用Java创建和写入(文本)文件的最简单方法是什么?


当前回答

package fileoperations;
import java.io.File;
import java.io.IOException;

public class SimpleFile {
    public static void main(String[] args) throws IOException {
        File file =new File("text.txt");
        file.createNewFile();
        System.out.println("File is created");
        FileWriter writer = new FileWriter(file);

        // Writes the content to the file
        writer.write("Enter the text that you want to write"); 
        writer.flush();
        writer.close();
        System.out.println("Data is entered into file");
    }
}

其他回答

如果您希望获得相对轻松的体验,还可以查看Apache Commons IO包,更具体地说是FileUtils类。

永远不要忘记检查第三方库。用于日期操作的Joda Time、用于常见字符串操作的Apache Commons Lang StringUtils等可以使代码更可读。

Java是一种很棒的语言,但标准库有时有点低级。功能强大,但级别较低。

请注意,下面的每个代码示例都可能引发IOException。为了简洁起见,省略了Try/catch/finally块。有关异常处理的信息,请参阅本教程。

请注意,如果文件已经存在,下面的每个代码示例都将覆盖该文件

创建文本文件:

PrintWriter writer = new PrintWriter("the-file-name.txt", "UTF-8");
writer.println("The first line");
writer.println("The second line");
writer.close();

创建二进制文件:

byte data[] = ...
FileOutputStream out = new FileOutputStream("the-file-name");
out.write(data);
out.close();

Java 7+用户可以使用Files类写入文件:

创建文本文件:

List<String> lines = Arrays.asList("The first line", "The second line");
Path file = Paths.get("the-file-name.txt");
Files.write(file, lines, StandardCharsets.UTF_8);
//Files.write(file, lines, StandardCharsets.UTF_8, StandardOpenOption.APPEND);

创建二进制文件:

byte data[] = ...
Path file = Paths.get("the-file-name");
Files.write(file, data);
//Files.write(file, data, StandardOpenOption.APPEND);

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();
    }
}

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();

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。