mysql:
1、比较常用
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、通过系统的属性设置
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、看起来比较直观的一种方式，注册相应的db的jdbc驱动，3在编译时需要导入对应的lib
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();
}
oracel:
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
public class TestOracle {
public static void main(String[] args) {
Connection conn = null;
Statement stmt = null;
ResultSet rs = null;
try {
Class.forName("oracle.jdbc.driver.OracleDriver");//实例化oracle数据库驱动程序(建立中间件)
String url = "jdbc:oracle:thin:@localhost:1521:oar92";//@localhost为服务器名，sjzwish为数据库实例名
conn = DriverManager.getConnection(url, "guchao", "jimmy");//连接数据库，a代表帐户,a代表密码
stmt = conn.createStatement();//提交sql语句,创建一个Statement对象来将SQL语句发送到数据库
//查询数据用executeQuery
rs = stmt.executeQuery("select * from ruby");//执行查询,(ruby)为表名
while (rs.next()) {//使当前记录指针定位到记录集的第一条记录
System.out.println(rs.getString("sid") +" "+ rs.getString("sname"));
}//1代表当前记录的第一个字段的值，可以写成字段名。
//2代表当前记录的第二个字段的值，可以写成字段名。
//添加数据用executeUpdate
//stmt.executeUpdate("insert into ss values(7,'张学友')");
//修改数据用executeUpdate
//stmt.executeUpdate("update ss set name = '张曼玉' where id = 5");
//删除 数据用executeUpdate
//stmt.executeUpdate("delete from ss where id = 6");
} catch (SQLException e) {
e.printStackTrace();
} catch (ClassNotFoundException e) {
e.printStackTrace();
}finally{
try {
//关闭数据库，结束进程
rs.close();
stmt.close();
conn.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
}
}
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