JDBC与JNDI

自从弄了框架之后，以前的一些东西有点点生疏了。先总结下。

java连接数据库有4中方式
1.JDBC-ODBC桥+ODBC驱动
2.本地API
3.JDBC网络纯JAVA驱动
4.本地协议纯java驱动程序

首先从最早接触到的纯JBDC的那种DAO层写法开始。
一开始是这样写DAO层的数据库连接的。
1
首先从最早接触到的纯JBDC的那种DAO层写法开始。
一开始是这样写DAO层的数据库连接的。

package com.dao;

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

public class BaseDao {
	private static Connection con = null;
	private final static String url = "jdbc:mysql://localhost:3306/test";// 数据库连接名
	private final static String usrName = "root";// 用户名
	final static private String pwd = "lohas";// 密码
	final static  private String driver = "com.mysql.jdbc.Driver";
	public static   Connection getConnection() {
		try {
			Class.forName(driver);
		} catch (ClassNotFoundException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		try {
			con = DriverManager.getConnection(url, usrName, pwd);
		} catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		return con;
	}

	public void closeAll(ResultSet set, PreparedStatement ps, Connection con) {

		try {
			if (set != null) {
				set.close();
			}
			if (ps != null) {
				ps.close();
			}
			if (con != null) {
				con.close();
			}
		} catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
	}

	public int executeSql(String sql, Object[] param) {//执行SQL语句
		Connection con = getConnection();
		PreparedStatement ps = null;
		int count = 0;
		try {
			ps = con.prepareStatement(sql);
			if (param != null) {
				for (int i = 0; i < param.length; i++) {
					ps.setObject(i + 1, param[i]);
				}
			}
			count = ps.executeUpdate();// 执行sql语句
		} catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		closeAll(null, ps, con);
		return count;
	}
	
	public ResultSet querySql(String sql){//查询
		con = getConnection();
		ResultSet set = null;
		PreparedStatement ps = null;
		try {
			ps = con.prepareStatement(sql);
		} catch (SQLException e1) {
			// TODO Auto-generated catch block
			e1.printStackTrace();
		}
		 try {
			set = ps.executeQuery(sql);
		} catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		//closeAll(set, ps, con);
		return set;
	}
	
	public ResultSet querySql(String sql,Object[] str){//查询
		con = getConnection();
		ResultSet set = null;
		PreparedStatement ps = null;
		try {
			ps = con.prepareStatement(sql);
			if (str != null) {
				for (int i = 0; i < str.length; i++) {
					ps.setObject(i + 1, str[i]);
				}
			}
		} catch (SQLException e1) {
			// TODO Auto-generated catch block
			e1.printStackTrace();
		}
		 try {
			set = ps.executeQuery();
		} catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		//closeAll(set, ps, con);
		return set;
	}
	public ResultSet getOneIntence(String sql,Object obj){
		Connection con = getConnection();
		PreparedStatement ps = null;
		ResultSet set = null;
		try {
			ps = con.prepareStatement(sql);

			ps.setObject(1, obj);
			set = ps.executeQuery();// 执行sql语句
		} catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		//closeAll(null, ps, con);
		return set;
	}

}

这种写法没有写连接管理类，并且都是硬编码的方式，传统的操作ResultSet PreparedStatement  Connection 这几个接口，方法还是不够通过。



那个时候的JNDI是这样写的

Web.xml
  <resource-ref>

    <res-ref-name> jdbc/JNDI6 </res-ref-name>

    <res-type> javax.sql.DataSource </res-type>

    <res-auth> Container </res-auth>

  </resource-ref>

package com.dao;

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

import javax.naming.Context;
import javax.naming.InitialContext;
import javax.naming.NamingException;
import javax.sql.DataSource;

public class BaseDao {
	/**
	 * 采用JNDI数据库连接池
	 */
	private static Connection con;

	public static Connection getConnection() {
		/**
		 * 通过JNDI获得连接对象
		 */
		Context ic=null;
		try {
			ic = new InitialContext();
			DataSource source = (DataSource) ic.lookup("java:comp/env/jdbc/JNDI6");
			con = source.getConnection();
		} catch (NamingException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}finally{
			try {
				ic.close();
			} catch (NamingException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
		}return con;
	}
	
	/**
	 * 采用JNDI方式connection 不用关  容器会自动回收
	 * @param set
	 * @param sta
	 */
	public static void closeAll(ResultSet set ,Statement sta){
		if(set!=null){
			try {
				set.close();
			} catch (SQLException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
		}
		if(sta!=null){
			try {
				sta.close();
			} catch (SQLException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
		}
	} 
}

