Scanner

//方式一

package class1;

import java.util.Scanner;
public class ScannerDemo01 {
public static void main(String[] args) {
Scanner scan = new Scanner(System.in);
System.out.println("输入数据：");
String str = scan.next() ;
System.out.println("输入的数据为：" + str );
}

}

方式二：

package class1;
import java.util.Scanner;
public class ScannerDemo02 {
public static void main(String[] args) {
Scanner scan = new Scanner(System.in) ;
scan.useDelimiter("\n") ;
System.out.println("输入数据：");
String str = scan.next();
System.out.println("输入的数据为："+str);
}
}

方式三

package class1;
import java.util.Scanner; 
public class ScannerDemo03 {
public static void main(String[] args) {
Scanner scan = new Scanner(System.in) ;
int i = 0 ;
float f = 0.5f;
System.out.print("输入整数："); 
if(scan.hasNextInt()) {
i = scan.nextInt() ;
System.out.println("整数数据:" + i );
} else {
System.out.println("输入的不是整数！");
}
System.out.print("输入小数："); 
if(scan.hasNextFloat()) {
f = scan.nextFloat();
System.out.println("小数数据：" + f);
} else {
System.out.println("输入的不是小数！");
}

}
}

方式四

package class1;
import java.text.ParseException ;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.Scanner;
public class ScannerDemo04 {
public static void main(String[] args) {
Scanner scan = new Scanner(System.in) ;
System.out.print("输入日期(yyyy-MM-dd): ") ;
String str = null ;
Date date = null;
if(scan.hasNext("^\\d{4}-\\d{2}-\\d{2}$")) {
str = scan.next("^\\d{4}-\\d{2}-\\d{2}$");
try {
date = new SimpleDateFormat("yyyy-MM-dd").parse(str) ;
} catch(ParseException e) {
e.printStackTrace();
}
} else {
System.out.println("输入的日期格式 错误！");
}
System.out.println(date);
}
}

方式五

package class1;
import java.io.File ;
import java.io.FileNotFoundException ;
import java.util.Scanner ;
public class ScannerDemo05 {
public static void main(String[] args) {
File f = new File("d:" + File.separator + "test.txt") ;
Scanner scan = null;
try {
scan = new Scanner(f) ;
} catch (FileNotFoundException e) {
e.printStackTrace() ;
}
StringBuffer str = new StringBuffer();
while (scan.hasNext()) {
str.append(scan.next()).append("\n") ;
}
System.out.println(str);
}
}