查询Departments表中所有的信息(JDBC方法)--笔记

public static List getAllDepartment(){
    (1)创建List类的对象list，用来实现其Add方法
    List list = new Arraylist();
    (2)调用构建好的SQL和JAVA运行环境，并创建ResultSet类的对象rs来存储缓存表格   
    Connection con=DMmanager.getConnection();
    PreparedStatement pst= null;
    String str = "select * from department";
    ResultSet rs =null;
    pst = con.PrepareStatement(str);
    rs = pst.executeQuery();
    (3)利用一个while 将rs缓存表中的每一列Columns属性/ 通过 Department类对象dep的方法获取table中Columns的属性   
     while(rs.hasNext()){
        Department dep = new Department();

        dep.setId(rs.getInt("department_id"));
        dep.setName(rs.getString("department_name"));
        dep.setSalary(rs.getFlaot("salary"));
        dep.setLocation_id(rs.getInt("location_id"));
      (4) 将(3)的结果add到list中       
         list.add(dep);
     }
        rs.close();
        pst.close();
        con.close();
        return list;
}
    (5)构建一个输出方法
     public static void printAll(Department dep){
      System.out.println(dep.getId());
      System.out.println(dep.getName());
      System.out.println(dep.getSalary());
      System.out.println(dep.getLocation_id());
}
     (6)运行主函数
      public static void main(String[] args) {
     List list=getAllDepartment();
     iterator it =list.iterator();
       while(it.hasNext()){
          Department dep =new Department();
          printAll(dep);
}
}