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();

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();
    }
}

public class Program {
    public static void main(String[] args) {
        String text = "Hello world";
        BufferedWriter output = null;
        try {
            File file = new File("example.txt");
            output = new BufferedWriter(new FileWriter(file));
            output.write(text);
        } catch ( IOException e ) {
            e.printStackTrace();
        } finally {
          if ( output != null ) {
            try {
                output.close();
            }catch (IOException e){
                e.printStackTrace();
            }
          }
        }
    }
}

在Java 11+中，编写纯文本：

Files.writeString(Path.of("filename.txt"), "some-text");

在Java 7及以上版本中：

try (Writer writer = new BufferedWriter(new OutputStreamWriter(
              new FileOutputStream("filename.txt"), "utf-8"))) {
   writer.write("something");
}

但有一些有用的实用程序：

来自commons io的FileUtils.writeStringtoFile（..）来自番石榴的文件.write（..）

还要注意，您可以使用FileWriter，但它使用默认编码，这通常是一个坏主意-最好显式指定编码。

以下是Java 7之前的原始答案

Writer writer = null;

try {
    writer = new BufferedWriter(new OutputStreamWriter(
          new FileOutputStream("filename.txt"), "utf-8"));
    writer.write("Something");
} catch (IOException ex) {
    // Report
} finally {
   try {writer.close();} catch (Exception ex) {/*ignore*/}
}

另请参阅：读取、写入和创建文件（包括NIO2）。

创建示例文件：

try {
    File file = new File ("c:/new-file.txt");
    if(file.createNewFile()) {
        System.out.println("Successful created!");
    }
    else {
        System.out.println("Failed to create!");
    }
}
catch (IOException e) {
    e.printStackTrace();
}