2. Connection con=DriverManager.getConnection("jdbc:mysql://localhost:3306/test","root","jb123456");
3. Statement st=con.createStatement();
2. String url="jdbc:mysql://localhost:3306/test";
3. String user="root";
4. String psw="jb123456";
5. Connection con=DriverManager.getConnection(url,user,psw);
使用返回的 Statement 对象创建的结果集在默认情况下类型为 TYPE_FORWARD_ONLY,并带有 CONCUR_READ_ONLY 并发级别。已创建结果集的可保存性可调用 getHoldability() 确定。
为什么说很自然呢,因为无论是网上还是书本教程上得例子都是这样的,而且程序也确实正常运行了,于是大家也就心安理得的找葫芦画瓢下去了。
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com.mysql.jdbc.Driver driver = new com.mysql.jdbc.Driver();
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//or:
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//new com.mysql.jdbc.Driver();
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String url = "jdbc:mysql://127.0.0.1/test?useUnicode=true&characterEncoding=utf-8";
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String user = "";
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String psw = "";
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Connection con = DriverManager.getConnection(url,user,psw);
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com.mysql.jdbc.Driver driver = null;
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//or:
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ClassLoader cl = new ClassLoader();
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cl.loadClass("com.mysql.jdbc.Driver");
哦,原来是com.mysql.jdbc.Driver在装载完后自动帮我们完成了这一步骤。源代码是这样的:
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package com.mysql.jdbc
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public class Driver extends NonRegisteringDriver implements java.sql.Driver
{
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// ~ Static fields/initializers
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// --------------------------------------------- //
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// Register ourselves with the DriverManager
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//
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static {
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t ry { -
java.sql.DriverManager.registerDriver(new Driver()); -
} catch (SQLException E) { -
throw new RuntimeException("Can't register driver!"); -
} -
} -
// ~ Constructors
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// -----------------------------------------------------------
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public Driver() throws SQLException
{
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// Required for Class.forName().newInstance() -
}
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}