个人博客 地址:http://www.wenhaofan.com/article/20180913160442

代码如下package com.wenhaofan.common.kit;

import java.io.BufferedReader;

import java.io.File;

import java.io.FileInputStream;

import java.io.FileOutputStream;

import java.io.IOException;

import java.io.InputStreamReader;

import java.io.PrintWriter;

import com.jfinal.kit.PropKit;

/**

* @author 作者:范文皓

* @createDate 创建时间：2018年9月13日 下午3:59:07

*/

public class PropertyKit {

public static void main(String[] args) {

String path=FileKit.class.getResource("/blog_config.txt").getPath() ;

path=path.substring(1, path.length());

replace(path,"theme","newTheme");

String theme=PropKit.use("blog_config.txt").get("theme");

System.out.println(theme);

}

public static void replace(String path,String key,String newValue) {

String temp = "";

try {

File file = new File(path);

FileInputStream fis = new FileInputStream(file);

InputStreamReader isr = new InputStreamReader(fis);

BufferedReader br = new BufferedReader(isr);

StringBuffer buf = new StringBuffer();

// 保存该行前面的内容

while ( (temp = br.readLine()) != null) {

boolean isMath=StrKit.filterNull(temp).split("=")[0].equals(key);

if(isMath){

buf = buf.append(key+"="+newValue);

}else{

buf = buf.append(temp);

}

buf = buf.append(System.getProperty("line.separator"));

}

br.close();

FileOutputStream fos = new FileOutputStream(file);

PrintWriter pw = new PrintWriter(fos);

pw.write(buf.toString().toCharArray());

pw.flush();

pw.close();

} catch (IOException e) {

e.printStackTrace();

}

}

}

实现思路

按行读取指定文本中的内容，将内容添加进StringBuffer中,

如果当前行号为指定行号则添加替换的内容，否则添加原内容

然后将StringBuffer中的内容覆盖写入文件