一、基本数据类型与 String类型转换

将基本数据类型转成String类型，或者将String类型转成基本数据类型。

1、基本数据类型转String类型

package demo01;public class String01 {public static void main(String[] args) {int a1 = 10;long a2 = 100;float a3 = 100.0f;double a4 = 10.00;boolean a5 = false;System.out.println(a1 + "");System.out.println(a2 + "");System.out.println(a3 + "");System.out.println(a4 + "");System.out.println(a5 + "");}
}

2、String类型转基本数据类型

package demo01;
import java.lang.Integer;
public class String02 {public static void main(String[] args) {String num = "321";int a1 = Integer.parseInt(num);long a2 = Long.parseLong(num);float a3 = Float.parseFloat(num);double a4 = Double.parseDouble(num);boolean a5 = Boolean.parseBoolean("false");short a6 = Short.parseShort(num);char a7 = num.charAt(0);System.out.println(a1);System.out.println(a2);System.out.println(a3);System.out.println(a4);System.out.println(a5);System.out.println(a6);System.out.println(a7);}
}

 

练习一

package demo01;public class Test02 {public static void main(String[] args) {int n1;n1 = 13;int n2;n2 = 17;int n3;n3 = n1 + n2; //30System.out.println("n3=" + n3);int n4 = 38;int n5 = n4 - n3; //8System.out.println("n5=" + n5);}
}

 

 练习二

package demo01;public class Test03 {public static void main(String[] args) {char a1 = '\n';char a2 = '\t';char a3 = '\r';char a4 = '\\';char a5 = '1';char a6 = '2';char a7 = '3';System.out.println(a1);System.out.println(a2);System.out.println(a3);System.out.println(a4);System.out.println(a5);System.out.println(a6);System.out.println(a7);}
}

 

  练习三

保存两本书名，用+拼接，看效果。保存两个性别，用加号拼接，看效果。保存两本书价格，用加号拼接，看效果。

package demo01;public class Test04 {public static void main(String[] args) {String book1 = "小黄书";String book2 = "小红书";char age1 = '男';char age2 = '女';double money1 = 59.9;double money2 = 85.7;System.out.println(book1 + book2);System.out.println(age1 + age2);System.out.println(money1 + money2);}
}