Java –如何将字符串保存到文件-蒲公英云

Java –如何将字符串保存到文件

在Java中，有很多方法可以将String写入文件。

1. Java 11 – Files.writeString

最后，在java.nio添加了一个新方法，可以轻松地将字符串保存到File 。

StringToFileJava11.java

package com.mkyong;
import java.io.IOException;
import java.nio.charset.StandardCharsets;
import java.nio.file.Files;
import java.nio.file.Paths;
import java.nio.file.StandardOpenOption;
public class StringToFileJava11 {
    public static void main(String[] args) {
        String content = "Hello World \r\nJava!\r\n";
        String path = "c:\\projects\\app.log";
        try {
            // Java 11 , default StandardCharsets.UTF_8
            Files.writeString(Paths.get(path), content);
            // encoding
            // Files.writeString(Paths.get(path), content, StandardCharsets.US_ASCII);
            // extra options
            // Files.writeString(Paths.get(path), content, 
            //        StandardOpenOption.CREATE, StandardOpenOption.APPEND);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

c:\\projects\\app.log

Hello World 
Java!

2. Java 7 – Files.write

StringToFileJava7.java

package com.mkyong;
import java.io.IOException;
import java.nio.charset.StandardCharsets;
import java.nio.file.Files;
import java.nio.file.Paths;
import java.nio.file.StandardOpenOption;
public class StringToFileJava7 {
    public static void main(String[] args) {
        String content = "Hello World \r\nJava!\r\n";
        String path = "c:\\projects\\app.log";
        try {
            // Java 7
            Files.write(Paths.get(path), content.getBytes());
            // encoding
            // Files.write(Paths.get(path), content.getBytes(StandardCharsets.UTF_8));
            // extra options
            // Files.write(Paths.get(path), content.getBytes(), 
            //        StandardOpenOption.CREATE, StandardOpenOption.APPEND);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

输出量

c:\\projects\\app.log

Hello World 
Java!

3. Apache Commons IO

pom.xml

<dependency>
        <groupId>commons-io</groupId>
        <artifactId>commons-io</artifactId>
        <version>2.6</version>
    </dependency>

CommonsIOExample.java

package com.mkyong;
import org.apache.commons.io.FileUtils;
import java.io.File;
import java.io.IOException;
import java.nio.charset.StandardCharsets;
public class CommonsIOExample {
    public static void main(String[] args) {
        String content = "Hello World \r\nJava!\r\n";
        String path = "c:\\projects\\app2.log";
        try {
            FileUtils.writeStringToFile(new File(path), content, StandardCharsets.UTF_8);
            // append
            // FileUtils.writeStringToFile(new File(path), content, StandardCharsets.UTF_8, true);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

4. BufferedWriter

4.1在过去：

BufferedWriterExample.java

package com.mkyong;
import java.io.BufferedWriter;
import java.io.FileWriter;
import java.io.IOException;
public class BufferedWriterExample {
    public static void main(String[] args) {
        String content = "Hello World \r\nJava!\r\n";
        String path = "c:\\projects\\app.log";
        try (FileWriter writer = new FileWriter(path);
              BufferedWriter bw = new BufferedWriter(writer)) {
            bw.write(content);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

4.2或者像这样，手动关闭所有资源resources

BufferedWriterExampleBeforeJava7.java

package com.mkyong;
import java.io.BufferedWriter;
import java.io.FileWriter;
import java.io.IOException;
public class BufferedWriterExampleBeforeJava7 {
    public static void main(String[] args) {
        String content = "Hello World \r\nJava!\r\n";
        String path = "c:\\projects\\app.log";
        BufferedWriter bw = null;
        FileWriter fw = null;
        try {
            fw = new FileWriter(path);
            bw = new BufferedWriter(fw);
            bw.write(content);
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            try {
                if (bw != null)
                    bw.close();
                if (fw != null)
                    fw.close();
            } catch (IOException ex) {
                ex.printStackTrace();
            }
        }
    }
}