如何使用Java将String保存到文本文件？

Question

在Java中,我有一个名为"text"的String变量中的文本字段的文本.

如何将"text"变量的内容保存到文件中？

Answer 1

如果您只是输出文本而不是任何二进制数据,则以下内容将起作用:

PrintWriter out = new PrintWriter("filename.txt");

然后,将String写入它,就像您对任何输出流一样:

out.println(text);

你需要像往常一样处理异常处理.out.close()写完后一定要打电话.

如果您使用的是Java 7或更高版本,则可以使用" try-with-resources语句 ",它将PrintStream在您完成时自动关闭(即退出块),如下所示:

try (PrintWriter out = new PrintWriter("filename.txt")) {
    out.println(text);
}

您仍然需要java.io.FileNotFoundException像以前一样显式抛出.

Answer 2

Apache Commons IO包含一些很好的方法,特别是FileUtils包含以下方法:

static void writeStringToFile(File file, String data) 

它允许您在一个方法调用中将文本写入文件:

FileUtils.writeStringToFile(new File("test.txt"), "Hello File");

您可能还需要考虑指定文件的编码.

Answer 3

看一下Java File API

一个简单的例子:

try (PrintStream out = new PrintStream(new FileOutputStream("filename.txt"))) {
    out.print(text);
}

Answer 4

刚刚在我的项目中做了类似的事情.使用FileWriter将简化部分工作.在这里你可以找到很好的教程.

BufferedWriter writer = null;
try
{
    writer = new BufferedWriter( new FileWriter( yourfilename));
    writer.write( yourstring);

}
catch ( IOException e)
{
}
finally
{
    try
    {
        if ( writer != null)
        writer.close( );
    }
    catch ( IOException e)
    {
    }
}

Answer 5

在Java 7中,您可以这样做:

String content = "Hello File!";
String path = "C:/a.txt";
Files.write( Paths.get(path), content.getBytes());

这里有更多信息:http: //www.drdobbs.com/jvm/java-se-7-new-file-io/231600403

Answer 6

使用FileUtils.writeStringToFile()来自Apache的百科全书IO.无需重新发明这个特殊的轮子.

Answer 7

您可以使用修改下面的代码从处理文本的任何类或函数中编写您的文件.人们想知道为什么世界需要一个新的文本编辑器......

import java.io.*;

public class Main {

    public static void main(String[] args) {

        try {
            String str = "SomeMoreTextIsHere";
            File newTextFile = new File("C:/thetextfile.txt");

            FileWriter fw = new FileWriter(newTextFile);
            fw.write(str);
            fw.close();

        } catch (IOException iox) {
            //do stuff with exception
            iox.printStackTrace();
        }
    }
}

Answer 8

在Java 11中,java.nio.file.Files类通过两个新的实用程序方法进行了扩展,将字符串写入文件(请参阅此处和此处的 JavaDoc ).在最简单的情况下,它现在是一个单行:

Files.writeString(Path.of("my", "path"), "My String");

使用可选的Varargs参数,可以设置其他选项,例如附加到现有文件或自动创建不存在的文件(请参阅此处的 JavaDoc ).

Answer 9

我希望尽可能依赖库来进行这种操作.这使我不太可能意外地省略了一个重要的步骤(如上面的错误狼人).上面提到了一些库,但我最喜欢的是Google Guava.Guava有一个名为Files的类,可以很好地完成这项任务:

// This is where the file goes.
File destination = new File("file.txt");
// This line isn't needed, but is really useful 
// if you're a beginner and don't know where your file is going to end up.
System.out.println(destination.getAbsolutePath());
try {
    Files.write(text, destination, Charset.forName("UTF-8"));
} catch (IOException e) {
    // Useful error handling here
}

Answer 10

使用Apache Commons IO api.这很简单

使用API​​作为

 FileUtils.writeStringToFile(new File("FileNameToWrite.txt"), "stringToWrite");

