请教关于ORACLE调用java类的返回数据类型


--创建用户表
create table users (
    uid varchar2(10) not null primary key,
    userName varchar2(20) not null,
    pwd varchar2(20) not null
);
--创建序列
create or replace sequence seq
start with 1 
increment by 1
maxvalue 20
minvalue 20
cycle
cache 20;
--创建一个有返回 procedure 首先需要创建一个包
create or replace package pk_userlist
as
type ref_users is ref cursor; --声明动态游标
end pk_userlist;
create or replace procedure sel_userlist(u_cursor out pk_userlist.ref_users)
is
begin
open u_cursor for select * from users;
end sel_userlist;下面是 java调用代码/建立一个持久类
public class Users implement java.io.Serializable {
            private Integer uid;
            private String userName;
            private String pwd;            public Users(){
            }
            public Users(Integer uid){
                    this.uid = uid;
            }
            public Users(Integer uid,String userName,String pwd){
                   this.uid = uid;
                   this.userName = userName;
                   this.pwd = pwd;
            }
            public void setUid(Integer uid){
                    this.uid = uid;
            }
            public Integer getUid(){
                    return uid;
            }
            public void setUserName(String userName){
                   this.userName = userName;
            }
            public String getUserName(){
                   return userName;
            }
            public void setPwd(String pwd){
                  this.pwd = pwd;
            }
            public String getPwd(){
                  return pwd;
            }
}//end class Users
//连接数据库类
public class ConManager {
           private static String driver = "oracle.jdbc.driver.OracleDriver";
           private static String url = "jdbc:oracle:thin:@localhost:1521:orcl";
           private static String userName = "scott";
           private static String pwd = "tiger";
                //加载 oracle 驱动
               static {
                      try{
                  Class.forName(driver);
     }catch(ClassNotFoundException ex){
               ex.printStackTrace();
     }catch(Exception ex){
               ex.printStackTrace();
     }
                }
                //获取连接
                public static Connection getConnection() {
                       try{
                return DriverManager.getConnection(url,userName,pwd);
        }catch(SQLException ex){
                ex.printStackTrace();
                return null;
                         }catch(Exception ex){
                ex.printStackTrace();
                return null;
                        }
              }//end getConnection()
}// end class ConManagerpublic class UserDaoImpl{
            private Connection conn = null;
            private CallableStatement proc = null;
            private ResultSet rs = null;
            private Users users = null;            //查询方法，返回列表
            public List getUserAll(){
            List result = new ArrayList();
            try{
    conn = ConManager.getConnection();
    //如果得到的 connection 为空,直接返回一个 null;
    if(conn == null){
             return null;
    }
    /*调用存储过程*/
    proc = conn.prepareCall("{ call scott.sel_userlist(?)}");
    /*传入一个输出参数,因为前面定义的存储过程参数是包,包里定义了一个游标,所以这里传进来一个游标用来输出*/
    proc.registerOutParameter(1,oracle.jdbc.OracleTypes);
    /*执行存储过程*/
    proc.execute();
    /*得到结果集,并转换为 ResultSet */
    rs = (ResultSet)proc.getObject(1);
    while(rs.next()){
                            users = new Users();
                            users.setUid(rs.getInt("uid"));
           users.setUserName(rs.getString("userName"));
           users.setPwd(rs.getString("pwd"));
           result.add(users);
    }
    /*
                       *这里判断并不是必须,可在前台处理,前台我这就不写了,这里这样写只是为了更好的理解,
                       *真正开发最好放在前台处理
     *前台写法与这里一样,如果是结合struts or servlet 写法如下:
     *List list = UserDaoImpl.getUserAll();
     *if(list == null){
     *   request.setAttribute("error","没有你要查询的数据!!!"); 
     *}
    */
    if(result.size() > 0 && result != null){
           return result;
    }
    else{
           throw new Exception("没有你要查询的数据!!!");
    }
           }catch(SQLException ex){
    ex.printStackTrace();
           }catch(Exception ex){
      ex.printStackTrace();
           }finally{
              try{
    //释放所有资源,关闭连接
    users = null;
    this.close(rs,proc,null,conn);
             }catch(SQLException ex){
    ex.printStackTrace();
             }
            }
             return null;
} //end getUserAll()
//关闭连接
public void close(ResultSet rs,CallableStatement proc,PreparedStatement ps,Connection conn){
            if(rs != null){
                  try{
    rs.close();
                  }catch(SQLException ex){
    ex.printStackTrace();
                  }
            }
            if(proc != null){
                  try{
    proc.close();
                  }catch(SQLException ex){
    ex.printStackTrace();
                  }
           }
           if(ps != null){
                  try{
    ps.close();
                  }catch(SQLException ex){
    ex.printStackTrace();
                  }
           }
           if(conn != null){
                  try{
    conn.close();
                   }catch(SQLException ex){
    ex.printStackTrace();
                   }
           }
   }//end close();
}//end class UserDaoImpl