装饰器模式下的JDBC连接数据库
实现JDBC连接数据库的接口,再重写MySQL、SQLServer、Oracle的数据库。
构建数据库连接的四元素driver,url,user,password
不同的数据库对driver、url的定义是不同的。
在对JBDC连接模式需要先导入jar包。

Oracle的driver和url的定义
// An highlighted block
private static final String driver="oracle.jdbc.driver.OracleDriver";
private static final String url="jdbc:oracle:thin:@127.0.0.1:1521:orcl";
MySQL的driver和url的定义。
// An highlighted blockprivate static final String driver="com.microsoft.sqlserver.jdbc.SQLServerDriver";//the driver
private static final String url="jdbc:sqlserver://localhost:8080; DatabaseName=sample";//url
private static final String driver="com.mysql.jdbcDriver";//驱动
private static final String url="";//url
SQLserver的driver和url的定义
代码
Oracle数据库的JDBC模式。
// An highlighted block
package com;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.sql.Statement;
//接口的实体应用对应特殊的数据库
public class Oracle implements demo{
private static final String driver="oracle.jdbc.driver.OracleDriver";//the driver
private static final String url="jdbc:oracle:thin:@127.0.0.1:1521:orcl";//url
private static final String user="root";//the database user
private static final String password="123";//the database password
public void insert()
{
String sql="INSERT into tb1(id, name) VALUES(1,'zhangsan');";
Connection connection = null;
Statement statement = null;
try {
//loading driver
Class.forName(driver);
//deprive the datebase connecting object
connection = DriverManager.getConnection(url, user, password);
//deprive the object
statement = connection.createStatement();
//使用这个对象来执行SQL
int i = statement.executeUpdate(sql);
System.out.println("插入完毕"+i+"条");
} catch (Exception e) {
e.printStackTrace();
}finally {
try {
if(statement != null){
statement.close();
}
if(connection != null){
connection.close();
}
} catch (SQLException e) {
e.printStackTrace();
}
}
}
public void update()
{
String sql="update tb1 t set t.id='2',t.name='lisi';";
Connection connection = null;
Statement statement = null;
try {
//loading driver
Class.forName(driver);
//deprive the datebase connecting object
connection = DriverManager.getConnection(url, user, password);
//deprive the object
statement = connection.createStatement();
//使用这个对象来执行SQL
int i = statement.executeUpdate(sql);
System.out.println("修改完毕"+i+"条");
} catch (Exception e) {
e.printStackTrace();
}finally {
try {
if(statement != null){
statement.close();
}
if(connection != null){
connection.close();
}
} catch (SQLException e) {
e.printStackTrace();
}
}
}
@Override
public void delete()
{
String sql="delete from tb1 where tb1_id=1;";
Connection connection = null;
Statement statement = null;
try {
//loading driver
Class.forName(driver);
//deprive the datebase connecting object
connection = DriverManager.getConnection(url, user, password);
//deprive the object
statement = connection.createStatement();
//使用这个对象来执行SQL
int i = statement.executeUpdate(sql);
System.out.println("删除完毕"+i+"条");
} catch (Exception e) {
e.printStackTrace();
}finally {
try {
if(statement != null){
statement.close();
}
if(connection != null){
connection.close();
}
} catch (SQLException e) {
e.printStackTrace();
}
}
}
@Override
public void select()
{
String sql=" select * from tb1;";
Connection connection = null;
Statement statement = null;
try {
//loading driver
Class.forName(driver);
//deprive the datebase connecting object
connection = DriverManager.getConnection(url, user, password);
//deprive the object
statement = connection.createStatement();
//使用这个对象来执行SQL
int i = statement.executeUpdate(sql);
System.out.println("删除完毕"+i+"条");
} catch (Exception e) {
e.printStackTrace();
}finally {
try {
if(statement != null){
statement.close();
}
if(connection != null){
connection.close();
}
} catch (SQLException e) {
e.printStackTrace();
}
}
}
}
MySQL数据库的JDBC连接
