使用自定义注解和java反射机制实现自定义表映射注解

1.代码demo如下：

package com.itmayiedu.test;

import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
import java.lang.reflect.Field;

@Target(ElementType.FIELD)
@Retention(RetentionPolicy.RUNTIME)
@interface Property{
    String name();
    int length() default 0;
}

@Target(ElementType.TYPE)
@Retention(RetentionPolicy.RUNTIME)
@interface Table{
    String value();
}

@Table("student_test")
class Student{

    @Property(name = "student_id",length = 10)
    private int studentId;
    @Property(name = "student_name",length = 10)
    private String studentName;
    @Property(name = "student_age",length = 10)
    private String studentAge;
}
public class Test {

    public static void main(String[] args) throws Exception {
        Class forName = Class.forName("com.itmayiedu.test.Student");
        //获取Student类中所有的属性
        Field[] fields = forName.getDeclaredFields();

        StringBuilder stringBuilder = new StringBuilder("select ");
        for (int i = 0;i