spring mvc @autowired不起作用

注意检查点：

1.类上面是否加了@component和@controller注解，要想类中的autowired注解能够正常工作，类的创建必须由spring来掌管，即类必须是一个spring component。

2.注入的变量不能在声明中或者是构造函数中调用。

例如：

package com.arcsoft.lecam.service.impl.lock;

import org.apache.curator.framework.CuratorFramework;
import org.apache.curator.framework.CuratorFrameworkFactory;
import org.apache.curator.framework.recipes.locks.InterProcessLock;
import org.apache.curator.framework.recipes.locks.InterProcessMutex;
import org.apache.curator.retry.RetryNTimes;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;

import com.arcsoft.lecam.constants.Constants;
import com.arcsoft.lecam.constants.Parameter;
import com.arcsoft.lecam.service.common.SysparaService;
import com.arcsoft.lecam.service.lock.DistributedLock;
import com.arcsoft.sumologic.common.LogContainer;
import com.arcsoft.sumologic.common.SumoLogger;
import com.arcsoft.sumologic.common.SumoLoggerThreadLocal;
import com.google.common.base.Strings;

@Component
public class DistributedLockImpl implements DistributedLock{

@Autowired
private SysparaService sysparaService;

private String zkServer;

private static CuratorFramework client;
private static boolean isStarted = false;

SumoLogger sumoLogger;

public String getZkServer() {
return zkServer;
}

public void setZkServer(String zkServer) {
this.zkServer = zkServer;
}

public InterProcessLock getLock(String lockPath) {
sumoLogger = (SumoLogger) SumoLoggerThreadLocal.get();
LogContainer logContainer = sumoLogger.createLogContainer();
if(!isStarted){
//不能在声明中或者是构造函数中调用，否则会出问题
//			zkServer=sysparaService.getPara(Parameter.ZK_LOCK_ADDRESS);
client = CuratorFrameworkFactory.newClient(
zkServer, new RetryNTimes(10, 5000));
client.start();
isStarted = true;
}
logContainer.addPrameter("zookeeper client started ",Constants.ZK_ADDRESS);
String path = lockPath.startsWith("/")? lockPath:"/"+lockPath;
if(Strings.isNullOrEmpty(lockPath))
path = Constants.ZK_LOCK_PATH;

return new InterProcessMutex(client,
path);
}

}

zkServer的值不能写在声明中：

private String zkServer = sysparaService.getPara(Parameter.ZK_LOCK_ADDRESS);

或者写在构造函数中：

public DistributedLockImpl(){

zkServer = sysparaService.getPara(Parameter.ZK_LOCK_ADDRESS);

}