再后来有了配置文件，读取配置文件的代码如下：

url = jdbc:mysql://localhost:3306/shopdb
usrName = admin
pwd = admin
driver = com.mysql.jdbc.Driver


package com.Properties;

import java.io.IOException;
import java.io.InputStream;
import java.util.Properties;

public class Env extends Properties {
	/**
	 * 
	 */
	private static final long serialVersionUID = 1L;
	private static Env instance;

	public static Env getInstance() {
		if (instance != null) {
			return instance;
		} else {
			mackInstance();
			return instance;
		}
	}

	private static synchronized void mackInstance() {
		// TODO Auto-generated method stub
		if (instance == null) {
			instance = new Env();
		}
	}

	private Env() {
		/**
		 * 从输入流中读取属性列表（键和元素对）。输入流按 load(Reader) 中所指定的、简单的面向行的格式，并假定使用 ISO 8859-1
		 * 字符编码；即每个字节都是 Latin1 字符。对于非 Latin1 的字符和某些特殊字符，可以使用 Unicode
		 * 转义以键和元素的形式来表示它们。
		 */
		InputStream in = this.getClass().getResourceAsStream("/db.properties");
		try {
			load(in);// 父类方法
			in.close();
		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
	}
}



package com.dao;

import com.Properties.Env;

public class TestProperties {
	public static void main(String[] args) {
		String name = Env.getInstance().getProperty("url");//读取配置文件
		System.out.println(name);
	}
}

再后来

package com.oh.util;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;

import javax.servlet.jsp.jstl.sql.Result;
import javax.servlet.jsp.jstl.sql.ResultSupport;

public class SqlCommentBean {
	/**
	 * 操纵数据库工具类
	 */
	private Connection connection = ConnectionManager.getConnection();// 连接类
	private String sql;// sql语句
	private Object[] sqlParams;// sql语句参数数组

	public SqlCommentBean(String sql, Object[] sqlParams) {
		/**
		 * 带有sql参数构造器
		 */
		super();
		this.sql = sql;
		this.sqlParams = sqlParams;
	}

	public SqlCommentBean(String sql) {
		/**
		 * 不带有sql参数构造器
		 */
		super();
		this.sql = sql;
	}
	/**
	 * 执行查询
	 */
	public Result executeQuery() {
		Result result = null;
		ResultSet set = null;
		PreparedStatement ps = null;
		try {
			ps = connection.prepareStatement(sql);
		} catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		if (sqlParams != null && sqlParams.length > 0) {
			try {
				setSqlParams(ps, sqlParams);
				set = ps.executeQuery();
			} catch (SQLException e1) {
				// TODO Auto-generated catch block
				e1.printStackTrace();
			}
		} else {
			try {
				set = ps.executeQuery();
			} catch (SQLException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
		}
		result = ResultSupport.toResult(set);// 将resultset转化为result
		ConnectionManager.closeAll(ps, set);
		return result;
	}

	/**
	 * 执行增删改
	 * 
	 * @return
	 */
	public int executeUpdate() {
		PreparedStatement ps = null;
		int rows = 0;
		try {
			ps = connection.prepareStatement(sql);
		} catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		if (sqlParams != null && sqlParams.length > 0) {
			try {
				setSqlParams(ps, sqlParams);
				rows = ps.executeUpdate();
			} catch (SQLException e1) {
				// TODO Auto-generated catch block
				e1.printStackTrace();
			}
		} else {
			try {
				rows = ps.executeUpdate();
			} catch (SQLException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
		}
		try {
			ps.close();
		} catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		return rows;

	}

	/**
	 * 设置sql语句
	 * 
	 * @param sql
	 */
	public void setSql(String sql) {
		this.sql = sql;
	}

	/**
	 * 设置sql语句参数 内部方法
	 * 
	 * @param sqlParams
	 */
	private void setSqlParams(PreparedStatement ps, Object[] sqlParams) {
		if (sqlParams != null) {
			for (int i = 0; i < sqlParams.length; i++) {
				try {
					ps.setObject(i + 1, sqlParams[i]);
				} catch (SQLException e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				}
			}
		}
	}
	
	
	private void setDarkSqlParams(PreparedStatement ps, Object[] sqlParams){
		/**
		 * 设置模糊参数
		 */
		if (sqlParams != null) {
			for (int i = 0; i < sqlParams.length; i++) {
				try {
					if(sqlParams[i] instanceof Integer){//如果是具体的数值类型
						ps.setObject(i + 1, sqlParams[i]);
					}else{
						if(!"".equals(sqlParams[i])){
						ps.setObject(i + 1, "%"+sqlParams[i]+"%");
						}
					}
					
				} catch (SQLException e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				}
			}
		}
	}
	public  Result darkQuery(){
		/**
		 * 执行模糊查询
		 */
		Result result = null;
		ResultSet set = null;
		PreparedStatement ps = null;
		try {
			ps = connection.prepareStatement(sql);
		} catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		if (sqlParams != null && sqlParams.length > 0) {
			try {
				setDarkSqlParams(ps, sqlParams);
				set = ps.executeQuery();
			} catch (SQLException e1) {
				// TODO Auto-generated catch block
				e1.printStackTrace();
			}
		} else {
			try {
				set = ps.executeQuery();
			} catch (SQLException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
		}
		result = ResultSupport.toResult(set);// 将resultset转化为result
		ConnectionManager.closeAll(ps, set);
		return result;
	}
}