Java 如何覆盖文本文件中的一行?
我想知道如何在我的文本文件中覆盖一行代码,我正在创建高分,我想知道如何覆盖代码行以更改所有分数的最高难度评级。现在我正在使用bufferedWriter;但它不会覆盖以前的分数Java 如何覆盖文本文件中的一行?,java,Java,我想知道如何在我的文本文件中覆盖一行代码,我正在创建高分,我想知道如何覆盖代码行以更改所有分数的最高难度评级。现在我正在使用bufferedWriter;但它不会覆盖以前的分数 String timeStamp = new SimpleDateFormat("HH:mm MM/dd/yyyy").format(Calendar.getInstance().getTime());//gets time to say when the score was made FileWriter fileWr
String timeStamp = new SimpleDateFormat("HH:mm MM/dd/yyyy").format(Calendar.getInstance().getTime());//gets time to say when the score was made
FileWriter fileWriter;
double difficultyRating;
BufferedWriter bufferedWriter;
public void printHighScores(String p1Name, long elapsedTime, int boardWidth, int boardLength, int mines, boolean avoidDoublePrint, File highScores){
//writes to a file their score
try{
//stops error where it would print multiple times on file
if(avoidDoublePrint){
fileWriter = new FileWriter(highScores, true);//creates a writer to write in file highScores
bufferedWriter = new BufferedWriter(fileWriter);//also makes it so to write in
double bw=(double) boardWidth;
double bl=(double) boardLength;
double ms=(double) mines;
difficultyRating = ms/(bl*bw)*100;//finds the difficulty rating on a scale of 1-10 based on mines per square
DecimalFormat dec = new DecimalFormat("#.##");//formats to 2 decimals
bufferedWriter.write(""+p1Name+": "+elapsedTime+" Second(s) on a ("+boardWidth+" X "+boardLength+") grid with "+mines+" Mine(s) DR: "+dec.format(difficultyRating)+"%");//writes this to file
bufferedWriter.newLine();
bufferedWriter.write(timeStamp);
bufferedWriter.newLine();
bufferedWriter.newLine();
bufferedWriter.close();//closes writing in file
System.out.println("Done");//for testing
avoidDoublePrint=false;//make it so that it will not print twice, as it ends the if statement
}
}catch (Exception e){//if an error occurs
System.out.println("Error because of high score printing");
}//end of catch
try {
BufferedReader br = new BufferedReader(new FileReader("highScores.txt"));
String line = br.readLine();
while (line != null) {
for(int i = 0; i < 30; ++i){
br.readLine();
if(i==3){
line = br.readLine();
double highest = Double.valueOf(line);
System.out.println(highest);
System.out.println(difficultyRating);
if(difficultyRating>highest){
bufferedWriter.write(""+difficultyRating+"");
}
}
}
}
br.close();
} catch(Exception e){
}
}//end of print high scores
String timeStamp=new-SimpleDateFormat(“HH:mm-mm/dd/yyyy”).format(Calendar.getInstance().getTime())//有时间说什么时候得分
文件编写器文件编写器;
双重困难;
缓冲写入程序缓冲写入程序;
public void printHighScores(字符串p1Name、长elapsedTime、int boardWidth、int boardLength、int mines、boolean avoidDoublePrint、文件highScores){
//将他们的分数写入文件
试一试{
//停止将在文件上多次打印的错误
如果(避免双重打印){
fileWriter=newfilewriter(highScores,true);//创建一个writer以写入文件highScores
bufferedWriter=new bufferedWriter(fileWriter);//也可以这样写
双bw=(双)板宽;
双bl=(双)板长;
双ms=(双)地雷;
难度等级=ms/(bl*bw)*100;//根据每平方米的地雷数,在1-10的范围内找到难度等级
DecimalFormat dec=新的DecimalFormat(“#.####”);//格式为2个小数
bufferedWriter.write(“+p1Name+”:“+elapsedTime+”秒)在(“+boardWidth+”X“+boardLength+”)网格上,使用“+mines+”Mine(s)DR:“+dec.format(Hardicultyrating)+”%”;//将其写入文件
bufferedWriter.newLine();
bufferedWriter.write(时间戳);
bufferedWriter.newLine();
bufferedWriter.newLine();
bufferedWriter.close();//关闭文件写入
System.out.println(“完成”);//用于测试
avoidDoublePrint=false;//使其在结束if语句时不会打印两次
}
}捕获(异常e){//如果发生错误
System.out.println(“由于高分打印导致的错误”);
}//捕获结束
试一试{
BufferedReader br=新的BufferedReader(新的文件阅读器(“highScores.txt”);
String line=br.readLine();
while(行!=null){
对于(int i=0;i<30;++i){
br.readLine();
如果(i==3){
line=br.readLine();
最高两倍=最高两倍的值(行);
系统输出打印项次(最高);
系统输出打印LN(打印困难);
如果(难度>最高){
bufferedWriter.write(“+难处理+”);
}
}
}
}
br.close();
}捕获(例外e){
}
}//打印结束高分
}您说要覆盖文件中的一行,但我看不到您将光标或其他任何内容放在何处 在您的问题下的评论中提到的方法应该是正确的:
bufferedWriter.write(""+p1Name+": "+elapsedTime+" Second(s) on a ("+boardWidth+" X "+boardLength+") grid with "+mines+" Mine(s) DR: "+dec.format(difficultyRating)+"%");
您想如何确定现在必须更换哪一行
我建议您以CSV格式管理您的高分,这样您就可以轻松地选择任何值来做任何您想用它做的事情:
玩家名称;时间董事会;等
也许这可以帮助: 示例文本文件:
John : 1000 Second(s) on a (100X100) grid with 2 Mine(s) DR: 10.00%
06:34:23
private static void ReplaceSingleLine(string path, string find, string replace)
{
IEnumerable<string> n = File.ReadAllLines(path).Select(line => System.Text.RegularExpressions.Regex.Replace(line, find, replace));
File.WriteAllLines(path, n);
}
static void Main(string[] args)
{
string _path = Path.GetDirectoryName(Environment.GetCommandLineArgs()[0]);
ReplaceSingleLine(_path + "\\test.txt", "DR: .*%", "DR: 25.5%");
}
(2排)
功能:
John : 1000 Second(s) on a (100X100) grid with 2 Mine(s) DR: 10.00%
06:34:23
private static void ReplaceSingleLine(string path, string find, string replace)
{
IEnumerable<string> n = File.ReadAllLines(path).Select(line => System.Text.RegularExpressions.Regex.Replace(line, find, replace));
File.WriteAllLines(path, n);
}
static void Main(string[] args)
{
string _path = Path.GetDirectoryName(Environment.GetCommandLineArgs()[0]);
ReplaceSingleLine(_path + "\\test.txt", "DR: .*%", "DR: 25.5%");
}
“DR:.*%”
要从DR:10.00%
更改为DR:25.5%
请说明您正在尝试做什么。您想覆盖某一特定位置的一行还是最后写入的一行?基本上,您需要读取整个文件并替换所需的行,然后重新写入。现在你可以“聪明”并在阅读旧文件时将内容写入新文件,更新需要更新的行,删除旧文件并将新文件重命名到原来的位置…特洛伊木马,我正在尝试在特定位置覆盖