Java利用反射查看类属性和方法例子

喜欢ヅ旅行 2022-08-10 15:56 177阅读 0赞

import java.lang.reflect.*;
    import java.util.Arrays;//the class that will be reflected should be imported
    import java.util.ArrayList;
    import java.util.LinkedList;
    //import java.lang.reflect.Field;
    public class TestOfReflect{
    	public static void printClassInfo(String s){
    		try{
    		Class cs=Class.forName(s);
    		Field [] fl=cs.getDeclaredFields();
    		System.out.println(fl.length);
    		for(int i=0;i<fl.length;i++){
    			System.out.println("name:"+fl[i].getName());
    			System.out.println("decl class:"+fl[i].getDeclaringClass());
    			System.out.println("type:"+fl[i].getType());
    		}
    	}
    	catch(Throwable e){
    		System.err.println(e);
    	}
    	}
    	public static void printMethodInfo(String s){
    		try{
    		Class cs=Class.forName(s);
    		Method [] md=cs.getDeclaredMethods();
    		System.out.println(md.length);
    		for(int i=0;i<md.length;i++){
    			System.out.println("method"+(i+1)+"--->"+md[i]);	
    		}
    	}
    	catch(Throwable e){
    		System.err.println(e);
    	}
    	}
    	public static void main(String[] args) {
    		String c1="java.util.ArrayList";
    		String c2="java.util.LinkedList";
    		System.out.println("member val:");
    		printClassInfo(c1);
    		printClassInfo(c2);
    		System.out.println("member methods:");
    		printMethodInfo(c1);
    		printMethodInfo(c2);
    	}
    }

