learning java 字符串常用操作

        // 字符串索引取值

        var s = "";

        System.out.println(s.charAt());

        // 字符串比较

        var s1 = "";

        var s2 = "";

        var s3 = "";

        System.out.println(s1.compareTo(s2));

        System.out.println(s1.compareTo(s3));

        //字符串拼接

        var s4 = "allaboutscala";

        var s5 = ".org";

        System.out.println(s4.concat(s5));

        // 字符串前缀及后缀判断

        var s6 = "www.kernel.org";

        var s7 = "www";

        var s8 = "org";

        System.out.println(s6.startsWith(s7));

        System.out.println(s6.endsWith(s8));

        // 字符串拷贝

        char[] s9 = {'','','',''};

        var s10 = "abc";

        s10.getChars(,,s9,);

        System.out.println(s9);

        //字符查找

        System.out.println(s6.indexOf('w'));

        System.out.println(s6.indexOf('w',));

        System.out.println(s6.lastIndexOf('w'));

        System.out.println(s6.replace('w','W'));

        System.out.println(s6.length());

        //字符串截取

        System.out.println(s6.substring());

        System.out.println(s6.substring(,));

        System.out.println(s6.toUpperCase());

        System.out.println(s6.toLowerCase());

        System.out.println(s6.toCharArray());

output:

allaboutscala.org

true

true

ab34

-

WWW.kernel.org

kernel.org

ke

WWW.KERNEL.ORG

www.kernel.org

www.kernel.org