java 连接mysql底层封装详解

本文为大家分享了java连接mysql底层封装代码，供大家参考。

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();
}
}
}

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编程宝库。

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