databaseconnection.java

一个完整的办公资源管理系统

package org.qiming.tianke.common;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

public class DataBaseConnection implements DataBaseSource {
	
	public Connection aConnection=null;
	public Statement aStatement=null;
	public ResultSet aResult=null;
	
	public DataBaseConnection(){
		try {
			Class.forName(driver).newInstance();
		} catch (InstantiationException e) {
			e.printStackTrace();
		} catch (IllegalAccessException e) {
			e.printStackTrace();
		} catch (ClassNotFoundException e) {
			e.printStackTrace();
		}
	}
		
	public void getConnection(){		
		try {
			aConnection=DriverManager.getConnection(url,username,password);
		} catch (SQLException e) {
			e.printStackTrace();
		}		
	}
	
	public void getStatement(){		
		try {
			if(aConnection==null||aConnection.isClosed()){
				getConnection();
			}
			aStatement=aConnection.createStatement();
		} catch (SQLException e) {
			e.printStackTrace();
		}
	}
	

	public ResultSet doQuery(String sql){
		getStatement();
		try {
			aResult=aStatement.executeQuery(sql);
		} catch (SQLException e) {
			e.printStackTrace();
		}
		return aResult;
	}
	

	public int countSumAnnal(String sql){
		int count=0;
		getStatement();
		try {
			aResult=aStatement.executeQuery(sql);
			if(aResult.next())
			{
				count=Integer.parseInt(aResult.getString(1));
			}
		} catch (SQLException e) {
			e.printStackTrace();
		}finally{
			this.doClose();
		}
		return count;
	}
	

	public String getKey(String sql){
		String key="";
		getStatement();
		try {
			aResult=aStatement.executeQuery(sql);
			
			if(aResult.next()){
				int i=Integer.parseInt(aResult.getString(1))+1;
				key=String.valueOf(i);
			}
		} catch (SQLException e) {
			e.printStackTrace();
		}finally{
			this.doClose();
		}
		return key;
	}
	

//	public boolean  doUpdate(String sql){
//		 boolean is=false;
//		  getStatement();
//		try {
//	        int i1=aStatement.executeUpdate(sql);
//	         if(i1==1){
//	              is=true;
//	         }
//		} catch (SQLException e) { 
//			e.printStackTrace();
//		}finally{
//			this.doClose();
//		}
//		return is;
//	}	


//	public boolean doDelete(String sql){
//		boolean is=false;
//		
//		getStatement();
//		try {
//			int i2=aStatement.executeUpdate(sql);
//			if(i2==1){
//				is=true;
//			}			
//		} catch (SQLException e) {
//			e.printStackTrace();
//		}finally{
//			this.doClose();
//		}
//		return is;
//	}

//	public boolean doInsert(String sql){
//		boolean is=false;
//		getStatement();
//		try {
//			int i3=aStatement.executeUpdate(sql);
//			if(i3==1){
//				is=true;
//			}			
//		} catch (SQLException e) {
//			e.printStackTrace();
//		}finally{
//			this.doClose();
//		}
//		return is;
//	}
	
	
	public boolean doExecute(String sql){
		boolean is=false;
		getStatement();
		try {
			is=aStatement.execute(sql);			
			if(is){
				return is;
			}else{  
				is=false;
			}
		} catch (SQLException e) {
			e.printStackTrace();
		}finally{
			this.doClose();
		}
		return is;
	}
	
	
	public void doClose(){
		if(aResult!=null)
			try {
				aResult.close();
			} catch (SQLException e) {
				e.printStackTrace();
			}
		if(aStatement!=null)
			try {
				aStatement.close();
			} catch (SQLException e) {
				e.printStackTrace();
			}
		try {
			if(aConnection!=null||!aConnection.isClosed())
				try {
					aConnection.close();
				} catch (SQLException e) {
					e.printStackTrace();
				}
		} catch (SQLException e) {
			e.printStackTrace();
		}		
	}	
}