廣告

2016年8月7日 星期日

[git]Untrack files from git

This will tell git you want to start ignoring the changes to the file
git update-index --assume-unchanged path/to/file

When you want to start keeping track again
git update-index --no-assume-unchanged path/to/file

usage occasion : put some file in remote once and not track it anymore

                 ex:local config

2016年7月13日 星期三

2016年6月23日 星期四

Hibernate Eager vs Lazy Fetch Type


  @OneToOne(fetch=FetchType.EAGER) //LAZY
  @JoinColumn(name="user_profile_id")
  private Profile getUserProfile()
  {
   return userProfile;
  }

 FetchType.LAZY = Doesn’t load the relationships 
 unless explicitly “asked for” via getter
 FetchType.EAGER = Loads ALL relationships

ref:
https://m.oschina.net/blog/327056
https://howtoprogramwithjava.com/hibernate-eager-vs-lazy-fetch-type/

2016年6月8日 星期三

Hibernate paging get error result if row have same value


Query queryHot = session.createQuery(
   "from HotPost ORDER BY popularity DESC");

queryHot.setFirstResult((page - 1) * pageSize);
queryHot.setMaxResults(pageSize);

solve:
Query queryHot = session.createQuery(
   "from HotPost ORDER BY popularity DESC,id");
==================================
Before:
id   popularity 
1     9   |
2     8   |  page 1
3     8   |

5     8   |
6     7   |  page 2
7     5   |

AFTER:
id   popularity 
1     9  |
2     8  |  page 1
3     8  |

4     8  |
5     7  |  page 2
6     5  |


2016年5月19日 星期四

Hibernate  one-to-one mapping cautions


正確用法
@OneToOne(mappedBy = "post")
@JsonView(View.Detail.class)
private HotPost hotPost;

一開始犯傻
@OneToOne(mappedBy = "post")
@JsonView(View.Detail.class)
Set hotpost = new HashSet<>(0);
CautionsCautionsCautions
log只會說:Unknown mappedBy in: com.ws.pojo.Post.hotPost, referenced property unknown: java.util.Set.post


but @OneToMany
remember to use Set


ref:




Hibernate batch process


 //in pojo (java bean)
      @BatchSize(size=5)
------------------------------------------------
      public void insertOldPost2HotPost() throws Exception{
       
       Session session = sessionFactory.getCurrentSession();

        @SuppressWarnings("unchecked")
        List posts = session.createQuery("from Post ").list();
        int itCount=0;
        for(Iterator it = posts.iterator(); it.hasNext(); ) {

            itCount++;

            Post post = (Post) it.next();

            HotPost hotPost = new HotPost(post);
            session.saveOrUpdate(hotPost);

            if (itCount % 5 == 0) {
            
                session.flush();
                session.clear();
            }
        }
    }


ref:


2016年5月10日 星期二

Spring MVC @JsonView使用详解


     public class View {
      interface Summary {}
      interface SummaryWithDetail extends Summary{}
    }
    -----------------------------------
    public class User {
      @JsonView(View.Summary.class)
      private Long id;
      @JsonView(View.SummaryWithDetail.class)
      private String firstname;
    }
    -----------------------------------
    @RequestMapping("/user")[
    @JsonView(View.Summary.class)
    //or @JsonView(View.SummaryWithDetail.class)
    public List getUsers(){
     return userService.listUsers();
    }
    -----------------------------------
    result of @JsonView(View.Summary.class)
    [
     {
        "id": 70,
     }
    ]

    result of @JsonView(View.SummaryWithDetail.class)
    [
     {
        "id": 70,
        "firstname": 222
     }
    ]