[英]Java read from one file and write into another file using methods
我正在学习Java并从事文件IO工作,现在正忙于从一个文件中读取文本并写入另一个文件。 我使用两种不同的方法,首先用于从文件#1读取和显示控制台中的文本,并使用另一种方法在文件#2中写入。
我可以成功读取和显示文件#1中的内容,但不知道如何在文件#2中写入文本。
这是我到目前为止编写的代码:
import java.io.*;
public class ReadnWrite {
public static void readFile() throws IOException {
BufferedReader inputStream = new BufferedReader(new FileReader(
"original.txt"));
String count;
while ((count = inputStream.readLine()) != null) {
System.out.println(count);
}
inputStream.close();
}
public static void writeFile() throws IOException{
BufferedWriter outputStream = new BufferedWriter(new FileWriter(
"numbers.txt"));
//Not sure what comes here
}
public static void main(String[] args) throws IOException {
checkFileExists();
readFile();
}
}
这仅仅是为了我自己的学习,因为有许多例子可以在不使用不同方法的情况下进行读写,但我希望能够通过不同的方法实现。
任何帮助将受到高度赞赏。
问候,
您可以使用: outputStream.write()
写入另一个文件。 当你完成后只需输出outputStream.flush()
和outputStream.close()
。
编辑:
public void readAndWriteFromfile() throws IOException {
BufferedReader inputStream = new BufferedReader(new FileReader(
"original.txt"));
File UIFile = new File("numbers.txt");
// if File doesnt exists, then create it
if (!UIFile.exists()) {
UIFile.createNewFile();
}
FileWriter filewriter = new FileWriter(UIFile.getAbsoluteFile());
BufferedWriter outputStream= new BufferedWriter(filewriter);
String count;
while ((count = inputStream.readLine()) != null) {
outputStream.write(count);
}
outputStream.flush();
outputStream.close();
inputStream.close();
这是我如何复制文件的方式:
BufferedReader br = null;
BufferedWriter bw = null;
try {
br = new BufferedReader(new InputStreamReader(new FileInputStream(new File("origin.txt"))));
bw = new BufferedWriter(new OutputStreamWriter(new FileOutputStream(new File("target.txt"))));
int i;
do {
i = br.read();
if (i != -1) {
bw.write(i);
}
} while (i != -1);
} catch (IOException e) {
System.err.println("error during copying: "+ e.getMessage());
} finally {
try {
if (br != null) br.close();
if (bw != null) bw.close();
} catch (IOException e) {
System.err.println("error during closing: "+ e.getMessage());
}
}
我会使用一个BufferedReader
是包装了FileReader
和BufferedWriter
一个包装了FileWriter
。
由于您希望使用两种不同的方法来执行此操作,因此必须将数据存储在List<String> data
以在方法之间传递List<String> data
。
public class ReadnWrite {
public static List<String> readFile() throws IOException {
try(BufferedReader br = new BufferedReader(new FileReader("original.txt"))){
List<String> listOfData = new ArrayList<>();
String d;
while((d = br.readLine()) != null){
listOfData.add(d);
}
return listOfData;
}
}
public static void writeFile(List<String> listOfData) throws IOException{
try(BufferedWriter bw = new BufferedWriter(new FileWriter("numbers.txt"))){
for(String str: listOfData){
bw.write(str);
bw.newLine();
}
}
}
public static void main(String[] args) throws IOException {
List<String> data = readFile();
writeFile(data);
}
}
作为替代方案,如果您不必在读取和写入之间对数据进行操作,我也会在一种方法中执行此操作。
public class CopyFileBufferedRW {
public static void main(String[] args) {
File originalFile = new File("original.txt");
File newFile = new File(originalFile.getParent(), "numbers.txt");
try (BufferedReader br = new BufferedReader(new FileReader(originalFile));
BufferedWriter bw = new BufferedWriter(new FileWriter(newFile))) {
String s;
while ((s = br.readLine()) != null) {
bw.write(s);
bw.newLine();
}
} catch (IOException e) {
System.err.println("error during copying: " + e.getMessage());
}
}
}
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