Scanner的使用

JQInputData工具类

package Scanner;
import java.io.*;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.*;


public class JQInputData {
    public static Scanner scan = new Scanner (System.in);
    
    /**从键盘获取字符串*/
    public static String getString(String info){
        Scanner scan = new Scanner (System.in);
        scan.useDelimiter("\n");//设置结束标识为换行,不然字符串没有办法加入空格
        System.out.println(info);
        String str = null;
        str =  scan.next();
        return str;
    }
    
    /**从键盘获取int类型数据*/
    public static int getInt(String info,String err) throws IOException{
        boolean flag = true;
        int tmp = 0;
        while(flag){
            System.out.println(info);
            if(scan.hasNextInt()){
                tmp = scan.nextInt();
                flag = false;
            }else{
                System.out.println(err);
                scan.next(); //如果不满足,那么一定要用scan.next()把刚才输入的内容接收了,不然会无休止判断下去
            }
        }   
        return tmp;
    }
    
    /**从键盘获取float类型数据*/
    public static float getFloat(String info,String err){
        boolean flag = true;
        float tmp = 0;
        while(flag){
            System.out.println(info);
            if (scan.hasNextFloat()){ 
                tmp = scan.nextFloat();
                flag = false;
            }else{
                System.out.println(err);
                scan.next();
            }
        }   
        return tmp;
    }
    
    /**从键盘获取日期(2016-06-30)转成Date对象*/
    public static Date getDate(String info,String err) throws ParseException{
        boolean flag = true;
        Date tmp = null;
        while(flag){
            System.out.println(info);
            if (scan.hasNext("([0-9]{3}[1-9]|[0-9]{2}[1-9][0-9]{1}|[0-9]{1}[1-9][0-9]{2}|[1-9][0-9]{3})-(((0[13578]|1[02])-(0[1-9]|[12][0-9]|3[01]))|((0[469]|11)-(0[1-9]|[12][0-9]|30))|(02-(0[1-9]|[1][0-9]|2[0-8])))")){ 
                String str = scan.next("([0-9]{3}[1-9]|[0-9]{2}[1-9][0-9]{1}|[0-9]{1}[1-9][0-9]{2}|[1-9][0-9]{3})-(((0[13578]|1[02])-(0[1-9]|[12][0-9]|3[01]))|((0[469]|11)-(0[1-9]|[12][0-9]|30))|(02-(0[1-9]|[1][0-9]|2[0-8])))");
                tmp = new SimpleDateFormat("yyyy-MM-dd").parse(str);   
                flag = false;
            }else{
                System.out.println(err);
                scan.next();
            }
        }   
        return tmp;
    }
    
}

Test

package Scanner;
import java.io.IOException;
import java.util.Scanner;

public class Test {

    public static void main(String[] args) throws IOException {

        System.out.println("您输入的文本是:"+JQInputData.getString("\n请输入文本:"));
        
        
        System.out.println("您输入的整数是:"+JQInputData.getInt("\n请输入整数:","不对,请重新输入:"));
        
        
        System.out.println("您输入的浮点数是:"+JQInputData.getFloat("\n请输入浮点数:","不对,请重新输入:"));
    
    }

}

Test2

package Scanner;

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

public class Test2 {
    
    public static void main(String[] args) throws FileNotFoundException {
        String path = JQPathTool.getPath(JQPathTool.Desktop + "/io.txt");
        File f = new File(path);
        Scanner scan = new Scanner(f); // 这里来源是File 不能填Path,否则会对路径字符串进行读取
        StringBuffer buf = new StringBuffer();
        while (scan.hasNext()) {
            buf.append(scan.next()).append("\n");
        }
        System.out.print(buf);
    }
    
}

Paste_Image.png