2011年9月2日

ibatis分页<一>

package com.lxy.dialect;
public abstract interface Dialect {
public boolean supportLimit();
public String getLimitString(String sql,boolean hasoffset);
public String getLimitString(String sql,int offset,int limit);
}


package com.lxy.dialect;
public class MyDialect implements Dialect {
protected static final String SQL_END_DELIMITER = ";";
public String getLimitString(String sql, boolean hasoffset) {
return new StringBuffer(sql.length() + 20).append(trim(sql)).append(
hasoffset ? "limit ?,?" : "limit ?").append(SQL_END_DELIMITER)
.toString();
}
public String getLimitString(String sql, int offset, int limit) {
sql = trim(sql);
StringBuffer sb = new StringBuffer(sql.length() + 20);
sb.append(sql);
if (offset > 0) {
sb.append("limit").append(offset).append(',').append(limit).append(
";");
} else {
sb.append("limit").append(limit).append(";");
}
return sb.toString();
}
public boolean supportLimit() {
return true;
}
private String trim(String sql) {
sql = sql.trim();
if (sql.endsWith(";")) {
sql = sql.substring(0, sql.length() - 1 - ";".length());
}
return sql;
}
}

posted @ 2011-09-14 19:11 crazy-李阳 阅读(200) | 评论 (0) | 编辑 收藏

线程池代码

ThreadPoolManager

package com.threadpool.test;
import java.util.LinkedList;
import java.util.Queue;
import java.util.concurrent.ArrayBlockingQueue;
import java.util.concurrent.Executors;
import java.util.concurrent.RejectedExecutionException;
import java.util.concurrent.RejectedExecutionHandler;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.ScheduledFuture;
import java.util.concurrent.ThreadPoolExecutor;
import java.util.concurrent.TimeUnit;

import org.omg.CORBA.TIMEOUT;

import com.nio.test.ReadFileThread;

public class ThreadPoolManager {

    private static ThreadPoolManager tpm = new ThreadPoolManager();

    // 线程池最小线程数
    private final static int MIN_SIZE = 4;
    // 线程池最大线程数
    private final static int MAX_SIZE = 10;
    // 线程池维护线程允许的空闲限制
    private final static int KEEP_ACTIVE_TIME = 0;
    // 线程池用的缓冲队列大小
    private final static int WORK_QUEUE_SIZE = 10;
    // 消息缓冲队列
    Queue queue = new LinkedList();
    
    final Runnable accessBuffeThread = new Runnable()
    {

        public void run() {
            
            if( hasMoreAcquire() ){
                
                String msg = ( String ) queue.poll();
                Runnable task = new AccessDBThread( msg );
                threadpool.execute( task );
            }
        }
        
    };
    // 无法由 ThreadPoolExecutor 执行的任务的处理程序
    final RejectedExecutionHandler handler = new RejectedExecutionHandler()
    {

        public void rejectedExecution(Runnable r, ThreadPoolExecutor executor) {
            // TODO Auto-generated method stub
            System.out.println(((AccessDBThread )r).getMsg()+"消息放入队列中重新等待执行");
            queue.offer((( AccessDBThread ) r ).getMsg() );
        }
        
    };
    
    final ThreadPoolExecutor threadpool = new ThreadPoolExecutor(MIN_SIZE, MAX_SIZE, KEEP_ACTIVE_TIME, TimeUnit.SECONDS, new ArrayBlockingQueue(WORK_QUEUE_SIZE),this.handler);
    
    // 调度线程池

    final ScheduledExecutorService scheduler = Executors.newScheduledThreadPool( 1 );

    final ScheduledFuture taskHandler = scheduler.scheduleAtFixedRate(accessBuffeThread, 0, 1, TimeUnit.SECONDS);
    
    public static ThreadPoolManager newinstance()
    {
        return tpm;
    }
    
    private ThreadPoolManager (){}
    
    
    private boolean hasMoreAcquire()
    {
        return !queue.isEmpty();
    }
    
    public void addLogMsg(String msg)
    {
     Runnable task = new AccessDBThread(msg);
     threadpool.execute(task);
    }
}
AccessDBThread
package com.threadpool.test;

public class AccessDBThread implements Runnable{

    private String msg;
    public String getMsg() {
        return msg;
    }
    public void setMsg(String msg) {
        this.msg = msg;
    }
    
    public AccessDBThread(){
        super();
    }
    
    public AccessDBThread(String msg)
    {
        this.msg=msg;
    }
    public void run() {
        // TODO Auto-generated method stub
        System.out.println("Added the message: "+msg+" into the Database");
    }

    
}

测试类：
package com.threadpool.test;


public class TestDriver {

    ThreadPoolManager tpm = ThreadPoolManager.newinstance();
    
    public void addMsg(String msg)
    {
        tpm.addLogMsg(msg);
    }
    public static void main(String[] args) {
        for(int i=0;i<100;i++)
        {
            new TestDriver().addMsg(Integer.toString(i));
        }
    }
}

posted @ 2011-09-02 15:20 crazy-李阳 阅读(408) | 评论 (0) | 编辑 收藏

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