使用commons-codec，

下载地址

http://commons.apache.org/proper/commons-codec/

下载commons-codec-1.12-bin.zip，解压出来，引用commons-codec-1.12.jar，import org.apache.commons.codec.binary.Base64;

 

public static byte[] decode(String str) throws Exception {
        Base64 _base64 = new Base64(); 
        return _base64.decodeBase64(str.getBytes());
    }

 public static String encode(byte[] bytes) throws Exception {
        Base64 _base64 = new Base64(); 
        return new String(_base64.encodeBase64Chunked(bytes));
    }

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