Java线程同步问题synchronized

Android USB 读写以前都是一读一写，但有些机器会出问题。就采用读写异步的方法。

关键不在USB，在线程异步，记录下。

使用对象锁，Object自带的，然后使用Object的方法wait和notify/notifyAll

使用方法简单，记录下

public synchronized int LRA_setRegister(int index,int address, int value) {
int ret = 0xffff;
byte[] cmd = {0x55,0x02,0x00,0x53,0x03,0x03,0x00,0x00};
mCMDNow = 0x53;
cmd[5] = (byte)index;
cmd[6] = (byte)(address);
cmd[7] = (byte)(value);
byte[] cmd4send = CRC16.data4Send(cmd);
writeUsbSerial(cmd4send,cmd4send.length);
synchronized (syncObject){
try {
syncObject.wait(1000);
} catch (InterruptedException e) {
e.printStackTrace();
}
ret = mRegisterSetValue;
}
return ret;
}

/**
* Read register value by address
* @param address of registers need to read
* @return data in register
*/
public synchronized int LRA_getRegister(int index,int address) {
int ret = 0xffff;
byte[] cmd = {0x55,0x02,0x00,0x54,0x02,0x03,0x00};
mCMDNow = 0x54;
cmd[5] = (byte)index;
cmd[6] = (byte)(address);
byte[] cmd4send = CRC16.data4Send(cmd);
writeUsbSerial(cmd4send,cmd4send.length);
synchronized (syncObject){
try {
syncObject.wait(1000);
} catch (InterruptedException e) {
e.printStackTrace();
}
ret = mRegisterReadValue;
}
return ret;
}

public byte[] LRA_getDeviceID() {
byte[] cmd = {0x55,0x02,0x00,(byte) 0xFF,0x01,0x00,0x44,0x7e};
mCMDNow = (byte) 0xff;
writeUsbSerial(cmd,cmd.length);
synchronized (syncObject){
try {
syncObject.wait(1000);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
return mDeviceID;
}

private boolean mUSBReadSwitch = false;
private int mUsbReadDataLen = 20;
private byte[] mUsbReadData = new byte[mUsbReadDataLen];
private byte[] mUsbReadDataCLean = new byte[mUsbReadDataLen];
private byte mCMDNow = 0x00;
private Object syncObject = new Object();
//values return
private byte[] mDeviceID = new byte[13];
private byte mRegisterReadValue = 0x00;
private byte mRegisterSetValue = 0x00;
class UsbReadThread extends Thread{
@Override
public void run() {
super.run();
while (mUSBReadSwitch){
int ret = readUsbSerial(mUsbReadData,mUsbReadDataLen);
// Log.e("ivan","ret = " + ret);
if(ret != -1) {
readReturnDataFromUSB(mCMDNow, mUsbReadData);
System.arraycopy(mUsbReadDataCLean, 0, mUsbReadData, 0, mUsbReadDataLen);
}
}
}
}

public byte[] getmDeviceID(){
return mDeviceID;
}

private int readReturnDataFromUSB(byte cmd, byte[] dataRead){
int ret = 0xffff;
showDataDetail(dataRead,"readReturnDataFromUSB");
if(dataRead[0] == (byte)0xAA){
if(cmd == dataRead[3]){

4000
switch (dataRead[3]){
case 0x53:
mRegisterSetValue = dataRead[5];
// mListener.onEventCome(Event.EVENT_REGISTER_WRITE_RESULT_OK,ret);
synchronized (syncObject) {
syncObject.notify();
}
break;
case 0x54:
mRegisterReadValue = dataRead[5];
// mListener.onEventCome(Event.EVENT_REGISTER_READ_RESULT_OK,mRegisterReadValue);
synchronized (syncObject) {
syncObject.notify();
}
break;
case (byte) 0xff:
System.arraycopy(dataRead,4,mDeviceID,0,13);
showDataDetail(mDeviceID,"readReturnDataFromUSB");
// mListener.onEventCome(Event.EVENT_DEVICEID_READ_RESULT,ret);
synchronized (syncObject) {
syncObject.notify();
}
break;
default:
break;
}
}else{
// Log.e("ivan","readReturnDataFromUSB Again");
// readReturnDataFromUSB(cmd);
}
}else if((dataRead[0] == 0x00) && (dataRead[1] == 0x00) && (dataRead[2] == 0x00) && (dataRead[3] == 0x00) && (dataRead[4] == 0x00)
&& (dataRead[5] == 0x00)){
if(mListener != null) {
mListener.onUsbState(Event.OPEN_UART_STATE_PULLOUT);
}
}
return ret;
}