文件操作与java正则练习

/**
* 从一个文本文件中读入字符串，然后把该字符串写入另一个文本中
*/

package practice;

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class RegexFile {
private String fileName = "e://test.txt";        //要读的文件
private String date;

//读文件
public void readFile() {
Pattern p = Pattern
.compile("//w*[ *]//w*.*//d[ *]//d{2}[:]//d{2}[:]//d{2}[ *]//d{4}");        //匹配格式形如X X  X X:XX:XX XXXX的正则表达式
BufferedReader reader = null;

try {
reader = new BufferedReader(new FileReader(fileName));
String line = null;
while ((line = reader.readLine()) != null) {
Matcher m = p.matcher(line);
if (m.find()) {
date = m.group();
}
}
System.out.println(date);
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} finally {
if (reader != null)
try {
reader.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}

//写文件
public void writeTxt() {
File file = new File("E://test2.txt");    //要写入的文件
BufferedWriter writer = null;
try {
if (!file.exists())
file.createNewFile();

writer = new BufferedWriter(new FileWriter(file));
writer.write(date);
} catch (IOException e) {
e.printStackTrace();
} finally {
if (writer != null)
try {
writer.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}

public static void main(String[] args) {
RegexFile regexFile = new RegexFile();
regexFile.readFile();
regexFile.writeTxt();
}
}