Java characters
Example 1: Save time using a character char
package character;
public class TestChar {
public static void main(String[] args) {
char c1 = 'a';
char c2 = '1';//字符1,而非数字1
char c3 = '中';//汉字字符
char c4 = 'ab'; //只能放一个字符
}
}
Example 2: char corresponding wrapper classes
char Character corresponding wrapper class is
package character;
public class TestChar {
public static void main(String[] args) {
char c1 = 'a';
Character c = c1; //自动装箱
c1 = c;//自动拆箱
}
}
Example 3: Character common method
package character;
public class TestChar {
public static void main(String[] args) {
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
String a = 'a'; //不能够直接把一个字符转换成字符串
String a2 = Character.toString('a'); //转换为字符串
}
}
Example 4: Common escape
package character;
public class TestChar {
public static void main(String[] args) {
System.out.println("使用空格无法达到对齐的效果");
System.out.println("abc def");
System.out.println("ab def");
System.out.println("a def");
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("一个\\t制表符长度是8");
System.out.println("12345678def");
System.out.println("换行符 \\n");
System.out.println("abc\ndef");
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");
}
}
Exercise : the Java characters
String read from the console through the Scanner, and the string into a character array
reference conversion:
String str = "abc123";
char[] cs = str.toCharArray();
After conversion into an array of characters, screened console to read the string of capital letters and numbers, and print out
the answer :
package character;
import java.util.Scanner;
public class TestChar {
public static void main(String[] args) {
Scanner s = new Scanner(System.in);
String str = s.nextLine();
char[] cs = str.toCharArray();
for (int i = 0; i < cs.length; i++) {
char c = cs[i];
if(Character.isUpperCase(c) || Character.isDigit(c))
System.out.print(c);
}
}
}