Java对网络图片/本地图片转换成Base64编码和解码

一、将本地图片转换成Base64编码字符串

/**
     * 将本地图片转换成Base64编码字符串
     *
     * @param imgFile 图片目录路径
     * @return
     */
    public static String getImgFileToBase64(String imgFile) {
        //将图片文件转化为字节数组字符串，并对其进行Base64编码处理
        InputStream inputStream = null;
        byte[] buffer = null;
        //读取图片字节数组
        try {
            inputStream = new FileInputStream(imgFile);
            int count = 0;
            while (count == 0) {
                count = inputStream.available();
            }
            buffer = new byte[count];
            inputStream.read(buffer);
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            if (inputStream != null) {
                try {
                    // 关闭inputStream流
                    inputStream.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
        // 对字节数组Base64编码
        return new BASE64Encoder().encode(buffer);
    }

二、将网络图片转换成Base64编码字符串

/**
     * 将网络图片转换成Base64编码字符串
     *
     * @param imgUrl 网络图片Url
     * @return
     */
    public static String getImgUrlToBase64(String imgUrl) {
        InputStream inputStream = null;
        ByteArrayOutputStream outputStream = null;
        byte[] buffer = null;
        try {
            // 创建URL
            URL url = new URL(imgUrl);
            // 创建链接
            HttpURLConnection conn = (HttpURLConnection) url.openConnection();
            conn.setRequestMethod("GET");
            conn.setConnectTimeout(5000);
            inputStream = conn.getInputStream();
            outputStream = new ByteArrayOutputStream();
            // 将内容读取内存中
            buffer = new byte[1024];
            int len = -1;
            while ((len = inputStream.read(buffer)) != -1) {
                outputStream.write(buffer, 0, len);
            }
            buffer = outputStream.toByteArray();
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            if (inputStream != null) {
                try {
                    // 关闭inputStream流
                    inputStream.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            if (outputStream != null) {
                try {
                    // 关闭outputStream流
                    outputStream.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
        // 对字节数组Base64编码
        return new BASE64Encoder().encode(buffer);
    }

三、将网络链接图片或者本地图片文件转换成Base64编码字符串（就是对上面的两种进行整合）

/**
     * 将网络链接图片或者本地图片文件转换成Base64编码字符串
     *
     * @param imgStr 网络图片Url/本地图片目录路径
     * @return
     */
    public static String getImgStrToBase64(String imgStr) {
        InputStream inputStream = null;
        ByteArrayOutputStream outputStream = null;
        byte[] buffer = null;
        try {
            //判断网络链接图片文件/本地目录图片文件
            if (imgStr.startsWith("http://") || imgStr.startsWith("https://")) {
                // 创建URL
                URL url = new URL(imgStr);
                // 创建链接
                HttpURLConnection conn = (HttpURLConnection) url.openConnection();
                conn.setRequestMethod("GET");
                conn.setConnectTimeout(5000);
                inputStream = conn.getInputStream();
                outputStream = new ByteArrayOutputStream();
                // 将内容读取内存中
                buffer = new byte[1024];
                int len = -1;
                while ((len = inputStream.read(buffer)) != -1) {
                    outputStream.write(buffer, 0, len);
                }
                buffer = outputStream.toByteArray();
            } else {
                inputStream = new FileInputStream(imgStr);
                int count = 0;
                while (count == 0) {
                    count = inputStream.available();
                }
                buffer = new byte[count];
                inputStream.read(buffer);
            }
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            if (inputStream != null) {
                try {
                    // 关闭inputStream流
                    inputStream.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            if (outputStream != null) {
                try {
                    // 关闭outputStream流
                    outputStream.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
        // 对字节数组Base64编码
        return new BASE64Encoder().encode(buffer);
    }

四、将图片Base64编码转换成img图片文件（解码）

/**
     * 将图片Base64编码转换成img图片文件
     *
     * @param imgBase64 图片Base64编码
     * @param imgPath   图片生成路径
     * @return
     */
    public static boolean getImgBase64ToImgFile(String imgBase64, String imgPath) {
        boolean flag = true;
        OutputStream outputStream = null;
        try {
            // 解密处理数据
            byte[] bytes = new BASE64Decoder().decodeBuffer(imgBase64);
            for (int i = 0; i < bytes.length; ++i) {
                if (bytes[i] < 0) {
                    bytes[i] += 256;
                }
            }
            outputStream = new FileOutputStream(imgPath);
            outputStream.write(bytes);
        } catch (Exception e) {
            e.printStackTrace();
            flag = false;
        } finally {
            if (outputStream != null) {
                try {
                    // 关闭outputStream流
                    outputStream.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
        return flag;
    }