java getCanonicalName getSimpleName和getName的区别和用法

接口:

package com.test;

public interface Fruit {

}

 

 

一个实现类:

package com.test;

public class Apple implements Fruit {

}

 

基本测试类:

package com.test;

import java.util.ArrayList;
import java.util.List;

public class TestName {
    public static void main(String[] args) {
        Fruit apple=new Apple();
        System.out.println(apple.getClass().getCanonicalName());//返回com.test.Apple
        System.out.println(apple.getClass().getSimpleName());//Apple
        System.out.println(apple.getClass().getName());//返回com.test.Apple

        Apple[] arrApple=new Apple[]{};
        System.out.println(arrApple.getClass().getCanonicalName());//返回com.test.Apple[]
        System.out.println(arrApple.getClass().getSimpleName());//返回Apple[]
        System.out.println(arrApple.getClass().getName());//返回[Lcom.test.Apple;

        System.out.println(String.class.getCanonicalName());//返回java.lang.String
        System.out.println(String.class.getSimpleName());//返回String
        System.out.println(String.class.getName());//返回java.lang.String

        System.out.println(int.class.getCanonicalName());//返回int
        System.out.println(int.class.getSimpleName());//返回int
        System.out.println(int.class.getName());//返回int

        Apple a1=new Apple();
        Apple a2=new Apple();
        List<Apple> appleList=new ArrayList<Apple>();
        appleList.add(a1);
        appleList.add(a2);
        System.out.println(appleList.getClass().getCanonicalName());//返回java.util.ArrayList
        System.out.println(appleList.getClass().getSimpleName());//返回ArrayList
        System.out.println(appleList.getClass().getName());//返回java.util.ArrayList

    }
}

 

 

实际应用: hql的泛型查询

 

public <T> List<T> getRecords(Class<T> c,Date startDate,Date endDate){
        StringBuilder hql = new StringBuilder("select t from ");
        hql.append(c.getCanonicalName());
        hql.append(" t where t.statTime>=:startTime and t.statTime<:endTime ");

        Query query = sessionFactory.getCurrentSession().createQuery(hql.toString());
        query.setParameter("startTime", startDate);
        query.setParameter("endTime", endDate);

        return query.list();
    }
}