Linux上安装Oracle 10g XE

1. 相关软件：
   Redhat Enterprise Linux 5.1
   jdk-1_5_0_14-linux-i586.bin
   oracle-xe-univ-10.2.0.1-1.0.i386.rpm
   
2. 设置JAVA环境变量
   编辑/etc/profile文件，添加：
   JAVA_HOME=/usr/java/default
   CLASSPATH=.:$JAVA_HOME/lib/dt.jar:$JAVA_HOME/lib/tools.jar
   export  JAVA_HOME JAVA_HOME
   保存后退出重新登陆
   
3. 安装oracle
   修改内核参数
   编辑/etc/sysctl.conf文件，添加：
   kernel.shmall = 2097152Erp100社区)`1p+x]&k
   kernel.shmmax = 2147483648
   1{
   l B:eU/t-U)v f0kernel.shmmni = 4096Erp100社区\2U/]#]*Z&P|Ksk ^5s
   kernel.sem = 250 32000 100 128
   bS"^8l ^0fs.file-max = 65536Erp100社区#o(Z,GU4_�K|C"Vw`
   net.ipv4.ip_local_port_range = 1024 65000
   # /sbin/sysctl -p
   
   # echo 65536 > /proc/sys/fs/file-max
   编辑文件/etc/security/limits.conf ，插入 * - nofile 65536  
   重启动
   
   创建oracle用户
   # /usr/sbin/groupadd oinstall
   # /usr/sbin/groupadd dba
   # /usr/sbin/useradd -m -g oinstall -G dba oracle
   
   检查包依赖性：
   makeErp100社区&i+B6IV D*b7Y{
   S7dZ[
   openmotif-devel
   s@ lkk!EG.y0openmotifErp100社区Mu*tL&GN`^&N
   binutils
   K]:{#ZP ]8]u${0setarchErp100社区5_{EMcl9AF,SD
   compat-db
   ` \co1B#X%@Z-S#aD2sl%n0compat-gcc-32-c++
   l[Ri NF bAgk0compat-libstdc++
   2B.Y:q4~A7DM L0compat-gcc
   libaio
   
   安装oracle包：
   # rpm -ivh oracle-xe-univ-10.2.0.1-1.0.i386.rpm
   # /etc/rc.d/init.d/oracle-xe configure
   根据提示设置8080、1521端口，还有sys和system的密码，开机是否启动等。
   
   编辑/etc/profile文件，添加：
   ORACLE_HOME=/usr/lib/oracle/xe/app/oracle/product/10.2.0/server/
   ORACLE_SID=XE
   ORACLE_BASE=/usr/lib/oracle/xe/app/oracle/
   PATH=$PATH:$JAVA_HOME/bin:$ORACLE_HOME/bin
   export  ORACLE_HOME ORACLE_SID ORACLE_BASE
   保存后退出重新登陆
   
   关闭oracle
   # /etc/rc.d/init.d/oracle-xe stop
   启动oracle
   # /etc/rc.d/init.d/oracle-xe start
   
   创建数据库新用户
   # su - oracle
   $ sqlplus system@XE
   sqlplus> create user userName identified by password;
   sqlplus> grant dba to userName;
   sqlplus> grant unlimited tablespace to userName;
   
   

JBoss 5修改EJB3连接池大小

本文所做配置根据JBoss 5.0.0beta3进行
对于EJB3远程调用连接池的配置，JBoss 5的配置文件与JBoss 4相比有些变化，步骤如下：
修改 $JBOSS_HOME/server/all/ejb3-connectors-service.xml, 初始内容如下：

   <mbean code=" org.jboss.remoting.transport.Connector"
          name="jboss.remoting:type=Connector,name=DefaultEjb3Connector,handler=ejb3">
      <attribute name="InvokerLocator">socket://${jboss.bind.address}:3873</attribute>
      <attribute name="Configuration">
         <handlers>
            <handler subsystem="AOP">org.jboss.aspects.remoting.AOPRemotingInvocationHandler</handler>
         </handlers>
      </attribute>
   </mbean>

改为：

   <mbean code="org.jboss.remoting.transport.Connector"
          name=" jboss.remoting:type=Connector,name=DefaultEjb3Connector,handler=ejb3">
      <attribute name="Configuration">
         <config>
            <invoker transport="socket">
               <attribute name="numAcceptThreads">1</attribute>
               <attribute name="maxPoolSize">1000</attribute>
               <attribute name="clientMaxPoolSize" isParam="true">1000</attribute>
               <attribute name="timeout" isParam="true">60000</attribute>
               <attribute name="serverBindAddress">${jboss.bind.address}</attribute>
               <attribute name="serverBindPort">3873</attribute>
               <attribute name="backlog">200</attribute>
            </invoker>
            <handlers>
               <handler subsystem="AOP"> org.jboss.aspects.remoting.AOPRemotingInvocationHandler</handler>
            </handlers>
         </config>
      </attribute>
   </mbean>

