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import org.apache.commons.codec.binary.*;

import java.io.*;
import java.net.*;

/**
 * 将file文件转换为Base64<br>
 * 将base64编码字符串解码成file
 *
 * @author <a href = "mailto:zhuyongsheng@njpkhuan.cn" > 朱永胜 </a >
 */
public class File2Base64Util {
    /**
     * 对字节数组字符串进行Base64解码并生成图片
     *
     * @param fileStr      图片数据
     * @param fileFilePath 保存图片全路径地址
     */
    public static Boolean generateBase64StringToFile(String fileStr, String fileFilePath) {
        if (fileStr == null) {
            return false;
        }
        try {
            byte[] b = Base64.decodeBase64(fileStr);
            for (int i = 0; i < b.length; ++i) {
                if (b[i] < 0) {
                    b[i] += 256;
                }
            }
            OutputStream out = new FileOutputStream(fileFilePath);
            out.write(b);
            out.flush();
            out.close();
            return true;
        } catch (Exception e) {
            e.printStackTrace();
            return false;
        }
    }

    /**
     * 将文件转换成Base64编码
     * 将文件转化为字节数组字符串，并对其进行Base64编码处理
     *
     * @param localFilePath 待处理图片
     */
    public static String getFileBase64StrByLocalFile(String localFilePath) {
        InputStream in = null;
        byte[] data = null;
        //读取图片字节数组
        try {
            in = new FileInputStream(localFilePath);
            data = new byte[in.available()];
            in.read(data);
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            try {
                if (in != null) {
                    in.close();
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        if (data == null || data.length == 0) {
            return "";
        }
        return new String(Base64.encodeBase64(data));
    }

    /**
     * 将文件转换成Base64编码
     * 将文件转化为字节数组字符串，并对其进行Base64编码处理
     *
     * @param fileUrl 待处理文件网络地址
     */
    public static String getFileBase64StrByUrl(String fileUrl) {
        BufferedInputStream in = null;
        ByteArrayOutputStream out = null;
        try {
            URL ur = new URL(fileUrl);
            in = new BufferedInputStream(ur.openStream());
            out = new ByteArrayOutputStream(1024);
            byte[] temp = new byte[1024];
            int size = 0;
            while ((size = in.read(temp)) != -1) {
                out.write(temp, 0, size);
            }
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            try {
                if (in != null) {
                    in.close();
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        if (out == null) {
            return "";
        }
        byte[] content = out.toByteArray();
        return new String(Base64.encodeBase64(content));
    }

    public static void main(String[] args) {
        //待读取图片地址
        String imgFile = "d:\\source.png";
        //待处理的图片
        String sourceImage = getFileBase64StrByLocalFile(imgFile);
        String destImagePath = "d:\\target.png";
        //新生成的图片
        if (generateBase64StringToFile(sourceImage, destImagePath)) {
            System.out.println("生成成功！");
        } else {
            System.out.println("生成失败！");
        }
    }
}