java 文件内容中的java正则表达式
声明：本页面是StackOverFlow热门问题的中英对照翻译，遵循CC BY-SA 4.0协议，如果您需要使用它，必须同样遵循CC BY-SA许可，注明原文地址和作者信息，同时你必须将它归于原作者（不是我）：StackOverFlow
原文地址: http://stackoverflow.com/questions/11877232/
Warning: these are provided under cc-by-sa 4.0 license. You are free to use/share it, But you must attribute it to the original authors (not me):
StackOverFlow
java regular expression in a file content
提问by Varaprasad B
How to use regular expressions in a file content. i am having group of files, i want to search a string in all the files and replace in all the files.
如何在文件内容中使用正则表达式。我有一组文件，我想在所有文件中搜索一个字符串并替换所有文件。
can anybody help me in this? the cose is below:
有人可以帮我吗？成本如下：
package com.java.far;
import java.io.*;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
public class ReplaceAll {
public static void main(String[] args)throws IOException {
Runtime r=Runtime.getRuntime();
System.out.println(r.freeMemory());
String path="D:\JOBRELATED\FAR";
String files;
File folder=new File(path);
File[] listofFiles=folder.listFiles();
for (int i = 0; i < listofFiles.length; i++) {
if (listofFiles[i].isFile()) {
files=listofFiles[i].getName();
if(files.endsWith("tex")){
System.out.println(files);
BufferedReader br=new BufferedReader(new FileReader("D:\JOBRELATED\FAR\"+files));
String line;
while((line=br.readLine())!=null){
Pattern p=Pattern.compile("Diamond in History and Research");
Matcher m=p.matcher(line);
int count=0;
while (m.find()) {
count++;
//System.out.println(m.start() +"\t"+ count);
System.out.println(line);
m.replaceAll("abc");
}
}
}
}
}
}
}
回答by Teh Hippo
Looks like you're on the right track; I don't know of a framework that will find & replace within a file. I have put some other tips below which you could review.
看起来你走在正确的轨道上；我不知道可以在文件中查找和替换的框架。我在下面列出了一些其他提示，您可以查看这些提示。
Your final step which you're missing is to add a OutputWriter, or similar outputter. Once you've read the file contents, check it contains the match & replaced it, you should do a boolean check whether a change was made. If so, output the file.
您缺少的最后一步是添加一个 OutputWriter 或类似的输出器。阅读文件内容后，检查它是否包含匹配项并替换它，您应该进行布尔值检查是否进行了更改。如果是，输出文件。
Other comments:
1. You won't need to do a listofFiles[i].isFile()if you're using .listFiles()2. Compile your pattern outside of the forloop for efficiency.
3. Use a dynamic for loop, might make it easier: for(final File file : listofFiles)
其他评论： 1.listofFiles[i].isFile()如果您正在使用，则不需要执行.listFiles()2. 在for循环之外编译模式以提高效率。3.使用动态for循环，可能会更容易：for(final File file : listofFiles)
Example:
例子：
final File[] files = new File(".").listFiles();
final Pattern pattern = Pattern.compile(".*a.*");
for(final File file : files) {
System.out.println(file.getName());
final BufferedReader reader = new BufferedReader(new FileReader(file));
final StringBuilder contents = new StringBuilder();
while(reader.ready()) {
contents.append(reader.readLine());
}
reader.close();
final String stringContents = contents.toString();
if(stringContents.toString().matches(".*a.*")) {
stringContents.replaceAll("a", "b");
final BufferedWriter writer = new BufferedWriter(new FileWriter(file));
writer.write(stringContents);
writer.close();
}
}
