android 读取文件为byte数组

经常要使用字节数组

package com.android.dex.util;

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;

public final class FileUtils {
    private FileUtils() {
    }

    public static boolean hasArchiveSuffix(String str) {
        return str.endsWith(".zip") || str.endsWith(".jar") || str.endsWith(".apk");
    }

    public static byte[] readFile(File file) {
        if (!file.exists()) {
            throw new RuntimeException(file + ": file not found");
        } else if (!file.isFile()) {
            throw new RuntimeException(file + ": not a file");
        } else if (file.canRead()) {
            long length = file.length();
            int i = (int) length;
            if (i == length) {
                byte[] bArr = new byte[i];
                try {
                    FileInputStream fileInputStream = new FileInputStream(file);
                    int i2 = 0;
                    while (i > 0) {
                        int read = fileInputStream.read(bArr, i2, i);
                        if (read != -1) {
                            i2 += read;
                            i -= read;
                        } else {
                            throw new RuntimeException(file + ": unexpected EOF");
                        }
                    }
                    fileInputStream.close();
                    return bArr;
                } catch (IOException e) {
                    throw new RuntimeException(file + ": trouble reading", e);
                }
            } else {
                throw new RuntimeException(file + ": file too long");
            }
        } else {
            throw new RuntimeException(file + ": file not readable");
        }
    }

    public static byte[] readFile(String str) {
        return readFile(new File(str));
    }
}

使用示例

import com.android.dex.util.FileUtils;
……
File file = new File(Environment.getExternalStorageDirectory()+"/wallpaper.png");
// file 对象
byte[] readFile = FileUtils.readFile(file);
// 或者字符串路径
byte[] readFile = FileUtils.readFile("/storage/emulated/0/wallpaper.png");