在 Java 中创建、编写和编辑相同的文本文件
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Creating, writing and editing same text file in java
提问by Vlad Dumitrache
Let's say I have the following code:
假设我有以下代码：
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
public class EditFile {
public static void main(String[] args) {
try{
String verify, putData;
File file = new File("file.txt");
file.createNewFile();
FileWriter fw = new FileWriter(file);
BufferedWriter bw = new BufferedWriter(fw);
bw.write("Some text here for a reason");
bw.flush();
bw.close();
FileReader fr = new FileReader(file);
BufferedReader br = new BufferedReader(fr);
while( br.readLine() != null ){
verify = br.readLine();
if(verify != null){
putData = verify.replaceAll("here", "there");
bw.write(putData);
}
}
br.close();
}catch(IOException e){
e.printStackTrace();
}
}
}
All I wanted to do was to write something in a text file, in my case "Some text here for a reason". Then to read data from my file, and finally to change my text from my file from "Some text here for a reason" in "Some text there for a reason". I ran the code but all it happens is to write in my file "Some text here for a reason".
我想要做的就是在文本文件中写一些东西，在我的例子中是“这里有一些文字是有原因的”。然后从我的文件中读取数据，最后将我的文件中的文本从“一些文本出于某种原因”更改为“一些文本出于某种原因”。我运行了代码，但发生的一切只是在我的文件中写下“这里有一些文字是有原因的”。
I tried to figure out what could be wrong in my code, but unfortunately it was in vain. Any advice or rewrite is highly appreciated from me.
我试图找出我的代码中可能有什么问题，但不幸的是它是徒劳的。我非常感谢任何建议或重写。
采纳答案by Yehia Awad
Change your code to that:
将您的代码更改为：
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
public class EditFile {
public static void main(String[] args) {
try{
String verify, putData;
File file = new File("file.txt");
file.createNewFile();
FileWriter fw = new FileWriter(file);
BufferedWriter bw = new BufferedWriter(fw);
bw.write("Some text here for a reason");
bw.flush();
bw.close();
FileReader fr = new FileReader(file);
BufferedReader br = new BufferedReader(fr);
while( (verify=br.readLine()) != null ){ //***editted
//**deleted**verify = br.readLine();**
if(verify != null){ //***edited
putData = verify.replaceAll("here", "there");
bw.write(putData);
}
}
br.close();
}catch(IOException e){
e.printStackTrace();
}
}
}
The Problem is that you are calling br.readLine()twice which is provoking the application to read line1 and then line2 and in your case you have just one line which means that your program read it in the conditional form and when it comes to declaring it to the variable verify, it is stopping because you don't have anymore data to read your file.
问题是您调用了br.readLine()两次，这促使应用程序读取 line1 和 line2，在您的情况下，您只有一行，这意味着您的程序以条件形式读取它，并在将其声明为变量时verify，它正在停止，因为您没有更多的数据来读取您的文件。
回答by Bhanupriya
I would do it this way:
我会这样做：
import java.io.*;
public class EditFile {
public static void main(String[] args) {
try{
String verify, putData;
File file = new File("file.txt");
file.createNewFile();
FileWriter fw = new FileWriter(file);
BufferedWriter bw = new BufferedWriter(fw);
bw.write("Some text here for a reason");
bw.flush();
FileReader fr = new FileReader(file);
BufferedReader br = new BufferedReader(fr);
while( (verify=br.readLine()) != null )
{
if(verify != null)
{
putData = verify.replaceAll("here", "there");
bw.write(putData);
}
}
br.close();
bw.close();
}catch(IOException e){
e.printStackTrace();
}
}
}
回答by shiv
use this code, I used it to remove logs and System.out statements in java file. just change the matching and replacing string.
使用此代码，我用它来删除 java 文件中的日志和 System.out 语句。只需更改匹配和替换字符串。
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileReader;
import java.io.FileWriter;
import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;
public class FileReplace {
List<String> lines = new ArrayList<String>();
String line = null;
Scanner scan = null;
public void doIt() {
scan = new Scanner(System.in);
while (true) {
try {
System.out
.println("enter qualified file name ex.D:\shiv\shiv android all\Main work space\Welcomescreen1.java");
String path = scan.nextLine();
File f1 = new File(path);
FileReader fr = new FileReader(f1);
BufferedReader br = new BufferedReader(fr);
int i = 0;
while ((line = br.readLine()) != null) {
if (line.contains("System.out")) {
line = line.replace("System.out", "//");
} else if (line.contains("Log.")) {
line = line.replace("Log", "//");
}
lines.add(i, line);
i++;
}
fr.close();
br.close();
FileWriter fw = new FileWriter(f1);
BufferedWriter out = new BufferedWriter(fw);
for (int j = 0; j < lines.size(); j++) {
System.out.println(j + "." + lines.get(j));
out.append(lines.get(j));
out.newLine();
}
out.flush();
out.close();
System.out
.println("====================work done===================");
} catch (Exception ex) {
ex.printStackTrace();
}
}
}
public static void main(String args[]) {
FileReplace fr = new FileReplace();
fr.doIt();
}
}
回答by Chanthu
File file = new File("/tmp/my.txt");
FileWriter fw;
BufferedReader br;
BufferedWriter bw;
boolean no=false;
String line;
String data="";
String lessonPath="my new line";
try {
if(!file.exists()){
fw = new FileWriter(file);
bw = new BufferedWriter(fw);
bw.write(lessonPath);
bw.flush();
bw.close();
}else{
br = new BufferedReader(new FileReader(file));
while((line =br.readLine()) !=null){
if(!no){
data=line;
no=true;
}else{
data = data+"\n"+line;
}
}
bw = new BufferedWriter(new FileWriter(file));
bw.write(data+"\n"+lessonPath);
bw.flush();
bw.close();
}
} catch (Exception ex) {
ex.printStackTrace();
}
回答by Shah Khalid
import java.io.*;
public class TextFile
{
public static void main(String[] args)
{
try
{
String verify, putData;
File file = new File("G:\Dairy.txt");
file.createNewFile();
FileWriter fw = new FileWriter(file);
BufferedWriter bw = new BufferedWriter(fw);
bw.write("I am Shah Khalid");
bw.flush();
FileReader fr = new FileReader(file);
BufferedReader br = new BufferedReader(fr);
while( (verify=br.readLine()) != null )
{
if(verify != null)
{
putData = verify.replaceAll("here", "there");
//bw.write(putData);
}
}
br.close();
bw.close();
}
catch(IOException e)
{
e.printStackTrace();
}
System.out.println("Shah");
}
}
There is no need to type bw.write(putData);, because it will just print the statement twice.
Whatever you want in a file, just give the correct path of the file and use the above code accordingly.
不需要输入bw.write(putData);，因为它只会打印两次语句。
无论你想要什么文件，只要给出文件的正确路径并相应地使用上面的代码。
