连接wifi打印报错

在引入socket的outputStream报错：TypeError: Cannot read property 'TYPE' of null

    var Socket = plus.android.importClass("java.net.Socket")  
    var InetSocketAddress = plus.android.importClass("java.net.InetSocketAddress")  

    //解决高低版本兼容  
    var StrictMode = plus.android.importClass("android.os.StrictMode")  
    var Build = plus.android.importClass("android.os.Build")  

    if (Build.VERSION.SDK_INT > 9) {  
        var policy = new StrictMode.ThreadPolicy.Builder().permitAll().build()  
        StrictMode.setThreadPolicy(policy)  
    }  

    try {  
        // socket = new Socket(ip, 9100);  
        var socket = new Socket()  
        socket.connect(new InetSocketAddress(ip, 9100), 1500) //设置连接请求超时时间1.5秒  
        socket.setSoTimeout(5000)  

        socket.setKeepAlive(true)  
        var outputStream = socket.getOutputStream()  
        console.log("outputStream: ", outputStream)  
        plus.android.importClass(outputStream)  

        var bytes = plus.android.invoke(str, "getBytes", "gbk")  
        //var bytes = plus.android.invoke(str, 'getBytes', 'UTF-8');  
        outputStream.write(bytes)  
        outputStream.flush()  
        socket.shutdownOutput()  
        return true  
    } catch (e) {  
        console.log(e)  
        uni.showToast({  
            title: "WIFI打印机连接超时，请确定是否有正确设置打印机的IP地址或者确认打印机是否有开机！",  
            icon: 'none'  
        })  
        return false  
        //TODO handle the exception  
    } finally {  
        uni.hideLoading()  
    }