1.
import java.sql.DriverManager;
import java.sql.Connection;
import java.sql.Statement;
import java.sql.ResultSet;
import java.sql.SQLException;

public class JDBCExample
{
public static void main(String orgs[])
{
try
{
Class.forName("com.mysql.jdbc.Driver");//加载数据库驱动
String url="jdbc:mysql://localhost:3306/databasename";//数据库连接子协议
Connection conn=DriverManager.getConnection(url,"username","password");
Statement stmt=conn.createStatement();
ResultSet rs=stmt.executeQuery("select * from tablename");
while(rs.next())
{//不断指向下一条记录
System.out.println("DeptNo:"+rs.getInt(1));
System.out.println("\tDeptName:"+rs.getString(2));
System.out.println("\tLOC:"+rs.getString(3));
}
rs.close();
stmt.close();
conn.close();
}catch(ClassNotFoundException e)
{
System.out.println("找不到指定的驱动程序类!");
}catch(SQLException e)
{
e.printStackTrace();
}
}
}
2.
import java.sql.DriverManager;
import java.sql.Connection;
import java.sql.Statement;
import java.sql.ResultSet;
import java.sql.SQLException;

public class JDBCExample2
{
public static void main(String orgs[])
{
try
{
System.setProperty("jdbc.driver","com.mysql.jdbc.Driver");//系统属性指定数据库驱动
String url="jdbc:mysql://localhost:3306/databasename";//数据库连接子协议
Connection conn=DriverManager.getConnection(url,"username","password");
Statement stmt=conn.createStatement();
ResultSet rs=stmt.executeQuery("select * from tablename");
while(rs.next())
{//不断指向下一条记录
System.out.println("DeptNo:"+rs.getInt(1));
System.out.println("\tDeptName:"+rs.getString(2));
System.out.println("\tLOC:"+rs.getString(3));
}
rs.close();
stmt.close();
conn.close();
}catch(SQLException e)
{
e.printStackTrace();
}
}
}
3.
import java.sql.DriverManager;
import java.sql.Connection;
import java.sql.Statement;
import java.sql.ResultSet;
import java.sql.SQLException;

public class JDBCExample3
{
public static void main(String orgs[])
{
try
{
new com.mysql.jdbc.Driver();//创建driver对象,加载数据库驱动
String url="jdbc:mysql://localhost:3306/databasename";//数据库连接子协议
Connection conn=DriverManager.getConnection(url,"username","password");
Statement stmt=conn.createStatement();
ResultSet rs=stmt.executeQuery("select * from tablename");
while(rs.next())
{//不断指向下一条记录
System.out.println("DeptNo:"+rs.getInt(1));
System.out.println("\tDeptName:"+rs.getString(2));
System.out.println("\tLOC:"+rs.getString(3));
}
rs.close();
stmt.close();
conn.close();
}catch(SQLException e)
{
e.printStackTrace();
}
}
}
本文提供了Java JDBC数据库连接、驱动加载、查询数据的基本示例,包括使用Class.forName()、System.setProperty()和直接创建Driver对象的方法。通过实例演示了如何从数据库中获取数据并进行打印。
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