
    	private Integer age;
    	//名字不超五个字
    	@Rule(min=0,max=5,value="名字")
    	private String name;
    	//不能为空
    	@Rule(isNull=true,value="能力描述",min=0,max=2000)
    	private String content;//能力描述
    	@Rule(isNull=false,value="性别",min=1,max=2)
    	private Integer gender=0;
    	
    	public Xman() {
    		super();
    	}
    	public Xman(Integer age, String name, String content) {
    		super();
    		this.age = age;
    		this.name = name;
    		this.content = content;
    	}
    	public Integer getGender() {
    		return gender;
    	}
    	public void setGender(Integer gender) {
    		this.gender = gender;
    	}
    	public Integer getAge() {
    		return age;
    	}
    	public void setAge(Integer age) {
    		this.age = age;
    	}
    	public String getName() {
    		return name;
    	}
    	public void setName(String name) {
    		this.name = name;
    	}
    	public String getContent() {
    		return content;
    	}
    	public void setContent(String content) {
    		this.content = content;
    	}
    	@Override
    	public String toString() {
    		return "Xman [age=" + age + ", name=" + name + ", content=" + content + "]";
    	}
    }
    class ClassRoom{
    	private String name;
    	private Integer id;
    	private Integer size;
    	
    	public String getName() {
    		return name;
    	}
    
    
    	public void setName(String name) {
    		this.name = name;
    	}
    
    
    	public int getId() {
    		return id;
    	}
    
    
    	public void setId(int id) {
    		this.id = id;
    	}
    
    
    	public int getSize() {
    		return size;
    	}
    
    
    	public void setSize(int size) {
    		this.size = size;
    	}
    
    
    	@Override
    	public String toString() {
    		return "ClassRoom [name=" + name + ", id=" + id + ", size=" + size + "]";
    	}
    class School {
    	private Integer id;
    	private String name;
    	private Integer age;
    	@Override
    	public String toString() {
    		return "School [id=" + id + ", name=" + name + ", age=" + age + "]";
    	}
    }