Pagehelper分页查询

系统管理员 2023-02-14 13:06 8阅读 0赞

## Mybatis的分页查询 ##

pagehelper：只适合小规模数据的分页操作  
依赖

<dependency>
       <groupId>com.github.pagehelper</groupId>
       <artifactId>pagehelper-spring-boot-starter</artifactId>
       <version>1.2.5</version>
    </dependency>
    
    
    <dependency>
       <groupId>com.alibaba</groupId>
       <artifactId>druid</artifactId>
       <version>1.1.10</version>
    </dependency>
    
    <dependency>
       <groupId>mysql</groupId>
       <artifactId>mysql-connector-java</artifactId>
    </dependency>
    
    <dependency>
       <groupId>org.mybatis.spring.boot</groupId>
       <artifactId>mybatis-spring-boot-starter</artifactId>
       <version>1.2.0</version>
    </dependency>

**application.properties**

#mysql
    spring.datasource.type=com.alibaba.druid.pool.DruidDataSource
    spring.datasource.driverClassName=com.mysql.jdbc.Driver
    spring.datasource.url=jdbc:mysql://127.0.0.1:3306/txdyl?useSSL=false&useUnicode=true&characterEncoding=utf-8&zeroDateTimeBehavior=convertToNull&autoReconnect=true&allowMultiQueries=true&serverTimezone=UTC
    spring.datasource.username=root
    spring.datasource.password=123456
    spring.datasource.initialSize=20
    spring.datasource.minIdle=10
    spring.datasource.maxActive=100
    
    
    #Paging assistant configuration
    pagehelper.helper-dialect=mysql
    pagehelper.reasonable=true
    pagehelper.support-methods-arguments=true
    pagehelper.params=count=countSql

**Controller层部分**

/** * 进入个人通讯录界面-分页查询数据, * * @param * @return */
    @PostMapping("/queryAddressBookbyPage")
    @ApiOperation(value = "进入个人通讯录界面-分页查询数据")
    public ResponseResult queryAddressBookbyPage(@RequestBody RequestPam pam) { 
        logger.info("start AddressBookController.queryAddressBookbyPage");
        try { 
            Page page = addressBookService.queryAddressBookbyPage(pam);
            return ResponseResult.success(page, ConstantsUtil.QUERY_SUCCESS);
        } catch (Exception e) { 
            logger.error(e.getMessage(), e);
            return ResponseResult.error(ConstantsUtil.OPERATE_ERROR);
        }
    }

**service层**

public Page queryAddressBookbyPage(RequestPam pam) { 
        int pageNum = pam.getPageNo();
        int pageSize = pam.getSize();
        PageHelper.startPage(pageNum, pageSize);
        List<AddressBookPojo> list = addressBookPojoMapper.queryAddressBookbyPage(pam);
        for (AddressBookPojo addressBookPojo : list) { 
            addressBookPojo.setAllDeptName(addressBookPojo.getAllDeptName().replaceAll("-", " "));
        }
        return PageUtils.getPageResult(pam, new PageInfo<AddressBookPojo>(list));
    }

Page类

public class Page implements Serializable { 
        private static final long serialVersionUID = 1L;
        private int pageNo;//当前页
        private int pageSize;//当前页大小
        private long totalSize;//记录总数
        private int totalPages;//页码总数
        private Object value;
        
        /**省略set()\ get() **/
         
        public void setPageDetail(Object value, Integer totalNum, Integer pageNo, Integer pageSize) { 
            this.value = value;
            this.totalSize = totalNum;
            this.pageNo = pageNo;
            this.pageSize = pageSize;
            this.totalPages = totalNum / pageSize + 1;
        }
    }

**PageUtils**

public class PageUtils { 
        public static Page getPageResult(RequestPam pam, PageInfo<?> pageInfo) { 
            Page page = new Page();
            page.setPageNo(pageInfo.getPageNum());
            page.setPageSize(pageInfo.getPageSize());
            page.setTotalSize(pageInfo.getTotal());
            page.setTotalPages(pageInfo.getPages());
            page.setValue(pageInfo.getList());
            return page;
        }
    }

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