114 lines
2.6 KiB
Java
114 lines
2.6 KiB
Java
package 类;
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import java.util.ArrayList;
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import java.util.Date;
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import java.util.List;
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enum E { A, B };//枚举类型E
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public class ClassEx {
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public static void main(String[] args) throws Exception {
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//第1种获取Class实例的方法 ：对象名.getClass()，原始类型、接口类型对应的Class实例不能用这种方法获取
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//类类型
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Class c = "foo".getClass();
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System.out.println(c);
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c = System.out.getClass();
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System.out.println(c);
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Date date=new Date();
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c=date.getClass();
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System.out.println(c);
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//接口类型
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List<Date> array=new ArrayList<Date>();
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c=array.getClass();
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System.out.println(c);
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//数组类型
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int[] a=new int[10];
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c=a.getClass();
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System.out.println(c+" "+c.getCanonicalName());
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char[] b=new char[10];
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c=b.getClass();
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System.out.println(c+" "+c.getName());
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double[] d=new double[10];
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c=d.getClass();
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System.out.println(c);
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long[] l=new long[10];
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c=l.getClass();
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System.out.println(c);
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Date[] f=new Date[10];
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c=f.getClass();
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System.out.println(c+" "+c.getCanonicalName());
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//枚举类型
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E e=E.A;
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c=e.getClass();
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System.out.println(c);
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System.out.println("*****************************");
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//基本类型，编译错误
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//int a=10;
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//c=a.getClass();
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//第2种获取Class实例的方法 ：类型名.class，所有类型对应的Class实例都可以用这种方法获取
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c=String.class;
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System.out.println(c);
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c=Date.class;
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System.out.println(c);
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c=List.class;
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System.out.println(c);
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c=int.class;
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System.out.println(c);
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c=int[][].class;
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System.out.println(c);
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c=Date[][].class;
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System.out.println(c);
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c=E.class;
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System.out.println(c);
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System.out.println("*****************************");
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//第3种获取Class实例的方法 ：Class.forName(类全名字符串)，原始类型对应的Class实例不可以用这种方法获取
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c=Class.forName("java.lang.String");
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System.out.println(c);
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c=Class.forName("java.util.List");
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System.out.println(c);
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c=Class.forName("[I");//int数组类型int[]
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System.out.println(c);
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c = Class.forName("[D");//double型数组double[]
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System.out.println(c);
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c = Class.forName("[[Ljava.lang.String;");//String二维数组String[][]
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System.out.println(c);
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c=Class.forName("类.E");
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System.out.println(c);
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System.out.println("*****************************");
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//基本类型包装类中的TYPE成员的值是基本类型对应的Class类实例
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c=Double.TYPE;
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System.out.println(c);
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c=Void.TYPE;
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System.out.println(c);
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}
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}
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