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丸趣 TV 小编给大家分享一下 java 连接 mysql 底层封装的示例分析，相信大部分人都还不怎么了解，因此分享这篇文章给大家参考一下，希望大家阅读完这篇文章后大有收获，下面让我们一起去了解一下吧！
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();
}
}
}以上是“java 连接 mysql 底层封装的示例分析”这篇文章的所有内容，感谢各位的阅读！相信大家都有了一定的了解，希望分享的内容对大家有所帮助，如果还想学习更多知识，欢迎关注丸趣 TV 行业资讯频道！
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