struts 数据源（连接池）

一。struts-config.xml加入｛

 <!-- ============ Data Source Start ================== -->
<data-sources>
  <data-source key="org.apache.struts.action.DATA_SOURCE"
   type="org.apache.commons.dbcp.BasicDataSource">
   <set-property property="autoCommit" value="true" />
   <set-property property="description"  value="mysql Data Source" />
   <set-property property="driverClassName"
    value="com.mysql.jdbc.Driver" />
   <set-property property="maxCount" value="10" />
   <set-property property="minCount" value="2" />
   <set-property property="username" value="root" />
   <set-property property="password" value="1234" />
   <set-property property="url"
    value="jdbc:mysql://127.0.0.1:3306/test" />
  </data-source>
</data-sources>
<!-- ============ Data Source End ================== -->

｝
二。新建

package com.xxx.db;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import javax.sql.DataSource;
import org.apache.struts.action.ActionServlet;
import org.apache.struts.action.PlugIn;
import org.apache.struts.config.ModuleConfig;
public class DBConn implements PlugIn {
private static DataSource dataSource = null;
private Connection conn = null;
private PreparedStatement preStmt = null;
private Statement stmt = null;
// 得到数据源
public void init(ActionServlet servlet, ModuleConfig config) {
  dataSource = (DataSource) servlet.getServletContext().getAttribute(
    "org.apache.struts.action.DATA_SOURCE");
}
public DBConn() throws SQLException {
  if (dataSource != null) {
   conn = dataSource.getConnection();
  }
}
public ResultSet executeQuery(String sql) {
  ResultSet rs = null;
  try {
   if (stmt == null) {
    stmt = conn.createStatement();
   }
   rs = stmt.executeQuery(sql);
  } catch (SQLException e) {
   e.printStackTrace();
  }
  return rs;
}
public void executeUpdate(String sql) throws SQLException {
  if (stmt == null) {
   stmt = conn.createStatement();
  }
  stmt.executeUpdate(sql);
}
public Connection getConnection() {
  return conn;
}
public void prepareStatement(String sqlStr) throws SQLException {
  preStmt = conn.prepareStatement(sqlStr);
}
public void setString(int index, String value) throws SQLException {
  preStmt.setString(index, value);
}
public void setInt(int index, int value) throws SQLException {
  preStmt.setInt(index, value);
}
public void setBoolean(int index, boolean value) throws SQLException {
  preStmt.setBoolean(index, value);
}
public void setLong(int index, long value) throws SQLException {
  preStmt.setLong(index, value);
}
public void setFloat(int index, float value) throws SQLException {
  preStmt.setFloat(index, value);
}
public void setBytes(int index, byte[] value) throws SQLException {
  preStmt.setBytes(index, value);
}
public void clearPreStmt() throws SQLException {
  preStmt.clearParameters();
  preStmt = null;
}
public ResultSet executeQuery() throws SQLException {
  if (preStmt != null) {
   return preStmt.executeQuery();
  } else {
   return null;
  }
}
public void executeUpdate() throws SQLException {
  if (preStmt != null) {
   preStmt.executeUpdate();
  }
}
public void close() {
  try {
   if (stmt != null) {
    stmt.close();
    stmt = null;
   }
   if (preStmt != null) {
    preStmt.close();
    preStmt = null;
   }
   if (conn != null) {
    conn.close();
    conn = null;
    System.out.println("**** a connection is closed ****");
   }
  } catch (Exception e) {
   System.err.println(e.getMessage());
  }
}
public void destroy() {
}
}

三。重新到struts-config.xml
在<struts-config>标签内的最下一行加入｛

<plug-in className="com.xxx.db.DBConn"></plug-in>

｝
添加插件的目的是：任何文件中都可以用到此数据源
四，使用

   Connection con =  new DBConn().getConnection();

//在Action 内测试，其它没试

参考：http://www.blogjava.net/biiau/archive/2008/04/16/193513.html