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public class User<T1,T2,T3>{
private T1 t1;
private T2 t2;
private T3 t3;
public User(){}
public User(T1 t1,T2 t2,T3 t3){
this.t1=t1;
this.t2=t2;
this.t3=t3;
}
public void main(String[] args){
User u1=new User(1,"aa",23);
User u2=new User("aa",new Date(),12);
}
}
class User2{
private Object t1;
private Object t2;
private Object t3;
public User2(){}
public User2(Object t1,Object t2,Object t3){
this.t1=t1;
this.t2=t2;
this.t3=t3;
}
public void main(String[] args){
User u1=new User(1,"aa",23);
User u2=new User("aa",new Date(),12);
}
}
public static <E> void debug(E e){
.....
}
//这个e可以是任何的java对象
//在调用的时候,可以不用做什么处理,在观察类方法说明时,它会自动将参数类型转化为你传的参数
//还有?类型,?表示任何类型
List<?> list=...
List<? extends Object>
//还有pk
public class BaseDao<E,PK extends Serializable>{
//这里的pk一般理解为主键,常用在数据库操作上面
public E getById(PK pk){
//.....
}
}
//用的话就这样用
BaseDao<JavaBean,java.lang.Integer> bd = new BaseDao<JavaBean,java.lang.Intger>();
//关于T,我个人直接把它理解为type,类的type
//如
public static <T extends java.util.Date> T s2d(String s,Class<T> type){
}
s2d("20001010",java.sql.Date.class);
public ID save(T entity) {
logger.debug("saving Entity instance");
try
{
logger.debug("save successful");
return (ID)getHibernateTemplate().save(entity);
}
catch (RuntimeException re)
{
logger.error("save failed", re);
throw re;
}
}
public class DBTransFlow<T>
{
...
}