其中maxPoolSize，clientMaxPoolSize及 backlog根据需要调整。

JDK5原子变量实践――Ejb调用自动重连

1. ConnectorStatusPair类，需要同步两个状态，一个是进入连接队列线程数，一个是连接时间。目的是同一时间只有一个线程在重连，间隔一定时间只重连一次。
   
   import java.util.concurrent.atomic.AtomicReference;
   
   public class ConnectorStatusPair {
   
       private static class Pair {
   
           final int qLength;
           final long timeStamp;
   
           public Pair(int qLength, long timeStamp) {
               this.qLength = qLength;
               this.timeStamp = timeStamp;
           }
       }
       private AtomicReference<Pair> values;
   
       public ConnectorStatusPair(int qLength, long timeStamp) {
           values = new AtomicReference<Pair>(new Pair(qLength, timeStamp));
       }
      
       public int getQLength() {
           return values.get().qLength;
       }
   
       public long getTimeStamp() {
           return values.get().timeStamp;
       }
   
       /**
        * 原子操作加1
        * @return 更新后的值
        */
       public int incrementAndGetQLength() {
           while (true) {
               Pair oldv = values.get();
               Pair newv = new Pair(oldv.qLength + 1, oldv.timeStamp);
               if (values.compareAndSet(oldv, newv)) {
                   return newv.qLength;
               }
           }
       }
   
       /**
        * 原子操作减一
        * @return 更新后的值
        */
       public int decrementAndGetQLength() {
           while (true) {
               Pair oldv = values.get();
               Pair newv = new Pair(oldv.qLength - 1, oldv.timeStamp);
               if (values.compareAndSet(oldv, newv)) {
                   return newv.qLength;
               }
           }
       }
   
       /**
        * 原子操作比较当前时间减去values保存的时间是否大于给定的时间间隔，以毫秒计，如果为真则更新values保存的时间为当前时间
        * @param reconnectTimePeriod
        * @return 如果当前时间减去values保存的时间大于给定的时间间隔返回真，否则返回非真
        */
       public boolean compareAndSetTimeStamp(int reconnectTimePeriod) {
           while (true) {
               Pair oldv = values.get();
               long time = System.currentTimeMillis();
               if ((time - oldv.timeStamp) < reconnectTimePeriod) {
                   return false;
               }
               Pair newv = new Pair(oldv.qLength, time);
               if (values.compareAndSet(oldv, newv)) {
                   return true;
               }
           }
       }
   }
   
   
2. Ejb3ClientProxy类，调用ejb方法，支持自动重连同步
   
   import com.xued.clusteredejb.ExRemote;
   import java.util.Properties ;
   import javax.naming.Context;
   import javax.naming.InitialContext ;
   import javax.naming.NamingException;
   import org.jboss.remoting.CannotConnectException ;
   
   public class Ejb3ClientProxy {
   
       private ExRemote exBean;
       private Context ctx;
       private ConnectorStatusPair connectorStatus = new ConnectorStatusPair(0, 0);
   
       public Ejb3ClientProxy(String hostUrl) {
           try {
               Properties props = new Properties();
               props.put("java.naming.factory.initial", "org.jnp.interfaces.NamingContextFactory");
               props.put("java.naming.factory.url.pkgs", "org.jboss.naming:org.jnp.interfaces");
               props.put("java.naming.provider.url", hostUrl);
               props.put("jnp.socketFactory", "org.jnp.interfaces.TimedSocketFactory ");
               props.put("jnp.timeout", "10000");
               props.put("jnp.sotimeout", "10000");
               this.ctx = new InitialContext(props);
               getExBeanInstance();
           } catch (NamingException ex) {
               System.out.println("EJB3 client initialize failed!");
           }
       }
   
       public String invoke(String name) {
           if (connectorStatus.getQLength() != 0) {
               return "not alive";
           }
           String res = null;
           try {
               res = exBean.invoke(name);
           } catch (CannotConnectException ex) {
               if (isNeedReconnect()) {
                   res = refreshConnection(name);
               } else {
                   res =  ex.getClass().getName() + ": " + ex.getMessage();
               }
               connectorStatus.decrementAndGetQLength ();
           } catch (Exception ex) {
               res = ex.getClass ().getName() + ": " + ex.getMessage();
           }
           return res;
       }
   
       private boolean isNeedReconnect(){
           return connectorStatus.incrementAndGetQLength() == 1 &&
                   connectorStatus.compareAndSetTimeStamp(60000); //间隔60秒重连一次
       }
      
      
       private void getExBeanInstance() throws NamingException {
           this.exBean = (ExRemote) this.ctx.lookup("ExBean/remote");
       }
   
       private String refreshConnection(String name) {
           String res;
           try {
               getExBeanInstance();
               res = exBean.invoke(name+" Server was crashed");
           } catch (NamingException ex1) {
               System.out.println("reconnect failed");
               res = "error occured";
           }
           return res;
       }
   }