结果member val:
    6
    name:serialVersionUID
    decl class:class java.util.ArrayList
    type:long
    name:DEFAULT_CAPACITY
    decl class:class java.util.ArrayList
    type:int
    name:EMPTY_ELEMENTDATA
    decl class:class java.util.ArrayList
    type:class [Ljava.lang.Object;
    name:elementData
    decl class:class java.util.ArrayList
    type:class [Ljava.lang.Object;
    name:size
    decl class:class java.util.ArrayList
    type:int
    name:MAX_ARRAY_SIZE
    decl class:class java.util.ArrayList
    type:int
    4
    name:size
    decl class:class java.util.LinkedList
    type:int
    name:first
    decl class:class java.util.LinkedList
    type:class java.util.LinkedList$Node
    name:last
    decl class:class java.util.LinkedList
    type:class java.util.LinkedList$Node
    name:serialVersionUID
    decl class:class java.util.LinkedList
    type:long
    member methods:
    41
    method1--->public void java.util.ArrayList.add(int,java.lang.Object)
    method2--->public boolean java.util.ArrayList.add(java.lang.Object)
    method3--->public java.lang.Object java.util.ArrayList.remove(int)
    method4--->public boolean java.util.ArrayList.remove(java.lang.Object)
    method5--->public java.lang.Object java.util.ArrayList.get(int)
    method6--->public java.lang.Object java.util.ArrayList.clone()
    method7--->public int java.util.ArrayList.indexOf(java.lang.Object)
    method8--->public void java.util.ArrayList.clear()
    method9--->public boolean java.util.ArrayList.contains(java.lang.Object)
    method10--->public boolean java.util.ArrayList.isEmpty()
    method11--->public int java.util.ArrayList.lastIndexOf(java.lang.Object)
    method12--->public int java.util.ArrayList.size()
    method13--->public java.util.List java.util.ArrayList.subList(int,int)
    method14--->public java.lang.Object[] java.util.ArrayList.toArray()
    method15--->public java.lang.Object[] java.util.ArrayList.toArray(java.lang.Object[])
    method16--->static int java.util.ArrayList.access$100(java.util.ArrayList)
    method17--->public boolean java.util.ArrayList.addAll(java.util.Collection)
    method18--->public boolean java.util.ArrayList.addAll(int,java.util.Collection)
    method19--->public java.util.Iterator java.util.ArrayList.iterator()
    method20--->static java.lang.Object[] java.util.ArrayList.access$200(java.util.ArrayList)
    method21--->private void java.util.ArrayList.readObject(java.io.ObjectInputStream) throws java.io.IOException,ja
    method22--->private void java.util.ArrayList.writeObject(java.io.ObjectOutputStream) throws java.io.IOException
    method23--->public java.lang.Object java.util.ArrayList.set(int,java.lang.Object)
    method24--->public void java.util.ArrayList.ensureCapacity(int)
    method25--->public void java.util.ArrayList.trimToSize()
    method26--->private void java.util.ArrayList.ensureCapacityInternal(int)
    method27--->java.lang.Object java.util.ArrayList.elementData(int)
    method28--->private void java.util.ArrayList.grow(int)
    method29--->private static int java.util.ArrayList.hugeCapacity(int)
    method30--->public java.util.ListIterator java.util.ArrayList.listIterator(int)
    method31--->public java.util.ListIterator java.util.ArrayList.listIterator()
    method32--->public boolean java.util.ArrayList.removeAll(java.util.Collection)
    method33--->protected void java.util.ArrayList.removeRange(int,int)
    method34--->public boolean java.util.ArrayList.retainAll(java.util.Collection)
    method35--->private java.lang.String java.util.ArrayList.outOfBoundsMsg(int)
    method36--->private void java.util.ArrayList.rangeCheckForAdd(int)
    method37--->private boolean java.util.ArrayList.batchRemove(java.util.Collection,boolean)
    method38--->private void java.util.ArrayList.ensureExplicitCapacity(int)
    method39--->private void java.util.ArrayList.fastRemove(int)
    method40--->private void java.util.ArrayList.rangeCheck(int)
    method41--->static void java.util.ArrayList.subListRangeCheck(int,int,int)
    54
    method1--->public boolean java.util.LinkedList.add(java.lang.Object)
    method2--->public void java.util.LinkedList.add(int,java.lang.Object)
    method3--->public java.lang.Object java.util.LinkedList.remove(int)
    method4--->public java.lang.Object java.util.LinkedList.remove()
    method5--->public boolean java.util.LinkedList.remove(java.lang.Object)
    method6--->public java.lang.Object java.util.LinkedList.get(int)
    method7--->public java.lang.Object java.util.LinkedList.clone()
    method8--->public int java.util.LinkedList.indexOf(java.lang.Object)
    method9--->public void java.util.LinkedList.clear()
    method10--->public boolean java.util.LinkedList.contains(java.lang.Object)
    method11--->public int java.util.LinkedList.lastIndexOf(java.lang.Object)
    method12--->public int java.util.LinkedList.size()
    method13--->public java.lang.Object[] java.util.LinkedList.toArray(java.lang.Object[])
    method14--->public java.lang.Object[] java.util.LinkedList.toArray()
    method15--->public boolean java.util.LinkedList.addAll(java.util.Collection)
    method16--->public boolean java.util.LinkedList.addAll(int,java.util.Collection)
    method17--->public java.lang.Object java.util.LinkedList.pop()
    method18--->public void java.util.LinkedList.push(java.lang.Object)
    method19--->private void java.util.LinkedList.readObject(java.io.ObjectInputStream) throws java.io.IOException,java.lang.ClassNotFoundException
    method20--->private void java.util.LinkedList.writeObject(java.io.ObjectOutputStream) throws java.io.IOException
    method21--->public java.lang.Object java.util.LinkedList.poll()
    method22--->public java.lang.Object java.util.LinkedList.set(int,java.lang.Object)
    method23--->public java.util.ListIterator java.util.LinkedList.listIterator(int)
    method24--->private java.lang.String java.util.LinkedList.outOfBoundsMsg(int)
    method25--->public java.lang.Object java.util.LinkedList.peek()
    method26--->public void java.util.LinkedList.addFirst(java.lang.Object)
    method27--->public void java.util.LinkedList.addLast(java.lang.Object)
    method28--->private void java.util.LinkedList.checkElementIndex(int)
    method29--->private void java.util.LinkedList.checkPositionIndex(int)
    method30--->public java.util.Iterator java.util.LinkedList.descendingIterator()
    method31--->public java.lang.Object java.util.LinkedList.element()
    method32--->public java.lang.Object java.util.LinkedList.getFirst()
    method33--->public java.lang.Object java.util.LinkedList.getLast()
    method34--->private boolean java.util.LinkedList.isElementIndex(int)
    method35--->private boolean java.util.LinkedList.isPositionIndex(int)
    method36--->void java.util.LinkedList.linkBefore(java.lang.Object,java.util.LinkedList$Node)
    method37--->private void java.util.LinkedList.linkFirst(java.lang.Object)
    method38--->void java.util.LinkedList.linkLast(java.lang.Object)
    method39--->java.util.LinkedList$Node java.util.LinkedList.node(int)
    method40--->public boolean java.util.LinkedList.offer(java.lang.Object)
    method41--->public boolean java.util.LinkedList.offerFirst(java.lang.Object)
    method42--->public boolean java.util.LinkedList.offerLast(java.lang.Object)
    method43--->public java.lang.Object java.util.LinkedList.peekFirst()
    method44--->public java.lang.Object java.util.LinkedList.peekLast()
    method45--->public java.lang.Object java.util.LinkedList.pollFirst()
    method46--->public java.lang.Object java.util.LinkedList.pollLast()
    method47--->public java.lang.Object java.util.LinkedList.removeFirst()
    method48--->public boolean java.util.LinkedList.removeFirstOccurrence(java.lang.Object)
    method49--->public java.lang.Object java.util.LinkedList.removeLast()
    method50--->public boolean java.util.LinkedList.removeLastOccurrence(java.lang.Object)
    method51--->private java.util.LinkedList java.util.LinkedList.superClone()
    method52--->java.lang.Object java.util.LinkedList.unlink(java.util.LinkedList$Node)
    method53--->private java.lang.Object java.util.LinkedList.unlinkFirst(java.util.LinkedList$Node)
    method54--->private java.lang.Object java.util.LinkedList.unlinkLast(java.util.LinkedList$Node)