关于JDBC的封装

来源：互联网发布：迷宫的生成算法编辑：程序博客网时间：2024/06/06 08:49
package JDBC_Example;import java.sql.*;import java.util.ArrayList;import java.util.HashMap;import java.util.List;import java.util.Map;/** * Created by john on 2016/7/3. * @author zzy */class ConnectionZzy{    //drivername    private static final String DRIVERNAME = "com.mysql.jdbc.Driver";    //url    private static final String URL = "jdbc:mysql://localhost:3306/jdbc_example";    //username    private static final String USERNAME = "root";    //password    private static final String USERPASSWORD = "";    private Connection connnection = null;    private PreparedStatement preparedStatement = null;    private ResultSet resultSet = null;    static{        try {            Class.forName(DRIVERNAME);        } catch (ClassNotFoundException e) {            System.out.println(e.getMessage());        }    }    private Connection getConnection() {        try {            connnection = DriverManager.getConnection(URL,USERNAME,USERPASSWORD);        } catch (SQLException e) {            System.out.println(e.getMessage());        }        return connnection;    }    //select something    private ResultSet executeQuery(String sql,Object[] params) {        try {            connnection = this.getConnection();            preparedStatement = connnection.prepareStatement(sql);            if(params!=null){                for(int i=0;i<params.length;i++){                    preparedStatement.setObject(i+1,params[i]);                }            }            resultSet=preparedStatement.executeQuery();        } catch (SQLException e) {            System.out.println(e.getMessage());        }        return resultSet;    }    //select something return a arraylist    List<Object> excuteQuerys(String sql,Object[] params) {        List<Object> list = new ArrayList<>();        ResultSetMetaData rsmd;        int columnCount;        ResultSet rs = executeQuery(sql,params);        try {            rsmd = rs.getMetaData();            columnCount = rsmd.getColumnCount();//表的列数            while (rs.next()) {                Map<String,Object> map=new HashMap<>();                for(int i=1;i<=columnCount;i++){                    map.put(rsmd.getColumnLabel(i),rs.getObject(i));                }                list.add(map);            }        } catch (SQLException e) {            System.out.println(e.getMessage());        } finally {            closeAll();        }        return list;    }    //update something,insert something,delete something    int executeUpdate(String sql,Object[] params) {        int affectedLine = 0;        try {            connnection = this.getConnection();            preparedStatement = connnection.prepareStatement(sql);            if(params!= null) {                for(int i=0;i<params.length;i++){                    preparedStatement.setObject(i+1,params[i]);                }            }            affectedLine = preparedStatement.executeUpdate();        } catch (SQLException e) {            System.out.println(e.getMessage());        } finally {            closeAll();        }        return affectedLine;    }    //colse something    private void closeAll() {        if (resultSet != null) {            try {                resultSet.close();            } catch (SQLException e) {                System.out.println(e.getMessage());            }        }        if (preparedStatement != null) {            try {                preparedStatement.close();            } catch (SQLException e) {                System.out.println(e.getMessage());            }        }        if (connnection != null) {            try {                connnection.close();            } catch (SQLException e) {                System.out.println(e.getMessage());            }        }    }}
0 0