java-使用反射实现ORM映射

自定义两个注解

 package com.moon.ROM;

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

 @Target(ElementType.FIELD)
 @Retention(RetentionPolicy.RUNTIME)
 public @interface SexFileAnnotation {
     String name();
     String type();
     int length();

 }

 package com.moon.ROM;

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

 @Target(ElementType.TYPE)
 @Retention(RetentionPolicy.RUNTIME)
 public @interface SexTable {
     String value();

 }

 package com.moon.ROM;
 @SexTable("tb_student")
 public class SxtStudent {
     @SexFileAnnotation(name ="studentName" ,type = "vachar",length = 10)
     private String studentName;
     @SexFileAnnotation(name="age",type = "int",length = 3)
     private int age;
     @SexFileAnnotation(name = "id",type = "int",length = 5)
     private int id;

     public String getStudentName() {
         return studentName;
     }

     public void setStudentName(String studentName) {
         this.studentName = studentName;
     }

     public int getAge() {
         return age;
     }

     public void setAge(int age) {
         this.age = age;
     }

     public int getId() {
         return id;
     }

     public void setId(int id) {
         this.id = id;
     }
 }

 package com.moon.ROM;

 import java.lang.reflect.Field;

 public class Test {
     public static void main(String[] args) {
         try {
             Class clazz = Class.forName("com.moon.ROM.SxtStudent");
 //            Annotation[] annotations = clazz.getAnnotations();
            /* for (Annotation annotation : annotations) {
                 System.out.println(annotation);

             }*/
            SexTable st = (SexTable) clazz.getAnnotation(SexTable.class);
             Field f = clazz.getDeclaredField("studentName");
             SexFileAnnotation sexf = f.getAnnotation(SexFileAnnotation.class);
             System.out.println(sexf.name()+"---"+sexf.type()+"---"+sexf.length());

         } catch (Exception e) {
             e.printStackTrace();
         }

     }
 }