如果出于某种原因想要将创建和编写行为分开，那么Java中的touch等价物是

try {
   //create a file named "testfile.txt" in the current working directory
   File myFile = new File("testfile.txt");
   if ( myFile.createNewFile() ) {
      System.out.println("Success!");
   } else {
      System.out.println("Failure!");
   }
} catch ( IOException ioe ) { ioe.printStackTrace(); }

createNewFile（）执行存在性检查，并自动创建文件。例如，如果您希望在写入文件之前确保自己是文件的创建者，这可能很有用。

这里有一个创建或覆盖文件的小示例程序。这是一个长版本，因此可以更容易理解。

import java.io.BufferedWriter;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStreamWriter;
import java.io.Writer;

public class writer {
    public void writing() {
        try {
            //Whatever the file path is.
            File statText = new File("E:/Java/Reference/bin/images/statsTest.txt");
            FileOutputStream is = new FileOutputStream(statText);
            OutputStreamWriter osw = new OutputStreamWriter(is);    
            Writer w = new BufferedWriter(osw);
            w.write("POTATO!!!");
            w.close();
        } catch (IOException e) {
            System.err.println("Problem writing to the file statsTest.txt");
        }
    }

    public static void main(String[]args) {
        writer write = new writer();
        write.writing();
    }
}

最好的方法是使用Java7：Java7引入了一种处理文件系统的新方法，以及一个新的实用程序类—Files。使用Files类，我们还可以创建、移动、复制、删除文件和目录；它还可以用于读取和写入文件。

public void saveDataInFile(String data) throws IOException {
    Path path = Paths.get(fileName);
    byte[] strToBytes = data.getBytes();

    Files.write(path, strToBytes);
}

使用FileChannel写入如果您正在处理大型文件，FileChannel可以比标准IO更快。以下代码使用FileChannel将字符串写入文件：

public void saveDataInFile(String data) 
  throws IOException {
    RandomAccessFile stream = new RandomAccessFile(fileName, "rw");
    FileChannel channel = stream.getChannel();
    byte[] strBytes = data.getBytes();
    ByteBuffer buffer = ByteBuffer.allocate(strBytes.length);
    buffer.put(strBytes);
    buffer.flip();
    channel.write(buffer);
    stream.close();
    channel.close();
}

使用DataOutputStream写入

public void saveDataInFile(String data) throws IOException {
    FileOutputStream fos = new FileOutputStream(fileName);
    DataOutputStream outStream = new DataOutputStream(new BufferedOutputStream(fos));
    outStream.writeUTF(data);
    outStream.close();
}

使用FileOutputStream写入

现在让我们看看如何使用FileOutputStream将二进制数据写入文件。以下代码转换String int字节，并使用FileOutputStream将字节写入文件：

public void saveDataInFile(String data) throws IOException {
    FileOutputStream outputStream = new FileOutputStream(fileName);
    byte[] strToBytes = data.getBytes();
    outputStream.write(strToBytes);

    outputStream.close();
}

使用PrintWriter写入我们可以使用PrintWriter将格式化文本写入文件：

public void saveDataInFile() throws IOException {
    FileWriter fileWriter = new FileWriter(fileName);
    PrintWriter printWriter = new PrintWriter(fileWriter);
    printWriter.print("Some String");
    printWriter.printf("Product name is %s and its price is %d $", "iPhone", 1000);
    printWriter.close();
}

使用BufferedWriter写入：使用BufferedWriter将字符串写入新文件：

public void saveDataInFile(String data) throws IOException {
    BufferedWriter writer = new BufferedWriter(new FileWriter(fileName));
    writer.write(data);

    writer.close();
}

将字符串附加到现有文件：

public void saveDataInFile(String data) throws IOException {
    BufferedWriter writer = new BufferedWriter(new FileWriter(fileName, true));
    writer.append(' ');
    writer.append(data);

    writer.close();
}

如果出于某种原因想要将创建和编写行为分开，那么Java中的touch等价物是

try {
   //create a file named "testfile.txt" in the current working directory
   File myFile = new File("testfile.txt");
   if ( myFile.createNewFile() ) {
      System.out.println("Success!");
   } else {
      System.out.println("Failure!");
   }
} catch ( IOException ioe ) { ioe.printStackTrace(); }

createNewFile（）执行存在性检查，并自动创建文件。例如，如果您希望在写入文件之前确保自己是文件的创建者，这可能很有用。

有一些简单的方法，例如：

File file = new File("filename.txt");
PrintWriter pw = new PrintWriter(file);

pw.write("The world I'm coming");
pw.close();

String write = "Hello World!";

FileWriter fw = new FileWriter(file);
BufferedWriter bw = new BufferedWriter(fw);

fw.write(write);

fw.close();

使用JFilechooser与客户一起阅读集合并保存到文件。

private void writeFile(){

    JFileChooser fileChooser = new JFileChooser(this.PATH);
    int retValue = fileChooser.showDialog(this, "Save File");

    if (retValue == JFileChooser.APPROVE_OPTION){

        try (Writer fileWrite = new BufferedWriter(new OutputStreamWriter(new FileOutputStream(fileChooser.getSelectedFile())))){

            this.customers.forEach((c) ->{
                try{
                    fileWrite.append(c.toString()).append("\n");
                }
                catch (IOException ex){
                    ex.printStackTrace();
                }
            });
        }
        catch (IOException e){
            e.printStackTrace();
        }
    }
}