如何在Java中将InputStream转换为File

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 。

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

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

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

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。

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
• 如何在Java中将InputStream转换为String
• Apache Commons IO

翻译自: https://mkyong.com/java/how-to-convert-inputstream-to-file-in-java/