1.pojo类

public class Category implements Serializable{		private String cid;   //分类主键	private String cname;   //分类名	private Category parent;  //父分类，是根据pid的自连接对象，一个二级分类只有一个一级分类	private String desc;   //描述	private List
    
      children;  //子分类，一个一级分类可能有多个二级分类，而二级分类无子分类		//setter and getter method...}
    

2.dao接口

public interface CategoryDao {			public Category load(String cid) throws SQLException;		public List
    
      findByParent(String pid) throws SQLException;		public List
     
       findParent() throws SQLException;	public void add(Category category) throws SQLException;		public void edit(Category category) throws SQLException;		public int findChildrenByParent(String pid) throws SQLException;		public void delete(String cid) throws SQLException;}
     
    

3.Mapper映射文件(切记实体类里的toString方法里边去掉类型为List的属性，要不然打印时会出现死循环的)。

    
    
      
        
         
         
         
         
         	
          
         
        
         
       	select *  	from   		t_category   	where   		cid=#{cid}        
       	select *  	from   		t_category   	where   		pid=#{cid}   	order by  		orderBy      
       	select *   		from t_category   		where pid is null   		order by orderBy