Java 字符串

字符串转化

byte Byte.parseByte()

short Short.parseShort()

int Integer.parseInteger()

float Float.parseFloat()

double Double.parseDouble()

boolean Boolean.parseBoolean()

char Character.parseCharacter()

样例代码

String s1="123";
String s2="456";
int a=Integer.parseInt(s1);  //字符串转化为数字并相加
int b=Integer.parseInt(s2);
System.out.print(a+b);
输出结果:`579`
StringBuffer buf=new StringBuffer("Hello World!"); //字符串连接
buf.append("WeCome!");
System.out.print(buf.toString());
输出结果:`Hello world! WeCome!`

import java.util.StringTokenizer;
String S="Hello,class,Welcome to Java!Java is very important.";
String del=" ,.!";
StringTokenizer tok=new StringTokenizer(S,del);  //统计字符串词数,并输出
System.out.println(tok.countTokens());
while(tok.hasMoreElements())
	System.out.println(tok.nextToken());

输出结果:

`9
Hello
class
Welcome
to
Java
Java
is
very
important`
package classtoday;

public class classto1 {
	public static void main(String[] args) {
		Car ca=new Car();
		Motorbike mo=new Motorbike();
		ca.getCar();
		mo.getCar();
	}

}

abstract class Vehicle{
	abstract void getCar(); //抽象方法
}

class Car extends Vehicle{
	void getCar(){
		System.out.println("四轮车"); // 实现抽象方法
	}
}

class Motorbike extends Vehicle{
	void getCar(){
		System.out.println("双轮车"); // 实现抽象方法
	}
}

输出结果:

`四轮车
双轮车`