java连接mysql底层封装详解

本文实例为大家分享了java连接mysql底层封装代码，供大家参考，具体内容如下

连接数据库

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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 ;   }   }

数据层封装

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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();    }      } }

数据集封装

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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;   }       }

测试Demo

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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();    }   } }

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持服务器之家。

原文链接：https://www.cnblogs.com/FCWORLD/p/3401622.html