基于Java实现文件和base64字符串转换

    <dependency>
      <groupId>commons-codec</groupId>
      <artifactId>commons-codec</artifactId>
      <version>1.13</version>
    </dependency>

import sun.misc.BASE64Decoder;
import sun.misc.BASE64Encoder;
 
 
import java.io.*;
 
 
public class Base64FileUtil {
 
 
  private static String targetFilePath = "E:\\base2Img\\target\\test.txt";
 
 
  public static void main(String[] args) throws Exception {
    String fileStr = getFileStr("E:\\base2Img\\big test.txt");
    System.out.println("fileStr ===" + fileStr);
    System.out.println(generateFile(fileStr, targetFilePath));
    System.out.println("end");
  }
 
 
  /**
   * 文件转化成base64字符串
   * 将文件转化为字节数组字符串，并对其进行Base64编码处理
   */
  public static String getFileStr(String filePath) {
    InputStream in = null;
    byte[] data = null;
    // 读取文件字节数组
    try {
      in = new FileInputStream(filePath);
      data = new byte[in.available()];
      in.read(data);
      in.close();
    } catch (IOException e) {
      e.printStackTrace();
    } finally {
      try {
        in.close();
      } catch (IOException e) {
        e.printStackTrace();
      }
    }
    // 对字节数组Base64编码
    BASE64Encoder encoder = new BASE64Encoder();
    // 返回 Base64 编码过的字节数组字符串
    return encoder.encode(data);
  }
 
 
  /**
   * base64字符串转化成文件，可以是JPEG、PNG、TXT和AVI等等
   *
   * @param base64FileStr
   * @param filePath
   * @return
   * @throws Exception
   */
  public static boolean generateFile(String base64FileStr, String filePath) throws Exception {
    // 数据为空
    if (base64FileStr == null) {
      System.out.println(" 不行，oops！ ");
      return false;
    }
    BASE64Decoder decoder = new BASE64Decoder();
 
 
    // Base64解码,对字节数组字符串进行Base64解码并生成文件
    byte[] byt = decoder.decodeBuffer(base64FileStr);
    for (int i = 0, len = byt.length; i < len; ++i) {
      // 调整异常数据
      if (byt[i] < 0) {
        byt[i] += 256;
      }
    }
    OutputStream out = null;
    InputStream input = new ByteArrayInputStream(byt);
    try {
      // 生成指定格式的文件
      out = new FileOutputStream(filePath);
      byte[] buff = new byte[1024];
      int len = 0;
      while ((len = input.read(buff)) != -1) {
        out.write(buff, 0, len);
      }
    } catch (IOException e) {
      e.printStackTrace();
    } finally {
      out.flush();
      out.close();
    }
    return true;
  }
 
}