大家好，又见面了，我是你们的朋友全栈君。
1.使用Scanner
使用时需要引入包import java.util.Scanner;首先定义Scanner对象
Scanner sc = new Scanner(System.in);
如果要输入整数，则 int n = sc.nextInt();
String类型的，则String temp = sc.next();
比如：
import java.util.Scanner;public class Test { public static void main(String[] args) {
Scanner scanner = new Scanner(System.in); int[] days = {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31}; int month = -1; while(true) { try {
System.out.print(“请输入月份：”);
month = scanner.nextInt(); if(month >= 1 && month <= 12) { break;
}
System.out.println(“** 请输入正确的月份 **”);
} catch (Exception e) {
System.out.println(“** 格式错误！请输入数字 **”);
scanner.next();
}
}
System.out.println(month + ” 月份有：” + days[month – 1] + ” 天”);
}
}
2.使用BufferedReader
用前需要引入 import java.io.Reader;
BufferedReader br = new BufferedReader( new InputStreamReader(System.in) );
String input = br.readLine();
比如：
==================================================================================================
import java.io.*;
public class importtext {
public static void main(String[] args) {
String st;
int num;
float fnum;
try{
System.out.print(“输入：”);
BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
st = br.readLine();
System.out.print(“输入一个数：”);
num = Integer.parseInt(br.readLine());
System.out.print(“输入一个浮点数：”);
fnum = Float.parseFloat(br.readLine());
System.out.print(“输出：”+st+’\n’);
System.out.print(“输出：”+num+’\n’);
System.out.print(“输出：”+fnum+’\n’);
}catch(IOException e){}
}
}
==================================================================================================
package com.s2;
import java.io.*;
public class Input
{
public static void main(String[] args)throws IOException
{
while(true)
{
BufferedReader buf;
String str;
buf =new BufferedReader(new InputStreamReader(System.in));
System.out.println(“Input a string:”);
str=buf.readLine();
System.out.println(“String=”+str);
}
}
}
==================================================================================================
应该注意的是:Java把从键盘输入的数据一律看作是字符串，因此若要从键盘输入并让系统认可是数值型数据，必须经过转换。
比如：
package com.s2;
import java.io.*;
public class Input
{
public static void main(String[] args)throws IOException
{
while(true)
{
int num;
BufferedReader buf;
String str;
buf =new BufferedReader(new InputStreamReader(System.in));
System.out.println(“Input an integer:”);
str=buf.readLine();
num=Integer.parseInt(str);
System.out.println(“String=”+str);
System.out.println(“Integer=”+str);
}
}
}
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