connmanager.java

java版源代码,里面包含很多源代码,大家可以看看.

package com.trulytech.mantis.system;

import java.sql.Connection;
import java.sql.DriverManager;
import javax.naming.Context;
import javax.naming.InitialContext;
import javax.sql.DataSource;
import java.sql.SQLException;

/**
 * <p>Title: ConnManager</p>
 * <p>Description: 数据库连接管理</p>
 * <p>Copyright: Copyright (c) 2002</p>
 * <p>Company: trulytech</p>
 * @author WangXian
 * @version 1.2
 */

public class ConnManager {

//是否已经初始化
  public static boolean isInited = false;
//数据源
  private static DataSource ds = null;
//JDBC属性
  private static java.util.Properties props = null;

  /**
   * 获得数据库连接
   * @return Connect 数据库连接
   * @throws Exception
   */
  public static Connection getConnection() throws Exception {

    Connection conn = null;

    if (!isInited)
      throw new Exception("Database Connection has not been initilized!");
    try {
        //如果是native的连接池
      if (Properties.isConnectPool &&
          Properties.PoolProvider.equalsIgnoreCase("native")) {

        conn = PoolManager.getInstance().getConnection();
        if (conn == null)throw new ConnectionException();
        return conn;
      }
      //如果使用tomcat的连接池
      else if (Properties.isConnectPool &&
               Properties.PoolProvider.equalsIgnoreCase("tomcat")) {
        conn = ds.getConnection();
        if (conn == null)throw new ConnectionException();
        return conn;
      }
      //如果使用非tomcat的连接池
      else if (Properties.isConnectPool &&
               !Properties.PoolProvider.equalsIgnoreCase("tomcat")) {
        conn = ds.getConnection(Properties.UserName, Properties.Password);
        if (conn == null)throw new ConnectionException();
        return conn;
      }
      //如果不使用连接池
      else {
        conn = DriverManager.getConnection(Properties.JDBCURL, props);
        if (conn == null)throw new ConnectionException();
        return conn;
      }

    }
    catch (Exception e) {
      logWriter.Error("获取数据库连接失败-" + e.toString());
      throw e;
    }

  }

  /**
   * 关闭数据库连接
   * @param conn Connection 连接
   * @throws SQLException
   */
  public static void closeConnection(Connection conn) throws SQLException {
    if (conn != null) {
      //如果使用native Connection Pool
      if (Properties.isConnectPool &&
          Properties.PoolProvider.equalsIgnoreCase("native")) {
        PoolManager.getInstance().freeConnection(conn);
      }
      else {

        if (!conn.isClosed()) {
          conn.close();
          conn = null;
        }

      }
    }
  }

  /**
   * 释放所有数据库连接
   */
  public static void releaseConnection() {
    if (Properties.isConnectPool &&
        Properties.PoolProvider.equalsIgnoreCase("native")) {
      PoolManager.getInstance().release();
      logWriter.Info("连接池释放连接成功");

    }
  }

  /**
   * 初始化数据库连接
   * @throws Exception
   */
  protected static void init() throws Exception {
    if (isInited)
      return;
    try {
      props = new java.util.Properties();
      props.put("characterEncoding", Properties.Charset);
      props.put("useUnicode", Properties.isUnicode);
      props.put("user", Properties.UserName);
      props.put("password", Properties.Password);
      //如果使用native Connection Pool
      if (Properties.isConnectPool &&
          Properties.PoolProvider.equalsIgnoreCase("native")) {
        logWriter.Debug("使用内部连接池");
        Class.forName(Properties.JDBCClass);
        logWriter.Info("数据库连接初始化成功");
        isInited = true;
      }
      //如果使用Weblogic连接池
      else if (Properties.isConnectPool &&
               !Properties.PoolProvider.equalsIgnoreCase("native")) {
        if (!Properties.PoolProvider.equalsIgnoreCase("tomcat")) {
          logWriter.Debug("使用外部连接池");
          Context ctx = new InitialContext();
          ds = (DataSource) ctx.lookup(Properties.DataSource);
        }
        //如果使用Tomcat DBCP连接池
        else {
          logWriter.Debug("使用Tomcat连接池");
          Context ctx = new InitialContext();
          Context envContext = (Context) ctx.lookup("java:/comp/env");
          ds = (DataSource) envContext.lookup(Properties.DataSource);
        }

        if (ds != null) {
          logWriter.Info("数据库连接池初始化成功");
          isInited = true;
        }
        else {
          throw new Exception("ConnectPool Established Failure!");
        }
      }
      //如果直接连接
      else {
        logWriter.Debug("使用数据库直接连接");
        Class.forName(Properties.JDBCClass);
        logWriter.Info("数据库连接初始化成功");
        isInited = true;
      }
    }
    catch (Exception e) {
      logWriter.Error("数据库连接池初始化失败-" + e.toString());
      throw e;
    }

  }

}