今天同事的一个问题,我写了个demo,替换掉文本中的满足IP格式的字符串,替换成需要更改的。
IP格式没有严格写,简单弄个demo。这个可以演变成查询日志,替换或者标红关键字等。
对于其中的正则等java类可参看http://www.cnblogs.com/playing/archive/2011/03/15/1984943.html
import java.io.BufferedReader; import java.io.BufferedWriter; import java.io.FileInputStream; import java.io.FileOutputStream; import java.io.IOException; import java.io.InputStreamReader; import java.io.OutputStreamWriter; import java.util.regex.Matcher; import java.util.regex.Pattern; public class TestFile { static final String REGEX_IPV4 = "(\\d{1,3}\\.){3}\\d{1,3}"; static final String ENCODE = "UTF-8"; BufferedReader br = null; BufferedWriter bw = null; public void copyFile(String ip) throws IOException { try { Pattern pattern = Pattern.compile(REGEX_IPV4); br = new BufferedReader(new InputStreamReader(new FileInputStream( "d:/A.txt"), ENCODE)); bw = new BufferedWriter(new OutputStreamWriter( new FileOutputStream("d:/B.txt"))); String line = null; while ((line = br.readLine()) != null) { StringBuffer sbr = new StringBuffer(); Matcher matcher = pattern.matcher(line); while (matcher.find()) { // 有字符串fatcatfatcatfat,假设既有正则表达式模式为"cat",第一次匹配后调用appendReplacement(sb,"dog"),那么这时StringBuffer // sb的内容为fatdog,也就是fatcat中的cat被替换为dog并且与匹配子串前的内容加到sb里,而第二次匹配后调用appendReplacement(sb,"dog"),那么sb的内容就变为fatdogfatdog,如果最后再调用一次appendTail(sb),那么sb最终的内容将是fatdogfatdogfat。 matcher.appendReplacement(sbr, ip); } // 将最后一次匹配工作后剩余的字符串添加到一个StringBuffer对象里 matcher.appendTail(sbr); bw.write(sbr.toString()); bw.newLine(); } } catch (IOException e) { } finally { bw.close(); br.close(); } } public static void main(String[] args) throws IOException { new TestFile().copyFile("255.255.255.0"); } }