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;
     }

 }

连接数据库

 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();
         }

     }
 }

数据层封装

 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;
     }

 }

数据集封装

 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]+"\t");
                     System.out.println();
                 }
             }
             else
                 System.out.println("查询失败");
         } catch (SQLException e) {
             e.printStackTrace();
         }
     }
 }

测试Demo