# 使用`BufferedWriter`，`PrintWriter`，`FileWriter`附加到 java 中的文件 > 原文： [https://beginnersbook.com/2014/01/how-to-append-to-a-file-in-java/](https://beginnersbook.com/2014/01/how-to-append-to-a-file-in-java/) 在本教程中，我们将学习如何使用 Java 将内容附加到文件中。有两种方法可以追加： 1）使用`FileWriter`和`BufferedWriter`：在这种方法中，我们将在一个或多个字符串中包含内容，我们将把这些字符串附加到文件中。该文件可以单独使用`FileWriter`附加，但使用`BufferedWriter`可以在维护缓冲区时提高性能。 2）使用`PrintWriter`：这是将内容附加到文件的最佳方式之一。无论你使用`PrintWriter`对象写什么都会附加到文件中。 ## 1）使用`FileWriter`和`BufferedWriter`将内容附加到`File` ```java import java.io.File; import java.io.FileWriter; import java.io.BufferedWriter; import java.io.IOException; class AppendFileDemo { public static void main( String[] args ) { try{ String content = "This is my content which would be appended " + "at the end of the specified file"; //Specify the file name and path here File file =new File("C://myfile.txt"); /* This logic is to create the file if the * file is not already present */ if(!file.exists()){ file.createNewFile(); } //Here true is to append the content to file FileWriter fw = new FileWriter(file,true); //BufferedWriter writer give better performance BufferedWriter bw = new BufferedWriter(fw); bw.write(content); //Closing BufferedWriter Stream bw.close(); System.out.println("Data successfully appended at the end of file"); }catch(IOException ioe){ System.out.println("Exception occurred:"); ioe.printStackTrace(); } } } ``` 输出： ```java Data successfully appended at the end of file ``` 让我们说`myfile.txt`的内容是： ```java This is the already present content of my file ``` 运行上述程序后，内容将是： ```java This is the already present content of my fileThis is my content which would be appended at the end of the specified file ``` ## 2）使用`PrintWriter`将内容附加到`File` `PrintWriter`为您提供更大的灵活性。使用此功能，您可以轻松格式化要附加到`File`的内容。 ```java import java.io.File; import java.io.FileWriter; import java.io.PrintWriter; import java.io.BufferedWriter; import java.io.IOException; class AppendFileDemo2 { public static void main( String[] args ) { try{ File file =new File("C://myfile.txt"); if(!file.exists()){ file.createNewFile(); } FileWriter fw = new FileWriter(file,true); BufferedWriter bw = new BufferedWriter(fw); PrintWriter pw = new PrintWriter(bw); //This will add a new line to the file content pw.println(""); /* Below three statements would add three * mentioned Strings to the file in new lines. */ pw.println("This is first line"); pw.println("This is the second line"); pw.println("This is third line"); pw.close(); System.out.println("Data successfully appended at the end of file"); }catch(IOException ioe){ System.out.println("Exception occurred:"); ioe.printStackTrace(); } } } ``` 输出： ```java Data successfully appended at the end of file ``` 让我们说`myfile.txt`的内容是： ```java This is the already present content of my file ``` 运行上述程序后，内容将是： ```java This is the already present content of my file This is first line This is the second line This is third line ``` #### 参考： * [`FileWriter` - JavaDoc](https://docs.oracle.com/javase/7/docs/api/java/io/FileWriter.html "FileWriter") * [`BufferedWriter` - JavaDoc](https://docs.oracle.com/javase/7/docs/api/java/io/BufferedWriter.html) * [`PrintWriter` - Javadoc](https://docs.oracle.com/javase/7/docs/api/java/io/PrintWriter.html "PrintWriter")