string_int.java

String int 字符串常量池 包装类型 函数参数 值传递引用传递 的 内存分配例子——源码 代码段： public static void fun_ref (Ref_test ref_

package string_int;

public class String_int {
	
	public static void main(String[] args) {
		  String s1="abc"; 
		  String s2="abc";
		  String s3=s1; 
		  String s4=new String("abc");
		  String s5=new String(s1);
	if (s1==s2)
	    System.out.println("s1==s2");
	else 
		System.out.println("s1!=s2");
	if (s3==s2)
	    System.out.println("s3==s2");
	else 
		System.out.println("s3!=s2");
	if (s4==s2)
	    System.out.println("s4==s2");
	else 
		System.out.println("s4!=s2");
	if (s5==s2)
	    System.out.println("s5==s2");
	else 
		System.out.println("s5!=s2");
	if (s5==s4)
	    System.out.println("s5==s4");
	else 
		System.out.println("s5!=s4");
	
	if (s1.equals(s2))
        System.out.println("s1.equals(s2)");
	else 
		System.out.println(" not s1.equals(s2)");
	if (s1.equals(s3))
	    System.out.println("s1.equals(s3)");
	else 
		System.out.println(" not s1.equals(s3)");
	if (s4.equals(s3))
	    System.out.println("s4.equals(s3)");
	else 
		System.out.println(" not s4.equals(s3)");
	if (s5.equals(s2))
	    System.out.println("s5.equals(s2)");
	else 
		System.out.println(" not s5.equals(s2)");
	if (s5.equals(s4))
	    System.out.println("s5.equals(s4)");
	else 
		System.out.println(" not s5.equals(s4)");
	
	int i1=10,i2=10,i3=i1;
	if(i1==i2)
		 System.out.println("i1==i2");
	 else
		 System.out.println("i1!=i2");
	
	if(i1==i3)
		 System.out.println("i1==i3");
	 else
		 System.out.println("i1!=i3");
	
	if(i2==i3)
		 System.out.println("i2==i3");
	 else
		 System.out.println("i2!=i3");
	 System.out.println("***********");
	
//	if(i1.equals(i3))
//		 System.out.println("i2==i3");
//	 else
//		 System.out.println("i2!=i3");
	 
	Integer I1=33;
	Integer I2=33;
	Integer I3=I1;
	Integer I6=new Integer(I1);
	Integer I4=new Integer(8);
	Integer I5=new Integer(8);
	if(I1==I2)
		 System.out.println("I1==I2");
	else
		 System.out.println("I1!=I2");
	
	if(I1==I3)
		 System.out.println("I1==I3");
	else
		 System.out.println("I1!=I3");
	
	if(I2==I3)
		 System.out.println("I2==I3");
	else
		 System.out.println("I2!=I3");

	if(I1==I6)
		 System.out.println("I1==I6");
	else
		 System.out.println("I1!=I6");

	if(I4==I3)
		 System.out.println("I4==I3");
	else
		 System.out.println("I4!=I3");
	if(I4==I5)
		 System.out.println("I4==I5");
	else
		 System.out.println("I4!=I5");
	
	
	if(I1.equals(I3))
		 System.out.println("I1 equals I3");
    else
	 System.out.println("not I1 equals I3");
	
	if(I4.equals(I3))
		 System.out.println("I4 equals I3");
   else
	   System.out.println("not I4 equals I3");
	if(I4.equals(I5))
		 System.out.println("I4 equals I5");
  else
	   System.out.println("not I4 equals I5");

	}

}