package com.stringtest;
/*
  一个8位的字符串例如：abcdefgh， 截取他末尾成对出现的0，例如 

10000000 截取后的结果：10 

12345600 截取后的结果：123456 

12340000 截取后的结果是：1234 

10000001：则不做截取操作 

10101010：则不做截取操作
*/
public class SubDoubleZero {
	public static void main(String[] args) {   
		        String str = "1234570000";   
		        String str1 = "123400010";   
		        String str2 = "12342000";   
		        System.out.println(subDoubleZero(str));   
		        System.out.println(subDoubleZero(str1));   
		        System.out.println(subDoubleZero(str2));   
		  
		    }   
		  
		    public static String subDoubleZero(String str) { 
		    	 //正则表达式
		    	str = str.replaceAll("((00)*$)", "");
		        return str;   
		    }  

}

import java.io.BufferedReader;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.LineNumberReader;
import java.util.ArrayList;
import java.util.LinkedList;
//一行一行地读文件,并输出某行的内容
public class ReadFileTest {
	
	public static void main(String[] args) {
		try {
			//读test.txt文件
			BufferedReader bread = new BufferedReader(new FileReader("f:/file/test.txt"));
			ArrayList<String> list = new ArrayList<String>();
			String rline;			
			//逐行地读
			while((rline = bread.readLine())!=null){				
				list.add(rline);	//把每行增加到数组							
			}
			//输出第二行的内容
			for(int i=1;i<2;i++){
				System.out.println("rline---------"+list.get(i));
			}
		} catch (FileNotFoundException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		/*FileReader f;
		try {
			f = new FileReader("f:/file/test.txt");
			LineNumberReader l=new LineNumberReader(f);
			String line;			
			while((line=l.readLine())!=null){
				if(l.getLineNumber()>=2 && l.getLineNumber()<=3){//输出2-3行			
					System.out.println(l.getLineNumber()+"."+line);
				}
			}		
		} catch (FileNotFoundException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}*/
		
	}

}

package com.stringtest;

import java.util.Arrays;
import java.util.Collection;
import java.util.Scanner;

public class InputNumber {

	public static void main(String[] args) {
		//接收5个整数，然后把这5个整数按照从小到大的顺序输出到屏幕上。
		/*System.out.println("请输入数字：");
		// 从键盘输入5个整数，并用空格分隔开
		Scanner input = new Scanner(System.in);
		String str = input.nextLine();
		String x[] = str.split(" "); // 使用split按空格分割，并赋值给数组x;		
		Arrays.sort(x);		//对输入的数排序（升序）
		//输出排序后的数到控制台
		for (int i = 0; i < x.length; i++)
			System.out.print(x[i] + "  ");*/
		
		//截取字符串并存入数组
		String str = "418,356,-121,-249,-355,382,1506490,520,601,-109,2047,1260,1150,1390,560950";		
		String[] ch= str.split(",");  //截取字符串
		for (int i = 0; i < ch.length; i++) {
			System.out.println(ch[i]);
		}
	}

}

import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;

public class DateFomatTest {

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		
		//日期转换为字符串型
	    SimpleDateFormat str = new SimpleDateFormat("yyyy-MM");
	    Date date = new Date();
	    String string = str.format(date);
	    System.out.println(string);
	    
	    //字符串型转换为日期
	    SimpleDateFormat sim=new SimpleDateFormat("yyyy-MM-dd hh:mm:ss");
		String str3="2011-5-31 14:40:50";
		try {
			Date d=sim.parse(str3);
			System.out.println("date------"+d);
		} catch (ParseException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}

	    
	    //拆分字符串
	    String strsp = "i?te|ye";	    
	    String[] str2 = strsp.split("\\?");	//一些特殊字符的拆分要用\\转义
	    for (int i = 0; i < str2.length; i++) {
	    	System.out.println(str2[i]);
		}
	    
	}

}

import java.io.*; 
//怎么改文件的后缀名，改一个文件夹下的所有的文件的后缀名，若有子文件夹，也都改了
public class ChangeFileName {
	
	public static void main(String[] args) {
	    String rootPath = "f:\\file"; // 搜索的根目录
	    changeExt(rootPath); 
		}
	
	public static void changeExt(String pathName) 
    { 
        File file = new File(pathName); 
        File[] files = file.listFiles(); 
        for (int i = 0; i < files.length; i++){ 
        	//测试此抽象路径名表示的文件是否是一个目录
            if (files[i].isDirectory()){
            	//返回此抽象路径名的绝对路径名字符串
                changeExt(files[i].getAbsolutePath()); 
            } 
            String name = files[i].getAbsolutePath();
            System.out.println(name);
            
            if (name.lastIndexOf(".txt") != -1)  { 
            	System.out.println("indexof------"+name.lastIndexOf(".txt"));
            	//重新命名此抽象路径名表示的文件，截取原文件名并加.zip后缀
                    boolean is = files[i].renameTo(new File(name.substring(0, name.lastIndexOf(".txt"))+ ".zip")); 
                    if (is){ 
                        System.out.println(files[i].getAbsolutePath()+ " changed to "+ name.substring(0, name.lastIndexOf(".txt")) + ".zip"); 
                    } else { 
                        System.out.println("Error happend!"); 
                    } 
            } 
        } 
    }	

}

/**
 * 一个画图程序 要求打印出 
Java代码  
int i=5;   
1  2  3  4  5  
16 17 18 19 6  
15 24 25 20 7  
14 23 22 21 8  
13 12 11 10 9  
  
int i=6  
1  2  3  4  5   6  
20 21 22 23 24  7  
19 32 33 34 25  8  
18 31 36 35 26  9  
17 30 29 28 27 10  
16 15 14 13 12 11  
 *
 */
public class ArrayTwo {
	
	public static void main(String[] args) {
		
		int N = 5;
		int a[][] = new int[N][N];
		int i = 0, j = 0;
		int count = 1;
		//把二维数组初始化为0
		for (i = 0; i < N; i++) {
			for (j = 0; j < N; j++) {
				a[i][j] = 0;
			}
		}
		i = 0;
		j = 0;
		//开始实现
		for (int k = 0; k <= N / 2; k++) {
			i = k;
			j = k;
			//第一行
			for (i = k; i < N - k; i++) {
				a[j][i] = count;
				count++;
			}
			//第五列
			i = N - k - 1;
			for (j = k + 1; j < N - k; j++) {
				a[j][i] = count;
				count++;
			}
			//第五行
			j = N - k - 1;
			for (i = N - k - 2; i >= k; i--) {
				a[j][i] = count;
				count++;
			}
			//第一列
			i = k;
			for (j = N - k - 2; j >= 1 + k; j--) {
				a[j][i] = count;
				count++;
			}
		}

		for (i = 0; i < N; i++) {
			for (j = 0; j < N; j++) {
				System.out.print(a[i][j] + " ");
			}
			System.out.println();
		}
	}

}