如何在Java中将InputStream转换为File

分手后的思念是犯贱 2023-02-15 07:38 103阅读 0赞

以下是一些将`InputStream`转换为`File` Java示例

1.  手动将`InputStream`复制到`FileOutputStream`
2.  Apache Commons IO – `FileUtils.copyInputStreamToFile`
3.  Java 1.7 NIO `Files.copy`

## 1. FileOutputStream ##

1.1我们必须将数据从`InputStream`手动复制到`OutputStream` 。

InputStreamToFile.java

package com.mkyong;
    
    import java.io.File;
    import java.io.FileOutputStream;
    import java.io.IOException;
    import java.io.InputStream;
    import java.net.URI;
    
    public class InputStreamToFile {
    
        private static final String FILE_TO = "d:\\download\\google.txt";
    
        public static void main(String[] args) throws IOException {
    
            URI u = URI.create("https://www.google.com/");
            try (InputStream inputStream = u.toURL().openStream()) {
                File file = new File(FILE_TO);
                copyInputStreamToFile(inputStream, file);
            }
        }
    
        // InputStream -> File
        private static void copyInputStreamToFile(InputStream inputStream, File file) 
    		throws IOException {
    
            try (FileOutputStream outputStream = new FileOutputStream(file)) {
    
                int read;
                byte[] bytes = new byte[1024];
    
                while ((read = inputStream.read(bytes)) != -1) {
                    outputStream.write(bytes, 0, read);
                }
    
    			// commons-io
                //IOUtils.copy(inputStream, outputStream);
    
            }
    
        }
    
    }

## 2. Apache Commons IO ##

2.1 `FileUtils.copyInputStreamToFile`在Apache Commons IO中可用

pom.xml

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

InputStreamToFile2.java

package com.mkyong;
    
    import org.apache.commons.io.FileUtils;
    
    import java.io.File;
    import java.io.IOException;
    import java.io.InputStream;
    import java.net.URI;
    
    public class InputStreamToFile2 {
    
        private static final String FILE_TO = "d:\\download\\google.txt";
    
        public static void main(String[] args) throws IOException {
    
            URI u = URI.create("https://www.google.com/");
            try (InputStream inputStream = u.toURL().openStream()) {
    
                File file = new File(FILE_TO);
    
    			// commons-io
                FileUtils.copyInputStreamToFile(inputStream, file);
            }
    
        }
    
    }

## 3. Java 1.7 NIO ##

3.1如果只想将`inputStream`保存到某个文件中，请尝试使用Java 1.7 NIO `Files.copy`

InputStreamToFile3.java

package com.mkyong;
    
    import java.io.IOException;
    import java.io.InputStream;
    import java.net.URI;
    import java.nio.file.Files;
    import java.nio.file.Paths;
    
    public class InputStreamToFile3 {
    
        private static final String FILE_TO = "d:\\download\\google.txt";
    
        public static void main(String[] args) throws IOException {
    
            URI u = URI.create("https://www.google.com/");
            try (InputStream inputStream = u.toURL().openStream()) {
    
    			//Java 1.7
                Files.copy(inputStream, Paths.get(FILE_TO));
    
            }
    
        }
    
    }

## 4.旧时光 ##

4.1在过去的Java 1.7之前，我们必须手动关闭所有资源。

InputStreamToFile4.java

package com.mkyong;
    
    import java.io.*;
    
    public class InputStreamToFile4 {
    
        public static void main(String[] args) {
    
            InputStream inputStream = null;
            OutputStream outputStream = null;
    
            try {
                // read this file into InputStream
                inputStream = new FileInputStream("/Users/mkyong/holder.js");
    
                // write the inputStream to a FileOutputStream
                outputStream = new FileOutputStream(new File("/Users/mkyong/holder-new.js"));
    
                int read = 0;
                byte[] bytes = new byte[1024];
    
                while ((read = inputStream.read(bytes)) != -1) {
                    outputStream.write(bytes, 0, read);
                }
    
                System.out.println("Done!");
    
            } catch (IOException e) {
                e.printStackTrace();
            } finally {
                if (inputStream != null) {
                    try {
                        inputStream.close();
                    } catch (IOException e) {
                        e.printStackTrace();
                    }
                }
                if (outputStream != null) {
                    try {
                        outputStream.close();
                    } catch (IOException e) {
                        e.printStackTrace();
                    }
    
                }
            }
        }
    
    }

## 5.将文件转换为InputStream ##

这很容易：

File file = new File("d:\\download\\google.txt");
        InputStream inputStream = new FileInputStream(file);

> **注意**  
> 您可能对此String的InputStream感兴趣

## 参考文献 ##

*  [文件JavaDocs][JavaDocs]
 *  如何在Java中将InputStream转换为String
 *  [Apache Commons IO][]

标签：输入 [流][Link 1] [io][] [java][] [java 7][] [java.io][] [nio][]

> 翻译自: [https://mkyong.com/java/how-to-convert-inputstream-to-file-in-java/][https_mkyong.com_java_how-to-convert-inputstream-to-file-in-java]

[JavaDocs]: https://docs.oracle.com/javase/7/docs/api/java/nio/file/Files.html
[Apache Commons IO]: https://commons.apache.org/proper/commons-io/
[Link 1]: https://mkyong.com/tag/inputstream/
[io]: https://mkyong.com/tag/io/
[java]: https://mkyong.com/tag/java/
[java 7]: https://mkyong.com/tag/java-7/
[java.io]: https://mkyong.com/tag/java-io/
[nio]: https://mkyong.com/tag/nio/
[https_mkyong.com_java_how-to-convert-inputstream-to-file-in-java]: https://mkyong.com/java/how-to-convert-inputstream-to-file-in-java/