package com;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.sql.Statement;
public class mysql implements demo{
//
private static final String driver="com.mysql.jdbcDriver";//驱动
private static final String url="";//url
private static final String user="root";//数据库中的用户名字
private static final String password="123";//数据库中的密码
public void insert()
{ //perparing the Sql language
String sql="insert into tb1(id, name) VALUES(1,'zhangsan');";
//initailize the object
Connection connection = null;
Statement statement = null;
try {
//loading driver
Class.forName(driver);
//getting the datebase connecting object
connection = DriverManager.getConnection(url, user, password);
//get the accessible sql object
statement = connection.createStatement();
//used the object to access the sql
int i = statement.executeUpdate(sql);
System.out.println("插入完毕"+i+"条");
} catch (Exception e) {
e.printStackTrace();
}finally {
try {
if(statement != null){
statement.close();
}
if(connection != null){
connection.close();
}
} catch (SQLException e) {
e.printStackTrace();
}
}
}
public void update()
{
String sql="update tb1 t set t.id='2',t.name='lisi';";
Connection connection = null;
Statement statement = null;
try {
//loading driver
Class.forName(driver);
//getting the datebase connecting object
connection = DriverManager.getConnection(url, user, password);
//get the accessible sql object
statement = connection.createStatement();
//used the object to access the sql
int i = statement.executeUpdate(sql);
System.out.println("修改完毕"+i+"条");
} catch (Exception e) {
e.printStackTrace();
}finally {
try {
if(statement != null){
statement.close();
}
if(connection != null){
connection.close();
}
} catch (SQLException e) {
e.printStackTrace();
}
}
}
@Override
public void delete()
{
String sql="delete from tb1 where tb1_id=1;";
Connection connection = null;
Statement statement = null;
try {
//loading driver
Class.forName(driver);
//getting the datebase connecting object
connection = DriverManager.getConnection(url, user, password);
//get the accessible sql object
statement = connection.createStatement();
//used the object to access the sql
int i = statement.executeUpdate(sql);
System.out.println("删除完毕"+i+"条");
} catch (Exception e) {
e.printStackTrace();
}finally {
try {
if(statement != null){
statement.close();
}
if(connection != null){
connection.close();
}
} catch (SQLException e) {
e.printStackTrace();
}
}
}
@Override
public void select()
{
String sql=" select * from tb1;";
Connection connection = null;
Statement statement = null;
try {
//loading driver
Class.forName(driver);
//getting the datebase connecting object
connection = DriverManager.getConnection(url, user, password);
//get the accessible sql object
statement = connection.createStatement();
//used the object to access the sql
int i = statement.executeUpdate(sql);
System.out.println("删除完毕"+i+"条");
} catch (Exception e) {
e.printStackTrace();
}finally {
try {
if(statement != null){
statement.close();
}
if(connection != null){
connection.close();
}
} catch (SQLException e) {
e.printStackTrace();
}
}
}
}
Oracle数据库的JDBC模式连接代码.
package com;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.sql.Statement;
//接口的实体应用对应特殊的数据库
public class Oracle implements demo{
private static final String driver="oracle.jdbc.driver.OracleDriver";//the driver
private static final String url="jdbc:oracle:thin:@127.0.0.1:1521:orcl";//url
private static final String user="root";//the database user
private static final String password="123";//the database password
public void insert()
{
String sql="INSERT into tb1(id, name) VALUES(1,'zhangsan');";
Connection connection = null;
Statement statement = null;
try {
//loading driver
Class.forName(driver);
//deprive the datebase connecting object
connection = DriverManager.getConnection(url, user, password);
