一段java并发编程代码

1 snmpGetDevicesTask方法

public static Map<String,CapEbu> snmpGetDevicesTask(List<String> ipList, List<String> oidList) {
if(ipList==null||ipList.size()==0 || oidList==null || oidList.size()==0) return null;
Map<String,CapEbu> ebuMap = new HashMap<String,CapEbu>();
List<CapEbu> ebulist = new Vector<CapEbu>();
int ipsSize = ipList.size();//ip段大小
//指定循环次数，如果不指定循环次数且IP段大小是65536，那么线程池的一个任务就包含600多个ip，那么在极短时间内，当前任务会有一个监听器线程，该线程可能会响应不过来，因为要处理600多个响应。
//现在指定一次循环，线程池就只处理1000个ip,同时该循环中只向线程池发布100个任务，平均一个任务只处理10个ip。
int cicleNumber = (ipsSize%ScanDeviceContants.DEAL_IPNUMBER == 0)?(ipsSize/ScanDeviceContants.DEAL_IPNUMBER):(ipsSize/ScanDeviceContants.DEAL_IPNUMBER+1);

//创建线程执行器
ThreadPoolExecutor executor = (ThreadPoolExecutor)Executors.newFixedThreadPool(ScanDeviceContants.THREADPOOL_SIZE);
List<Future<List<CapEbu>>> resultList = new ArrayList<Future<List<CapEbu>>>();
for(int cicle=0; cicle<cicleNumber; cicle++){
List<String> iptemp = new ArrayList<String>();
iptemp.addAll(ipList.subList(cicle*ScanDeviceContants.DEAL_IPNUMBER, cicle==cicleNumber-1?ipList.size():(cicle+1)*ScanDeviceContants.DEAL_IPNUMBER));

//创建ip分配器
AssignIps assignIps = new AssignIps(iptemp);

for(int i=0; i<assignIps.getTaskSize(); i++){
SnmpEbuTask snmpEbuTask = new SnmpEbuTask(assignIps.getAssignedIps(i),oidList);
Future<List<CapEbu>> result = executor.submit(snmpEbuTask);
resultList.add(result);
snmpEbuTask = null;
}
System.out.println("CorePoolSize:"+executor.getCorePoolSize()+"---"+"MaximumPoolSize:"+executor.getMaximumPoolSize()+"-----LargestPoolSize:"+executor.getLargestPoolSize()+"-------PoolSize:"+executor.getPoolSize());
executor.allowCoreThreadTimeOut(false);
System.out.println("executor.getKeepAliveTime(TimeUnit.MILLISECONDS):"+executor.getKeepAliveTime(TimeUnit.NANOSECONDS));

//直到所有任务都已完成，则停止循环
do {
try {
TimeUnit.MILLISECONDS.sleep(500);
System.out.println("线程活跃数量："+executor.getActiveCount());
} catch (InterruptedException e) {
e.printStackTrace();
}
}
// while (executor.getCompletedTaskCount()<resultList.size()*(cicle+1));
while (executor.getActiveCount()!=0);

System.out.println("线程活跃数量："+executor.getActiveCount()+"，执行器执行完的数量："+executor.getCompletedTaskCount());
System.out.println("执行器"+(cicle+1)+"是否已终止："+executor.isTerminated());
}
executor.shutdown();//关闭线程执行器
//所有任务已经完成，开始取出任务
for (int i=0; i<resultList.size(); i++) {
Future<List<CapEbu>> result=resultList.get(i);
if(result.isDone()){
try {
List<CapEbu> ebus = result.get();
if(ebus!=null&&ebus.size()>0){
for(int j = 0 ; j < ebus.size() ; j++){
if(!ebuMap.containsKey(ebus.get(j).getEbuIp())){
ebuMap.put(ebus.get(j).getEbuIp(), ebus.get(j));
System.out.println("放入map中,测试结果为 : ip = " + ebus.get(j).getEbuIp());
}

}
}
// ebulist.removeAll(ebus);
// ebulist.addAll(ebus);
} catch (InterruptedException e) {
e.printStackTrace();
} catch (ExecutionException e) {
e.printStackTrace();
}
}
}
return ebuMap;
}

