本文共 2237 字,大约阅读时间需要 7 分钟。
String s1 = null;
String s2 = null;System.out.println(s1==s2);//true//System.out.println(s1.equals(s2));//NullPointerExceptions1 = s2;System.out.println(s1==s2);//true//System.out.println(s1.equals(s2));//NullPointerExceptionSystem.out.println("***1***");s1 = null;
s2 = "";System.out.println(s1==s2);//false//System.out.println(s1.equals(s2));//NullPointerExceptions1 = s2;System.out.println(s1==s2);//trueSystem.out.println(s1.equals(s2));//trueSystem.out.println("***2***");s1 = "";
s2 = null;System.out.println(s1==s2);//falseSystem.out.println(s1.equals(s2));//falses1 = s2;System.out.println(s1==s2);//true//System.out.println(s1.equals(s2));//NullPointerExceptionSystem.out.println("***3***");s1 = "";
s2 = "";System.out.println(s1==s2);//trueSystem.out.println(s1.equals(s2));//trues1 = s2;System.out.println(s1==s2);//trueSystem.out.println(s1.equals(s2));//trueSystem.out.println("***4***");s1 = new String("");s2 = new String("");System.out.println(s1==s2);//falseSystem.out.println(s1.equals(s2));//trues1 = s2;System.out.println(s1==s2);//trueSystem.out.println(s1.equals(s2));//trueSystem.out.println("***5***");s1 = "null";
s2 = "null";System.out.println(s1==s2);//tureSystem.out.println(s1.equals(s2));//trues1 = s2;System.out.println(s1==s2);//trueSystem.out.println(s1.equals(s2));//trueSystem.out.println("***6***");s1 = new String("null");s2 = new String("null");System.out.println(s1==s2);//flaseSystem.out.println(s1.equals(s2));//trues1 = s2;System.out.println(s1==s2);//trueSystem.out.println(s1.equals(s2));//trueSystem.out.println("***7***");s1 = "abc";
s2 = "abc";System.out.println(s1==s2);//tureSystem.out.println(s1.equals(s2));//trues1 = s2;System.out.println(s1==s2);//trueSystem.out.println(s1.equals(s2));//trueSystem.out.println("***8***");s1 = new String("abc");s2 = new String("abc");System.out.println(s1==s2);//falseSystem.out.println(s1.equals(s2));//trues1 = s2;System.out.println(s1==s2);//trueSystem.out.println(s1.equals(s2));//trueSystem.out.println("***9***");来自 “ ITPUB博客 ” ,链接:http://blog.itpub.net/374079/viewspace-130906/,如需转载,请注明出处,否则将追究法律责任。
转载于:http://blog.itpub.net/374079/viewspace-130906/