| 失效链接处理 |
|
反射操作注解与反射操作泛型 PDF 下载
本站整理下载：
相关截图：
主要内容：
利用注解和反射完成类和表结构的映射关系
代码：
package com.chao.reflection;
import java.lang.annotation.*;
import java.lang.reflect.Field;
//练习反射操作注解
public class Test12 {
public static void main(String[] args) throws ClassNotFoundException, NoSuchFieldException {
Class c1 = Class.forName("com.chao.reflection.Student2");
//通过反射获得注解
Annotation[] annotations = c1.getAnnotations();
for (Annotation annotation : annotations) {
System.out.println(annotation);
}
//获得注解的value的值.
Tablechao tablechao = (Tablechao)c1.getAnnotation(Tablechao.class);
String value = tablechao.value();
System.out.println(value);
//获得类指定的注解
Field f = c1.getDeclaredField("id");
Fieldchao annotation = f.getAnnotation(Fieldchao.class);
System.out.println(annotation.columnName());
System.out.println(annotation.type());
System.out.println(annotation.length());
}
}
@Tablechao("db_student")
class Student2{
@Fieldchao(columnName = "db_id",type = "int",length = 10)
private int id;
@Fieldchao(columnName = "db_age",type = "int",length = 10)
private int age;
@Fieldchao(columnName = "db_name",type = "varchar",length = 3)
private String name;
public Student2() {
}
public Student2(int id, int age, String name) {
this.id = id;
this.age = age;
this.name = name;
}
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
@Override
public String toString() {
return "Student2{" +
"id=" + id +
", age=" + age +
", name='" + name + '\'' +
'}';
}
}
//类名的注解
@Target(ElementType.TYPE)
@Retention(RetentionPolicy.RUNTIME)
@interface Tablechao{
String value();
}
//属性的注解
@Target(ElementType.FIELD)
@Retention(RetentionPolicy.RUNTIME)
@interface Fieldchao{
String columnName();
String type();
int length();
}
|
| Java1234官方群25： | 
|
| Java1234官方群25： | 838462530 |
苏公网安备 32061202001004号