2 SnmpEbuTask.java

import java.util.ArrayList;
import java.util.List;
import java.util.Vector;
import java.util.concurrent.Callable;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.TimeUnit;

import org.snmp4j.CommunityTarget;
import org.snmp4j.PDU;
import org.snmp4j.Snmp;
import org.snmp4j.event.ResponseEvent;
import org.snmp4j.event.ResponseListener;
import org.snmp4j.mp.SnmpConstants;
import org.snmp4j.smi.Address;
import org.snmp4j.smi.GenericAddress;
import org.snmp4j.smi.OID;
import org.snmp4j.smi.OctetString;
import org.snmp4j.smi.VariableBinding;
import org.snmp4j.transport.DefaultUdpTransportMapping;

import com.nufront.euht.model.CapEbu;
import com.nufront.euht.scanDevice.util.OidTranslatorUtil;
import com.nufront.euht.util.Beans;
import com.nufront.euht.util.StringUtil;

public class SnmpEbuTask implements Callable<List<CapEbu>> {
private int version = SnmpConstants.version2c;
private String protocol = "udp";
private int port = 161;

private String community = "euhtpub";
private List<String> ipsAddress;
private List<String> oids;

private List<CapEbu> capEbus = new Vector<CapEbu>();
private Object lock = new Object();//同步锁
private int responseCounter = 0;//响应计数器
private ConcurrentHashMap<String,Object> distinctIp = new ConcurrentHashMap<String,Object>();//ip响应去重器

public SnmpEbuTask(List<String> ipsAddress, List<String> oids) {
this.ipsAddress = ipsAddress;
this.oids = oids;
}

private CommunityTarget createCommunityTarget(String address,String community, int version, long timeOut, int retry) {
Address targetAddress = GenericAddress.parse(address);
CommunityTarget target = new CommunityTarget();
target.setCommunity(new OctetString(community));
target.setAddress(targetAddress);
target.setVersion(version);
target.setTimeout(timeOut); // milliseconds
target.setRetries(retry);
return target;
}

@Override
public List<CapEbu> call() throws Exception {
String address = null;
CommunityTarget target = null;
DefaultUdpTransportMapping transport = null;
Snmp snmp = null;

try {

transport = new DefaultUdpTransportMapping();
transport.listen();
snmp = new Snmp(transport);
PDU pdu = new PDU();
pdu.setType(PDU.GET);

for (String oid : oids) {
pdu.add(new VariableBinding(new OID(oid)));
}

ResponseListener listener = new ResponseListener() {
public void onResponse(ResponseEvent event) {
((Snmp) event.getSource()).cancel(event.getRequest(), this);
PDU response = event.getResponse();
PDU request = event.getRequest();
System.out.println("[request]:" + request);
String ip = null;
if (Beans.isNotEmpty(event.getPeerAddress())) {
ip = event.getPeerAddress().toString(); // 获取IP
if(!StringUtil.isNullOrBlank(ip)){
ip = ip.split("/")[0];
System.out.println("registerListener, ip=" + ip);
}
}
if (response == null) {
System.out.println("[ERROR]: response is null, ip is "+ip);
} else if (response.getErrorStatus() != 0) {
System.out.println("[ERROR]: response status"
+ response.getErrorStatus() + " Text:"
+ response.getErrorStatusText()
+ " ip is "+ip);
} else {
if(ip.equals("192.168.22.226")){
System.out.println();
}
System.out.println("Received response Success!!!"+" ip:"+ip);
CapEbu capEbu = new CapEbu();
capEbu.setEbuIp(ip);
List<OidData> oidDatas = new ArrayList<OidData>();
for (int i = 0; i < response.size(); i++) {
VariableBinding vb = response.get(i);
OidData oidData = new OidData();
oidData.setOid(vb.getOid().toString());
oidData.setValue(vb.getVariable().toString());
oidDatas.add(oidData);
}
if(Beans.isNotEmpty(oidDatas) && oidDatas.size()>0){
for(OidData oidData : oidDatas){
OidTranslatorUtil.oidvalueConvertToName(oidData, capEbu);
}
}
if(!distinctIp.containsKey(ip)){
distinctIp.put(ip, new Object());
capEbus.add(capEbu);
System.out.println("capEbus.size():"+capEbus.size());
}
}
synchronized (lock) {
responseCounter++;
System.out.println("responseCounter++:"+responseCounter);
}
}
};
for(int i=0; i<ipsAddress.size(); i++){
address = protocol + ":" + ipsAddress.get(i) + "/" + port;
target = createCommunityTarget(address, community, version, 1000L, 5);
snmp.send(pdu, target, null, listener);
System.out.println("asynchronous send pdu wait for response...");
}
long baselineTime = System.currentTimeMillis();
while(responseCounter < ipsAddress.size()){
long sendedTime = System.currentTimeMillis();
//如果逗留时间超过5秒，有可能是网络原因或者其他原因，导致响应不会到达监听器，为避免死循环，则应马上结束循环。
if(sendedTime-baselineTime>5000){
break;
}
TimeUnit.MILLISECONDS.sleep(1000);
}

return capEbus;
} catch (Exception e) {
System.out.println("SNMP GetNext Exception:" + e);
}finally{
snmp.close();//扫描结束后，得立刻关掉snmp，否则监听器的线程将一直处于wait状态，任务数过多的话，线程创建也将越来越多，最终导致系统崩溃
transport.close();
}
return null;
}

}