let src = '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'
let base64 = new util.Base64Helper();
// base解码
let src_uint8Array = base64.decodeSync(src);
// 解码为utf-8的字符串
let textDecoder = util.TextDecoder.create("utf-8",{ignoreBOM: true})
let src_str = textDecoder.decodeWithStream(src_uint8Array)