SSM + PageHelper, ssmpagehelper

SSM + PageHelper, ssmpagehelper

Maven is used in the project.

1 introduce the jar package

　　First, introduce the jar package of PageHelper.

If maven is used, you only need to introduce the plug-in pom. xml as follows:

　　<dependency>  

     <groupId>com.github.pagehelper</groupId>

     <artifactId>pagehelper</artifactId>

     <version>4.1.4</version>

</Dependency>
Be sure to note: the version number cannot be too low. When is used at the beginning, the error 500 is reported and the page is not correct.
2. Configure in sqlMapConfig. xml:

 

1. <! -- Configure the paging plug-in -->
2. <Plugins>
3. <Plugin interceptor = "com. github. pagehelper. PageHelper">
4. <! -- Set six database types: Oracle, Mysql, MariaDB, SQLite, Hsqldb, and PostgreSQL -->
5. <Property name = "dialect" value = "mysql"/>
6. <! -- This parameter defaults to false -->
7. <! -- If it is set to true, the first parameter offset of RowBounds is used as the pageNum page number. -->
8. <! -- The same effect as pageNum in startPage -->
9. <Property name = "offsetAsPageNum" value = "true"/>
10. <! -- This parameter defaults to false -->
11. <! -- If it is set to true, the RowBounds page will be used for count query -->
12. <Property name = "rowBoundsWithCount" value = "true"/>
13. <! -- 3.3.0 available-the paging parameter is rationalized. The default value is false. -->
14. <! -- When the rationalization is enabled, if pageNum <1, the first page is queried. If pageNum> pages, the last page is queried. -->
15. <! -- When the rationalization is disabled, if pageNum <1 or pageNum> pages returns NULL data -->
16. <Property name = "reasonable" value = "true"/>
17. <! -- Pagination parameters can be passed through Mapper interface parameters -->
18. <Property name = "supportMethodsArguments" value = "true"/>
19. <! -- Always returns the PageInfo type. check whether the returned type is PageInfo. If not, Page is returned. -->
20. <Property name = "returnPageInfo" value = "check"/>
21. </Plugin>
22. </Plugins>

3. The serviceImpl receives the results from mapper. xml and uses pagehelper for paging.
Example:

Public TbResult getArticleByType (String type, int pageNumber, int pageSize ){
TbArticleExample example = new TbArticleExample ();
Criteria criteria = example. createCriteria ();
Criteria. andtype0000to (type );
PageHelper. startPage (pageNumber, pageSize );
List <TbArticle> art = articleMapper. selectByExampleWithBLOBs (example );
PageInfo <TbArticle> pageInfo = new PageInfo <> (art );
TbResult result = new TbResult ();
Result. setRows (art );
Result. setTotal (pageInfo. getTotal ());
Return result;
}

We can see that PageHelper. startPage (pageNumber, pageSize); is displayed before executing the SQL statement. PageInfo is actually the result that has been divided. Here I will split the result into a TbResult class, later I found that this is not required. PageInfo. getList () is art, so you can directly return pageInfo.

4. You can receive the result at the Controller layer.