如下的内容段是关于Java Base64加密的内容，应该能对大伙有些用。

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.InputStream;
import java.io.OutputStream;

import javax.mail.internet.MimeUtility;

public class Base64 {
public static byte[] encode(byte[] b) throws Exception {
ByteArrayOutputStream baos = null;
OutputStream b64os = null;
try {
baos = new ByteArrayOutputStream();
b64os = MimeUtility.encode(baos, "base64");
b64os.write(b);
b64os.close();
return baos.toByteArray();
} catch (Exception e) {
throw new Exception(e);
} finally {
try {
if (baos != null) {
baos.close();
baos = null;
}
} catch (Exception e) {
}
try {
if (b64os != null) {
b64os.close();
b64os = null;
}
} catch (Exception e) {
}
}
}

public static byte[] decode(byte[] b) throws Exception {
ByteArrayInputStream bais = null;
InputStream b64is = null;
try {
bais = new ByteArrayInputStream(b);
b64is = MimeUtility.decode(bais, "base64");
byte[] tmp = new byte[b.length];
int n = b64is.read(tmp);
byte[] res = new byte[n];
System.arraycopy(tmp, 0, res, 0, n);

return res;
} catch (Exception e) {
throw new Exception(e);
} finally {
try {
if (bais != null) {
bais.close();
bais = null;
}
} catch (Exception e) {
}
try {
if (b64is != null) {
b64is.close();
b64is = null;
}
} catch (Exception e) {
}
}
}
}