格式化输出

System.out.printf("%s在游戏中击杀了%d名%s%n", "猪猪侠", 1, "史泰龙");
System.out.format("%s在游戏中击杀了%d名%s", "猪猪侠", 1, "史泰龙");

//总长度是8,默认右对齐
System.out.format("%8d",year);
//总长度是8,左对齐
System.out.format("%-8d",year);
//总长度是8,不够补0
System.out.format("%08d,year);
//千位分隔符
System.out.format("%,8d",year*10000);
//小数点位数
System.out.format("%.2f",Math.PI);

character

System.out.println(Character.isLetter('a'));//判断是否为字母
System.out.println(Character.isDigit('a')); //判断是否为数字
System.out.println(Character.isWhitespace(' ')); //是否是空白
System.out.println(Character.isUpperCase('a')); //是否是大写
System.out.println(Character.isLowerCase('a')); //是否是小写
System.out.println(Character.toUpperCase('a')); //转换为大写
System.out.println(Character.toLowerCase('A')); //转换为小写

转义字符

System.out.println("使用\\t制表符可以达到对齐的效果");
System.out.println("abc\tdef");
System.out.println("ab\tdef");
System.out.println("a\tdef");

System.out.println("单引号 ");
System.out.println("abc\'def");
System.out.println("双引号 ");
System.out.println("abc\"def");
System.out.println("反斜杠本身 ");
System.out.println("abc\\def");