//deprive the object
statement = connection.createStatement();
//使用这个对象来执行SQL
int i = statement.executeUpdate(sql);
System.out.println("插入完毕"+i+"条");
} catch (Exception e) {
e.printStackTrace();
}finally {
try {
if(statement != null){
statement.close();
}
if(connection != null){
connection.close();
}
} catch (SQLException e) {
e.printStackTrace();
}
}
}
public void update()
{
String sql="update tb1 t set t.id='2',t.name='lisi';";
Connection connection = null;
Statement statement = null;
try {
//loading driver
Class.forName(driver);
//deprive the datebase connecting object
connection = DriverManager.getConnection(url, user, password);
//deprive the object
statement = connection.createStatement();
//使用这个对象来执行SQL
int i = statement.executeUpdate(sql);
System.out.println("修改完毕"+i+"条");
} catch (Exception e) {
e.printStackTrace();
}finally {
try {
if(statement != null){
statement.close();
}
if(connection != null){
connection.close();
}
} catch (SQLException e) {
e.printStackTrace();
}
}
}
@Override
public void delete()
{
String sql="delete from tb1 where tb1_id=1;";
Connection connection = null;
Statement statement = null;
try {
//loading driver
Class.forName(driver);
//deprive the datebase connecting object
connection = DriverManager.getConnection(url, user, password);
//deprive the object
statement = connection.createStatement();
//使用这个对象来执行SQL
int i = statement.executeUpdate(sql);
System.out.println("删除完毕"+i+"条");
} catch (Exception e) {
e.printStackTrace();
}finally {
try {
if(statement != null){
statement.close();
}
if(connection != null){
connection.close();
}
} catch (SQLException e) {
e.printStackTrace();
}
}
}
@Override
public void select()
{
String sql=" select * from tb1;";
Connection connection = null;
Statement statement = null;
try {
//loading driver
Class.forName(driver);
//deprive the datebase connecting object
connection = DriverManager.getConnection(url, user, password);
//deprive the object
statement = connection.createStatement();
//使用这个对象来执行SQL
int i = statement.executeUpdate(sql);
System.out.println("删除完毕"+i+"条");
} catch (Exception e) {
e.printStackTrace();
}finally {
try {
if(statement != null){
statement.close();
}
if(connection != null){
connection.close();
}
} catch (SQLException e) {
e.printStackTrace();
}
}
}
}
生成一个适合你的列表
- 项目
- 项目
- 项目
- 项目
- 项目1
- 项目2
- 项目3
- 计划任务
- 完成任务
创建一个表格
一个简单的表格是这么创建的:
| 项目 | Value |
|---|---|
| 电脑 | $1600 |
| 手机 | $12 |
| 导管 | $1 |
设定内容居中、居左、居右
使用:---------:居中
使用:----------居左
使用----------:居右
| 第一列 | 第二列 | 第三列 |
|---|---|---|
| 第一列文本居中 | 第二列文本居右 | 第三列文本居左 |
SmartyPants
SmartyPants将ASCII标点字符转换为“智能”印刷标点HTML实体。例如:
| TYPE | ASCII | HTML |
|---|---|---|
| Single backticks | 'Isn't this fun?' | ‘Isn’t this fun?’ |
| Quotes | "Isn't this fun?" | “Isn’t this fun?” |
| Dashes | -- is en-dash, --- is em-dash | – is en-dash, — is em-dash |
创建一个自定义列表
-
Markdown
- Text-to- HTML conversion tool Authors
- John
- Luke
如何创建一个注脚
一个具有注脚的文本。1
注释也是必不可少的
Markdown将文本转换为 HTML。
KaTeX数学公式
您可以使用渲染LaTeX数学表达式 KaTeX:
Gamma公式展示 Γ ( n ) = ( n − 1 ) ! ∀ n ∈ N \Gamma(n) = (n-1)!\quad\forall n\in\mathbb N Γ(n)=(n−1)!∀n∈N 是通过欧拉积分
Γ ( z ) = ∫ 0 ∞ t z − 1 e − t d t . \Gamma(z) = \int_0^\infty t^{z-1}e^{-t}dt\,. Γ(z)=∫0∞tz−1e−tdt.
你可以找到更多关于的信息 LaTeX 数学表达式here.
新的甘特图功能,丰富你的文章
- 关于 甘特图 语法,参考 这儿,
UML 图表
可以使用UML图表进行渲染。 Mermaid. 例如下面产生的一个序列图:
这将产生一个流程图。:
- 关于 Mermaid 语法,参考 这儿,
FLowchart流程图
我们依旧会支持flowchart的流程图:
- 关于 Flowchart流程图 语法,参考 [这儿][4].
导出与导入
导出
如果你想尝试使用此编辑器, 你可以在此篇文章任意编辑。当你完成了一篇文章的写作, 在上方工具栏找到 文章导出 ,生成一个.md文件或者.html文件进行本地保存。
导入
如果你想加载一篇你写过的.md文件,在上方工具栏可以选择导入功能进行对应扩展名的文件导入,
继续你的创作。
[4]: http://adrai.github.io/flowchart.js/## 标题
注脚的解释 ↩︎
本文详细展示了如何使用装饰器模式在Java中分别连接Oracle和MySQL数据库,通过自定义接口并实现不同数据库的驱动和URL。包括数据库连接的驱动类和URL定义,以及插入、更新、删除和查询操作的实现。
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