Java中equalsIgnoreCase()方法的使用

public class Test {
    public static void main(String args[]) {
        String s1= new String("today");
        String s2= s1;
        String s3= new String("today");
        String s4= new String("TODAY");
        boolean retVal;
 
        str = s1.equals( s2);
        System.out.println("返回值 = " + str);
 
        str = s3.equals( s4);
        System.out.println("返回值 = " + str );
 
        str  = s1.equalsIgnoreCase( s4);
        System.out.println("返回值 = " + str );
    }
}

public static void main(String[] args) {
        String a="aaa";
        String b="AAA";
        String c="aaa";

        System.out.println("a:"+a + "\n" +"b:"+ b + "\n" +"c:"+ c);
        System.out.println("-----------");
        System.out.println(a.equals(b));
        System.out.println(a.equals(c));        // 区分大小写，比较字符串内容
        System.out.println(a.equalsIgnoreCase(b));   //不区分大小，比较字符串内容
        System.out.println("----------");
        System.out.println(a == b);
        System.out.println(a == c);
        System.out.println(b == c);
    }