java连接mysql底层封装

package com.dao.db;

import java.sql.Connection;
import java.sql.SQLException;

/**
 * 数据库连接层MYSQL
 * @author Administrator
 *
 */
public class DBConnection {
    
    
    /**
     * 连接数据库
     * @return
     */
    public static Connection getDBConnection()
    {
        // 1. 注册驱动
        try {
            Class.forName("com.mysql.jdbc.Driver");
        } catch (ClassNotFoundException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        // 获取数据库的连接
        try {
            Connection conn  = java.sql.DriverManager.getConnection("jdbc:mysql://localhost/mysql?useUnicode=true&characterEncoding=utf-8", "root", "root");
            return conn;
        } catch (SQLException e1) {
            e1.printStackTrace();
        }
        return null;
    }
    
}

package com.dao.db;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;
import java.sql.Types;
import java.util.ArrayList;
import java.util.HashMap;

/**
 * MYSQL数据库底层封装
 * @author Administrator
 *
 */
public class DBManager {
    
    private PreparedStatement pstmt;
    private Connection conn;
    private ResultSet rs;
    

    /**
     * 打开数据库
     */
    public DBManager() {
        conn = DBConnection.getDBConnection();
    }
    
    /**
     * 执行修改添加操作
     * @param coulmn
     * @param type
     * @param sql
     * @return
     * @throws SQLException
     */
    public  boolean updateOrAdd(String[] coulmn, int[] type, String sql) throws SQLException
    {
        if(!setPstmtParam(coulmn, type, sql))
            return false;
        boolean flag = pstmt.executeUpdate()>0?true:false;
        closeDB();
        return flag;
    }
    /**
     * 获取查询结果集
     * @param coulmn
     * @param type
     * @param sql
     * @throws SQLException
     */
    public DataTable getResultData(String[] coulmn, int[] type, String sql) throws SQLException
    {
        DataTable dt = new DataTable();
        
        ArrayList<HashMap<String, String>>list = new ArrayList<HashMap<String, String>>();
        
        if(!setPstmtParam(coulmn, type, sql))
            return null;
        rs = pstmt.executeQuery();
        ResultSetMetaData rsmd = rs.getMetaData();//取数据库的列名 
        int numberOfColumns = rsmd.getColumnCount();
        while(rs.next())
        {
            HashMap<String, String> rsTree = new HashMap<String, String>(); 
            for(int r=1;r<numberOfColumns+1;r++)
             {
               rsTree.put(rsmd.getColumnName(r),rs.getObject(r).toString());
             }
            list.add(rsTree);
        }
        closeDB();
        dt.setDataTable(list);
        return dt;
    }
    
    /**
     * 参数设置
     * @param coulmn
     * @param type
     * @throws SQLException 
     * @throws NumberFormatException 
     */
    private boolean setPstmtParam(String[] coulmn, int[] type, String sql) throws NumberFormatException, SQLException
    {
        if(sql== null) return false;
        pstmt = conn.prepareStatement(sql);
        if(coulmn != null && type != null && coulmn.length !=0 && type.length !=0   )
        {        
            for (int i = 0; i<type.length; i++) {
                switch (type[i]) {
                case Types.INTEGER:
                    pstmt.setInt(i+1, Integer.parseInt(coulmn[i]));
                    break;
                case Types.BOOLEAN:
                    pstmt.setBoolean(i+1, Boolean.parseBoolean(coulmn[i]));
                    break;
                case Types.CHAR:
                    pstmt.setString(i+1, coulmn[i]);
                    break;
                case Types.DOUBLE:
                    pstmt.setDouble(i+1, Double.parseDouble(coulmn[i]));
                    break;
                case Types.FLOAT:
                    pstmt.setFloat(i+1, Float.parseFloat(coulmn[i]));
                    break;
                default:
                    break;
                }
            }
        }
        return true;
    }
    
    /**
     * 关闭数据库
     * @throws SQLException
     */
    private void closeDB() throws SQLException
    {
        if(rs != null)
        {
            rs.close();
        }
        if(pstmt != null)
        {
            pstmt.close();
        }
        if(conn != null)
        {
            conn.close();
        }
        
    }
}

package com.dao.db;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import java.util.Set;

/**
 * 数据集封装
 * @author Administrator
 *
 */
public class DataTable {
    
    public String[] column;//列字段
    public String[][] row; //行值
    public int rowCount = 0;//行数
    public int colCoun = 0;//列数
    
    
    public DataTable() {
        super();
    }
    
    public DataTable(String[] column, String[][] row, int rowCount, int colCoun) {
        super();
        this.column = column;
        this.row = row;
        this.rowCount = rowCount;
        this.colCoun = colCoun;
    }


    public void setDataTable(ArrayList<HashMap<String, String>> list) {
        rowCount = list.size();
        colCoun = list.get(0).size();
        column = new String[colCoun];
        row = new String[rowCount][colCoun];
        for (int i = 0; i < rowCount; i++) {
            Set<Map.Entry<String, String>> set = list.get(i).entrySet();
            int j = 0;
            for (Iterator<Map.Entry<String, String>> it = set.iterator(); it
                    .hasNext();) {
                Map.Entry<String, String> entry = (Map.Entry<String, String>) it
                        .next();
                row[i][j] = entry.getValue();
                if (i == rowCount - 1) {
                    column[j] = entry.getKey();
                }
                j++;
            }
        }
    }

    public String[] getColumn() {
        return column;
    }

    public void setColumn(String[] column) {
        this.column = column;
    }

    public String[][] getRow() {
        return row;
    }

    public void setRow(String[][] row) {
        this.row = row;
    }

    public int getRowCount() {
        return rowCount;
    }

    public void setRowCount(int rowCount) {
        this.rowCount = rowCount;
    }

    public int getColCoun() {
        return colCoun;
    }

    public void setColCoun(int colCoun) {
        this.colCoun = colCoun;
    }
    
    

}

package com.bussiness.test;

import java.sql.SQLException;
import java.sql.Types;

import com.dao.db.DBManager;
import com.dao.db.DataTable;

public class TestBusIness{
    
    static String searchSql = "select * from score";
    static String insertSql = "insert into score(name, age, score)values(?,?,?)";
    static String deleteSql = "delete from score where id = ?";
    static String updateSql = "update score set name = ? where id = ?";
    
    public static void main(String[] args) {
        intsertData();
        searchData();
    }
    
    private static void intsertData()
    {    
        DBManager dm = new DBManager();
        String[] coulmn = new String[]{"wyf2",  "23", "89.5"};
        int[] type = new int[]{Types.CHAR, Types.INTEGER, Types.DOUBLE};
        
        try {
            boolean flag = dm.updateOrAdd(coulmn, type, insertSql);
            if(flag)
                System.out.println("插入成功");
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }
    private static void searchData()
    {    
        DBManager dm = new DBManager();
        String[] coulmn = null;
        int[] type = null;
        
        try {
            DataTable dt = dm.getResultData(coulmn, type, searchSql);
            if(dt != null && dt.getRowCount()> 0){            
                for(int i = 0; i<dt.getRowCount(); i++)
                {
                    for(int j = 0; j<dt.getColCoun(); j++)
                    System.out.printf(dt.getRow()[i][j]+"	");
                    System.out.println();
                }
            }
            else
                System.out.println("查询失败");
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }
}