dao.java

本例采用sql server数据库。基于JBuilder的tomcat上运行。访问数据库基于struts的datasources.里面有详细的操作和设置说明。

//---------------------------------------------------------
// Application: Gsm of Application
// Author     : esingle
// File       : DAO.java
//
// Copyright 2004 landsoft corp
// Generated at Wed Mar 10 15:35:57 CST 2004
// created by 曹广鑫
// mailto:[e-mail]
//---------------------------------------------------------

package com.landsoft.gsm.dao;

import java.io.*;
import java.sql.*;
import java.util.*;
import javax.sql.*;

import java.lang.IllegalAccessException;
import java.lang.reflect.InvocationTargetException;

import org.apache.commons.beanutils.BeanUtils;

public class DAO {

  protected DataSource ds;

  protected void populate(Object bean, ResultSet rs) throws SQLException {
    ResultSetMetaData metaData = rs.getMetaData();
    int ncolumns = metaData.getColumnCount();

    HashMap properties = new HashMap();
    // Scroll to next record and pump into hashmap
    for (int i=1; i<=ncolumns ; i++) {
      properties.put(sql2javaName(metaData.getColumnName(i)), rs.getString(i));
    }
    // Set the corresponding properties of our bean
    try {
      BeanUtils.populate(bean, properties);
    } catch (InvocationTargetException ite) {
      throw new SQLException("BeanUtils.populate threw " + ite.toString());
    } catch (IllegalAccessException iae) {
      throw new SQLException("BeanUtils.populate threw " + iae.toString());
    }
  }

  public int getSize(String tableName, String condition) throws SQLException {
    Connection conn = null;
    PreparedStatement pstmt = null;
    ResultSet rs = null;
    try {
      String sql = "SELECT count(*) FROM "+tableName+" "+condition;
      conn = ds.getConnection();
      pstmt = conn.prepareStatement(sql);
      rs = pstmt.executeQuery();
      rs.next();
      int size = rs.getInt(1);
      close(rs);
      close(pstmt);
      return size;
    } catch (SQLException sqle) {
      close(rs);
      close(pstmt);
      rollback(conn);
      sqle.printStackTrace();
      throw sqle;
    } finally {
    	close(conn);
    }
  }

  public DAO(DataSource ds) {
  	this.ds = ds;
  }

  public void setDataSource(DataSource ds) {
    this.ds = ds;
  }

  protected void close(ResultSet rs) {
    if (rs != null) {
    	try {
    		rs.close();
    	} catch (SQLException e) {
    	}
    	rs = null;
    }
  }

  protected void close(PreparedStatement pstmt) {
    if (pstmt != null) {
    	try {
    		pstmt.close();
    	} catch (SQLException e) {
    	}
    	pstmt = null;
    }
  }

  protected void close(Connection conn) {
    if (conn != null) {
    	try {
    		conn.close();
    	} catch (SQLException e) {
    		e.printStackTrace();
    	}
    	conn = null;
    }
  }

  protected void rollback(Connection conn) {
    if (conn != null) {
    	try {
    		conn.rollback();
    	} catch (SQLException e) {
    		e.printStackTrace();
    	}
    	conn = null;
    }
  }

  protected static String java2sqlName(String name) {
    String column = "";
    for (int i = 0; i < name.length(); i++) {
      if (i < name.length() - 1 && (name.charAt(i) >= 'a' && name.charAt(i) <= 'z') &&
          (name.charAt(i + 1) >= 'A' && name.charAt(i + 1) <= 'Z')) {
        column += name.charAt(i) + "_";
      } else {
        column += name.charAt(i);
      }
    }
    return column.toLowerCase();
  }

  protected static String sql2javaName(String name) {
    String column = "";
    for (int i = 0; i < name.length(); i++) {
      if (name.charAt(i) == '_') {
        column += ++i<name.length()?String.valueOf(name.charAt(i)).toUpperCase():"";
      } else {
        column += name.charAt(i);
      }
    }
    return column;
  }


}