java jdbc 封装。。

JDBC工具类。。。
package it.cast.jdbcutils;

import java.io.InputStream;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.Properties;

public class JdbcUtils {
    private  static String JDriver=null;
    private  static String connectDB=null;
    private  static String username=null;
    private  static String password=null;

        static {
        try {

            InputStream in =null; 

            in= JdbcUtils.class.getClassLoader().getResourceAsStream("db.properties");

            Properties prop=new Properties();

            prop.load(in);

            JDriver=prop.getProperty("JDriver");

            connectDB=prop.getProperty("connectDB");
            username=prop.getProperty("username");
            password=prop.getProperty("password");

            Class.forName(JDriver);
            System.out.println("数据库连接成功");
        }
        catch (Exception e)
        {
            throw new ExceptionInInitializerError("连接失败");
        }
}

public static Connection getConnection() throws SQLException
    {
        return DriverManager.getConnection(connectDB,username,password);
    }
    public static void release (Connection conn,Statement st,ResultSet rs)
    {
        if(rs!=null)
        {
            try
            {
                rs.close();
            }
            catch(Exception e)
            {
                e.printStackTrace();
            }
        }
        if(st!=null)
        {
            try
            {
                st.close();
            }
            catch(Exception e)
            {
                e.printStackTrace();
            }
        }
        if(conn!=null)
        {
            try
            {
                conn.close();
            }
            catch(Exception e)
            {
                e.printStackTrace();
            }
        }
        System.out.println("数据库已经断开连接");
    }
    //增删改方法。
    public static void query(String sql,Object params []) throws SQLException
    {
        Connection conn =null;
        PreparedStatement st=null;
        ResultSet rs = null;
        conn = JdbcUtils.getConnection();
        try
        {
            //获取数据连接
            conn = JdbcUtils.getConnection();
            //获取数据库对象并对SQL进行预编译
            st =conn.prepareStatement(sql);
            //获取传进来的SQL，和传进来的参数。并进行赋值。
            for(int i=;i<params.length;i++)
            {
                st.setObject(i+,params[i]);
                System.out.println(params[i]);
            }
            //执行
            st.executeUpdate();

        }
        finally
        {
            //释放
            JdbcUtils.release(conn, st, rs);
        }

    }

}

//实体类。
package in.cast.dao;

public class data {
    private String date;
    private Integer num;
    public   data (String date,Integer num)
    {
        this.date=date;
        this.num=num;
    }
    public String getDate() {
        return date;
    }
    public void setDate(String date) {
        this.date = date;
    }
    public int getNum() {
        return num;
    }
    public void setNum(Integer num) {
        this.num = num;
    }
    public String toString()
    {
        return date+" : "+num ;
    }
}

　　

测试：

package in.cast.dao;
import it.cast.jdbcutils.JdbcUtils;
import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.Statement;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import java.util.Set;
public class JDBC_TEST {
    public static void main (String [] args) throws Exception
    {

        JDBC_TEST T=new JDBC_TEST();

        HashMap<Integer,data> m=T.insert();

        DataSearch(m);

    }
    public static void DataSearch(HashMap<Integer, data> m) {
        Set<Map.Entry<Integer,data>> entryset=m.entrySet();

        Iterator <Map.Entry<Integer,data>>it=entryset.iterator();

        while(it.hasNext())
        {
            Map.Entry<Integer,data> mp=it.next();
            System.out.println(mp.getKey()+" : "+mp.getValue());

        }
    }
    public  HashMap<Integer,data> insert() throws Exception
    {
        HashMap<Integer,data> mp = new HashMap<Integer,data>();
        String s1;
        Integer s2;
        Connection conn=null;
        Statement st=null;
        ResultSet rs=null;
        Integer iCount=0;
        try
        {
            //获取数据库连接
            conn=JdbcUtils.getConnection();

            //返回一个statement,作用于发送SQL语句 。
            st = conn.createStatement();
            //SQL 语句
            String sql=" select * from tt ; " ;
            //返回一个数据集
            rs = st.executeQuery(sql) ;  //update
            //循环
            while(rs.next())
            {
                iCount++;
                s1=rs.getString("日期");//等同getObject(column_name)
                s2=Integer.parseInt(rs.getString("存入"));
                mp.put(iCount,new data(s1,s2));

            }
        }
        catch (Exception e)
        {
            e.printStackTrace();
        }
        finally
        {
             JdbcUtils.release(conn,st, rs);
        }

        return mp;
    }
    

配置文件：

JDriver=com.microsoft.sqlserver.jdbc.SQLServerDriver
connectDB=jdbc:sqlserver://127.0.0.1:1433;DatabaseName=test
username=sa
password=123

JDBC。

package in.cast.dao;
import java.sql.*;
public class test1{
    public static void main(String[] args) {
        //com.microsoft.sqlserver.jdbc.SQLServerDriver 2008
　　　　 String JDriver="com.microsoft.sqlserver.jdbc"; 2005
        String connectDB="jdbc:sqlserver://127.0.0.1:1433;DatabaseName=test";

        try{
            Class.forName(JDriver);//通过反射加载驱动。
        }catch(ClassNotFoundException e)
        {  

            System.out.println("数据库连接异常");  

           //这里可以抛出一个自定义异常
  }
  System.out.println("锟斤拷菘锟斤拷锟缴癸拷");  

  try{
      String user="sa";
      String password="123";
      Connection con=DriverManager.getConnection(connectDB,user,password);

      Statement stmt=con.createStatement();

       //建表
      String query="create table TABLE1(ID NCHAR(2),NAME NCHAR(10))";
      //提交语句
      stmt.executeUpdate(query);

      String a1="INSERT INTO TABLE1 VALUES('1','a')";
      String a2="INSERT INTO TABLE1 VALUES('2','b')";
      String a3="INSERT INTO TABLE1 VALUES('3','c')";
      stmt.executeUpdate(a1);
      stmt.executeUpdate(a2);
      stmt.executeUpdate(a3);  

      ResultSet rs=stmt.executeQuery("SELECT * FROM TABLE1");

      while(rs.next()){  

          System.out.println(rs.getString("ID")+"\t"+rs.getString("NAME"));
      }  

     //从建表到插入数据到查询 。仅为熟悉语句。

      stmt.close();
      con.close();
  }catch(SQLException e){
      e.printStackTrace();  

      System.exit(0);
    }
    }
}