javabean的封装

Question

db 类package insertbean;import java.net.*;
import java.sql.*;
import java.io.*;class db{
    Connection conn;
    Statement stmt;    public void getConnection(){
        try{
            String driv = "oracle.jdbc.driver.OracleDriver";
            Class.forName(driv);
            String url = "jdbc:oracle:thin:@localhost:1521:peter";
            conn = DriverManager.getConnection(url,"scott","tiger");
            System.out.println("已连接到数据库！");
        }
        catch(Exception e){
            System.out.println("出现异常" + e.getMessage());
        }
    }
    public void closeConnection(){
        try{
            if(conn!=null){
                conn.close();
            }
        }
        catch(Exception e){
            System.out.println(e.getMessage());
        }
    }
    public boolean executeUpdate(String sql){
        try{
            getConnection();
            if(conn != null){
                stmt = conn.createStatement();
                stmt.executeUpdate(sql);
            }
            return true;
        }
        catch(Exception e){
            System.out.println(e.getMessage());
            return false;
        }
    }
}
emp类package insertbean;import java.sql.*;class emp extends db{
    private String empno;
    private String ename;
    public boolean update(){
         String sSql = new String("insert into emp(empno,ename)");
         sSql = sSql + "values('"+ empno +"','"+ ename + "')";
         boolean ret = executeUpdate(sSql);
         return ret;
    }
    public void setename(String en){
        ename = en;
    }
    public void setempno(String em){
        empno = em;
    }
}testbean类package insertbean;import java.io.*;
import java.sql.*;class testbean{
    public static void main(String args[]){
        String empno;
        String ename;
        emp em;        try{
            System.out.println("请输入工号：");
            BufferedReader br= new BufferedReader(new InputStreamReader(System.in));
            empno=br.readLine();
            System.out.println("请输入姓名：");
            br= new BufferedReader(new InputStreamReader(System.in));
            ename=br.readLine();            em= new emp();
            em.setempno(empno);
            em.setename(ename);            boolean ret = em.update();
            if(ret){
                System.out.println("新增记录成功！");
            }
            else{
                System.out.println("新增记录失败！");
            }
            em.closeConnection();
        }
        catch(Exception e){
            System.out.println(e.getMessage());
        }
    }
}
运行后
出现异常oracle.jdbc.driver.OracleDriver
新增记录成功！为什么这个插在数据库里没有结果呢
最后显示插入成功

Answer 1

getConnection()方法应该抛出异常，
这样executeUpdate（）中才能捕捉到。
public void getConnection() throws Exception {
        try{
            String driv = "oracle.jdbc.driver.OracleDriver";
            Class.forName(driv);
            String url = "jdbc:oracle:thin:@localhost:1521:peter";
            conn = DriverManager.getConnection(url,"scott","tiger");
            System.out.println("已连接到数据库！");
        }
        catch(Exception e){
            System.out.println("出现异常" + e.getMessage());
            throw new Exception(("出现异常" + e.getMessage())
        }
    }

Answer 2

throw new Exception(("出现异常" + e.getMessage())是什么意思呢
getConnection()方法已经抛出异常了呀

Answer 3

throw new Exception(("出现异常" + e.getMessage())
况且这句加在这会报错呀