JAVA Scanner 类

Scanner 是一个新的操作类，是在java.util 包中提供的一个操作类，使用此类可以方便的完成输入流的输入操作：

package org.scannerdemo;

import java.util.Scanner;

public class ScannerDemo01 {

	/**
	 * @param args
	 */
	@SuppressWarnings("resource")
	public static void main(String[] args) {
		// TODO Auto-generated method stub
		Scanner scan = new Scanner(System.in);
		
		int i =0;
		
		if (scan.hasNextInt()){
			i = scan.nextInt();
		}
		
		System.out.println("i:=" +i);
		
		
		
	}

}

package org.scannerdemo;

import java.util.Scanner;

public class ScannerDemo02 {

	/**
	 * @param args
	 */
	@SuppressWarnings("resource")
	public static void main(String[] args) {
		// TODO Auto-generated method stub
		Scanner scan = new Scanner(System.in);
		
		String str = "";
		
		if (scan.hasNext()){
			str = scan.next();
		}
		
		System.out.println("str:=" +str);
	}

}

支持正则匹配：

package org.scannerdemo;

import java.util.Scanner;

public class ScannerDemo04 {

	/**
	 * @param args
	 */
	@SuppressWarnings("resource")
	public static void main(String[] args) {
		// TODO Auto-generated method stub
		Scanner scan = new Scanner(System.in);
		
		String str = "";
		
		if (scan.hasNext("\\d{4}-\\d{2}-\\d{2}")){
			str = scan.next();
		}
		
		System.out.println("str:=" +str);
	}

}

支持 InputSteam：

package org.scannerdemo;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.util.Scanner;

public class ScannerDemo03 {

	/**
	 * @param args
	 * @throws FileNotFoundException 
	 */
	@SuppressWarnings("resource")
	public static void main(String[] args) throws FileNotFoundException {
		// TODO Auto-generated method stub
		File file = new File ("d:\\1.txt");
		
		Scanner scan = new Scanner(new FileInputStream(file));
		
		scan.useDelimiter("\n");
		
		StringBuffer buf = new StringBuffer();
		
		while (scan.hasNext()){
			buf.append(scan.next()).append("\n");
		}
		
		System.out.println(buf);
	}

}