项目中用到的，贴上部份代码

1、扫描配对蓝牙打印机，address为打印机mac地址

function searchDevices(address) {
    let that = this;
    uni.showLoading({
        title: '搜索中...',
        mask: true
    });
    //注册类  
    var main = plus.android.runtimeMainActivity();
    var IntentFilter = plus.android.importClass('android.content.IntentFilter');
    var BluetoothAdapter = plus.android.importClass("android.bluetooth.BluetoothAdapter");
    var BluetoothDevice = plus.android.importClass("android.bluetooth.BluetoothDevice");
    var BAdapter = BluetoothAdapter.getDefaultAdapter();
    var filter = new IntentFilter();
    var bdevice = new BluetoothDevice();
    var on = null;
    var un = null;
    that.ulist = []; //清空容器  
    that.blist = []; //清空容器  
    BAdapter.startDiscovery(); //开启搜索  
    var receiver;
    receiver = plus.android.implements('io.dcloud.android.content.BroadcastReceiver', {
        onReceive: function(context, intent) { //实现onReceiver回调函数  
            plus.android.importClass(intent); //通过intent实例引入intent类，方便以后的‘.’操作  
            if (intent.getAction() == "android.bluetooth.adapter.action.DISCOVERY_FINISHED") {
                main.unregisterReceiver(receiver); //取消监听  
                uni.hideLoading();
            } else {
                var BleDevice = intent.getParcelableExtra(BluetoothDevice.EXTRA_DEVICE);
                //判断是否配对  
                if (BleDevice.getBondState() == bdevice.BOND_NONE) {
                    //参数如果跟取得的mac地址一样就配对  
                    if (address == BleDevice.getAddress()) {
                        if (BleDevice.createBond()) {
                            that.blist.push({
                                id: BleDevice.getAddress(),
                                name: BleDevice.getName()
                            })
                        }
                        main.unregisterReceiver(receiver); //取消监听
                        uni.hideLoading();
                    } else {
                        if (BleDevice.getName() != on) { //判断防止重复添加  
                            that.ulist.push({
                                id: BleDevice.getAddress(),
                                name: BleDevice.getName()
                            })
                        }
                    }
                } else {
                    if (address == BleDevice.getAddress()) {
                        main.unregisterReceiver(receiver); //取消监听
                        uni.hideLoading();
                    }
                    if (BleDevice.getName() != un) { //判断防止重复添加  
                        that.blist.push({
                            id: BleDevice.getAddress(),
                            name: BleDevice.getName()
                        })
                    }
                }
            }

        }
    });
    filter.addAction(bdevice.ACTION_FOUND);
    filter.addAction(BAdapter.ACTION_DISCOVERY_STARTED);
    filter.addAction(BAdapter.ACTION_DISCOVERY_FINISHED);
    filter.addAction(BAdapter.ACTION_STATE_CHANGED);
    main.registerReceiver(receiver, filter); //注册监听 
}

2、打印

var BluetoothAdapter = plus.android.importClass("android.bluetooth.BluetoothAdapter");
var UUID = plus.android.importClass("java.util.UUID");
var uuid = UUID.fromString("00001101-0000-1000-8000-00805F9B34FB");
var BAdapter = BluetoothAdapter.getDefaultAdapter();

function print(list) {
    const mac_address = uni.getStorageSync("macAddress");
    const reg = /[A-Fa-f0-9]{2}:[A-Fa-f0-9]{2}:[A-Fa-f0-9]{2}:[A-Fa-f0-9]{2}:[A-Fa-f0-9]{2}:[A-Fa-f0-9]{2}/;
    let resMsg = {
        success: false,
        message: ""
    };
    let that = this;
    if (!mac_address || !reg.test(mac_address)) {
        resMsg.message = '请选择蓝牙打印机';
        return resMsg;
    }
    uni.showLoading({
        title: '打印中...',
        mask: true
    })
    let device = BAdapter.getRemoteDevice(mac_address);
    plus.android.importClass(device);
    let bluetoothSocket = device.createInsecureRfcommSocketToServiceRecord(uuid);
    plus.android.importClass(bluetoothSocket);
    if (!bluetoothSocket.isConnected()) {
        try {
            bluetoothSocket.connect();
        } catch (e) {
            uni.hideLoading();
            resMsg.message = '打印机连接失败';
            return resMsg;
        }
    }
    if (bluetoothSocket.isConnected()) {
        var outputStream = bluetoothSocket.getOutputStream();
        plus.android.importClass(outputStream);
        list.forEach(t => {
            var bytes = plus.android.invoke(t.data, 'getBytes', 'UTF-8');
            outputStream.write(bytes);
        });
        outputStream.flush();
        device = null //这里关键  
        bluetoothSocket.close(); //必须关闭蓝牙连接否则意外断开的话打印错误  
        uni.hideLoading();
        resMsg.success = true;
        resMsg.message = '数据发送成功';
        return resMsg;
    }

}

3、调用方法打印

    uni.openBluetoothAdapter({
        success(res) {
            let list = [];
            //打印ZPL命令数据，XA开始XZ结束，可多个拼接到一起为一条数据。
            let ss = "^XA^MNW^JUS^CI28";
            ss += "^FO0,45^A@N,36,18,E:MSUNG24.FNT^FD箱码:^FS";
            ss += "^FO90,25^JMA^MD20^BY2,3,320^BCN,60,Y,N,N^FD1234567890^FS";
            ss += "^FO0,100^A@N,36,18^FD类型:直通^FS";
            ss += "^PQ1,0,1,Y";
            ss += "^XZ";
            //拼接多个打印数据
            ss = ss + ss;
            list.push({id: 1,data: ss}); 
            list.push({id: 2,data: ss + ss}); 
            let msg = print(list);
            if (msg.success){
                console.log("成功")
            }
        },
        fail(e){}
    })