Java学习笔记（六）数据的操作(增、删、改的操作)

 jdbc操作数据库的步骤：
 加载驱动->获得数据库连接->创建操作数据库的连接对象->写sql语句->执行sql语句。

//testODBC.OdbcTest.java
//
package testODBC;

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

public class OdbcTest {
    static Connection conn = null;
    static Statement stm = null;
    public static void main(String[] args) {
        //不带参数的sql语句 ，删除语句
        //String str = "delete emp where empno = 7456";
        
        //带参数的sql语句
        String strname = "d国的";
        int empno = 7456;
        //单引号的问题，字符注意带单引号。。更新语句
        //String str = "update emp set ename = '" + strname + "' where empno = " + "'" + empno + "'";
        //插入语句
        String str = "insert into emp(empno,ename) values ('"+empno + "','" + strname+"')";
        addDelModify(str);
    }
    private static void addDelModify(String str) {
        try {
            Class.forName( "oracle.jdbc.driver.OracleDriver");// 加载驱动
            String url = "jdbc:oracle:thin:@localhost:1521:ORCL";// 访问oracle路径
            conn = DriverManager.getConnection(url, "scott", "tiger");//获得数据库连接
            stm = conn.createStatement();
            //执行sql语句并返回布尔值，返回false，表示执行成功。否则执行失败
            /*boolean bool = stm.execute(str);
            System.out.println(bool);*/
            //执行sql语句返回整数值，表示改变的行数
            int lines = stm.executeUpdate(str);
            System.out.println(lines);
        } catch (ClassNotFoundException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (SQLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }finally{
            try {
                //关闭statement
                stm.close();
                //关闭数据库连接
                if (conn.isClosed()) {
                    System.out.println("连接已经关闭！");
                } else {
                    conn.close();
                    System.out.println("执行关闭连接！");
                }
            } catch (SQLException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
            
        }
    }
}