java如何连接mysql底层封装

这篇文章主要介绍java如何连接mysql底层封装，文中介绍的非常详细，具有一定的参考价值，感兴趣的小伙伴们一定要看完！

具体内容如下

连接数据库

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

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

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

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();    }  }}

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