Maven依赖

<dependency>
    <groupId>commons-io</groupId>
    <artifactId>commons-io</artifactId>
    <version>2.4</version>
</dependency>

Answer 11

如果您需要基于单个字符串创建文本文件:

import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Paths;

public class StringWriteSample {
    public static void main(String[] args) {
        String text = "This is text to be saved in file";

        try {
            Files.write(Paths.get("my-file.txt"), text.getBytes());
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

Answer 12

使用它,它非常易读:

import java.nio.file.Files;
import java.nio.file.Paths;

Files.write(Paths.get(path), lines.getBytes(), StandardOpenOption.WRITE);

Answer 13

你可以这样做:

import java.io.*;
import java.util.*;

class WriteText
{
    public static void main(String[] args)
    {   
        try {
            String text = "Your sample content to save in a text file.";
            BufferedWriter out = new BufferedWriter(new FileWriter("sample.txt"));
            out.write(text);
            out.close();
        }
        catch (IOException e)
        {
            System.out.println("Exception ");       
        }

        return ;
    }
};

Answer 14

import java.io.*;

private void stringToFile( String text, String fileName )
 {
 try
 {
    File file = new File( fileName );

    // if file doesnt exists, then create it 
    if ( ! file.exists( ) )
    {
        file.createNewFile( );
    }

    FileWriter fw = new FileWriter( file.getAbsoluteFile( ) );
    BufferedWriter bw = new BufferedWriter( fw );
    bw.write( text );
    bw.close( );
    //System.out.println("Done writing to " + fileName); //For testing 
 }
 catch( IOException e )
 {
 System.out.println("Error: " + e);
 e.printStackTrace( );
 }
} //End method stringToFile

您可以将此方法插入到类中.如果在具有main方法的类中使用此方法,请通过添加静态关键字将此类更改为static.无论哪种方式,您都需要导入java.io.*才能使其工作,否则将无法识别File,FileWriter和BufferedWriter.

Answer 15

使用Java 7:

public static void writeToFile(String text, String targetFilePath) throws IOException
{
    Path targetPath = Paths.get(targetFilePath);
    byte[] bytes = text.getBytes(StandardCharsets.UTF_8);
    Files.write(targetPath, bytes, StandardOpenOption.CREATE);
}

Answer 16

使用org.apache.commons.io.FileUtils:

FileUtils.writeStringToFile(new File("log.txt"), "my string", Charset.defaultCharset());

Answer 17

如果您只关心将一个文本块推送到文件,则每次都会覆盖它.

JFileChooser chooser = new JFileChooser();
int returnVal = chooser.showSaveDialog(this);
if (returnVal == JFileChooser.APPROVE_OPTION) {
    FileOutputStream stream = null;
    PrintStream out = null;
    try {
        File file = chooser.getSelectedFile();
        stream = new FileOutputStream(file); 
        String text = "Your String goes here";
        out = new PrintStream(stream);
        out.print(text);                  //This will overwrite existing contents

    } catch (Exception ex) {
        //do something
    } finally {
        try {
            if(stream!=null) stream.close();
            if(out!=null) out.close();
        } catch (Exception ex) {
            //do something
        }
    }
}

此示例允许用户使用文件选择器选择文件.

Answer 18

private static void generateFile(String stringToWrite, String outputFile) {
    try {       
        FileWriter writer = new FileWriter(outputFile);
        writer.append(stringToWrite);
        writer.flush();
        writer.close();
        log.debug("New File is generated ==>"+outputFile);
    } catch (Exception exp) {
        log.error("Exception in generateFile ", exp);
    }
}

Answer 19

基本上与这里的答案相同，但很容易复制/粘贴，而且它就可以工作;-)

  import java.io.FileWriter;

  public void saveToFile(String data, String filename) {
    try (
      FileWriter fw = new FileWriter(filename)) {
      fw.write(data);
    } catch (Exception e) {
      throw new RuntimeException(e);
    }
  }