jdbc连接数据库的代码问题jdbc连接mysql数据库

用这个类吧.好的话,给我加加分.

import java.sql.*

/**

* @功能: 一个JDBC的本地化API连接类,封装了数据 *** 作方法,只用传一个SQL语句即可

* @作者: 李开欢

* @日期: 2007/

*/

public class ConnectionDemo {

/*

* 这里可以将常量全部放入另一个类中,以方便修改

*/

private static Connection conn

private static Statement ps

private static ResultSet rs

private static final String DRIVER = "com.microsoft.jdbc.sqlserver.SQLServerDriver"

private static final String URL = "jdbc:microsoft:sqlserver://localhost:1433DatabaseName=mydb"

private static final String USER ="sa"

private static final String PASS = "sa"

public ConnectionDemo() {

// TODO Auto-generated constructor stub

ConnectionDemo.getConnection()

}

public static Connection getConnection(){

System.out.println("连接中...")

try {

Class.forName(ConnectionDemo.DRIVER)

conn = DriverManager.getConnection(ConnectionDemo.URL, ConnectionDemo.USER, ConnectionDemo.PASS)

System.out.println("成功连接")

} catch (ClassNotFoundException e) {

// TODO Auto-generated catch block

e.printStackTrace()

} catch (SQLException e) {

// TODO Auto-generated catch block

e.printStackTrace()

}

return conn

}

public static Statement getStatement(String sql){

System.out.println("执行SQL语句中...")

try {

ps = conn.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE, ResultSet.CONCUR_UPDATABLE)

if(sql.substring(0, 6).equals("select")){

rs = ps.executeQuery(sql)

System.out.println("执行完查询 *** 作,结果已返回ResultSet集合")

}else if(sql.substring(0, 6).equals("delete")){

ps.executeUpdate(sql)

System.out.println("已执行完毕删除 *** 作")

}else if(sql.substring(0, 6).equals("insert")){

ps.executeUpdate(sql)

System.out.println("已执行完毕增加 *** 作")

}else{

ps.executeUpdate(sql)

System.out.println("已执行完毕更新 *** 作")

}

} catch (SQLException e) {

// TODO Auto-generated catch block

e.printStackTrace()

}

return ps

}

public static ResultSet getResultSet(){

System.out.println("查询结果为:")

return rs

}

public static void closeConnection(){

System.out.println("关闭连接中...")

try {

if (rs != null) {

rs.close()

System.out.println("已关闭ResultSet")

}

if (ps != null) {

ps.close()

System.out.println("已关闭Statement")

}

if (conn != null) {

conn.close()

System.out.println("已关闭Connection")

}

} catch (Exception e) {

// TODO: handle exception

}

}

public static void main(String[] args) {

// TODO Auto-generated method stub

ConnectionDemo.getConnection()

String sql = "delete from type where id = 1"

ConnectionDemo.getStatement(sql)

String sql2 = "insert into type values(1,'教学设备')"

ConnectionDemo.getStatement(sql2)

String sql1 = "select * from type"

ConnectionDemo.getStatement(sql1)

ResultSet rs = ConnectionDemo.getResultSet()

System.out.println("编号 "+"类型")

try {

while(rs.next()){

System.out.print(" "+rs.getInt(1)+" ")

System.out.println(rs.getString(2))

}

} catch (SQLException e) {

// TODO Auto-generated catch block

e.printStackTrace()

}

ConnectionDemo.closeConnection()

}

}

当我用JDBC连接MySql数据库时，编译报了如下错误：

错误1：

Loading class `com.mysql.jdbc.Driver'. This is deprecated. The new driver class is `com.mysql.cj.jdbc.Driver'. The driver is automatically registered via the SPI and manual loading of the driver class is generally unnecessary.

这要求我们注册驱动时，把Class.forName("com.mysql.jdbc.Driver")改成 Class.forName("com.mysql.cj.jdbc.Driver")

当我信息满满的修改之后重新编译时，再次出现了错误：

错误2：

Fri Feb 22 08:55:38 CST 2019 WARN: Establishing SSL connection without server's identity verification is not recommended. According to MySQL 5.5.45+, 5.6.26+ and 5.7.6+ requirements SSL connection must be established by default if explicit option isn't set. For compliance with existing applications not using SSL the verifyServerCertificate property is set to 'false'. You need either to explicitly disable SSL by setting useSSL=false, or set useSSL=true and provide truststore for server certificate verification.

这要求我们在设置url参数时，将useSSL=false，修改后 jdbc:mysql://localhost:3306/ds3?useSSL=false

当我修改后，本以为这下应该没问题了，没想到，再一次出现了问题

错误3：

Exception in thread "main" java.sql.SQLException: The server time zone value 'Öйú±ê׼ʱ¼ä' is unrecognized or represents more than one time zone. You must configure either the server or JDBC driver (via the serverTimezone configuration property) to use a more specifc time zone value if you want to utilize time zone support.

这要求我们修改时区，修改成jdbc:mysql://localhost:3306/ds3?useSSL=false&serverTimezone=UTC

终于，不在报错误了。

错误4：当我们配置xml文件时，要把&转为其本身的转义字符

配置properties文件的urlurl=jdbc:mysql:///ds3?useSSL=false&serverTimezone=UTC配置xml文件的url<property name="url">jdbc:mysql://localhost:3306/ds3?useSSL=false&serverTimezone=UTC</property>

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