在使用pagehelper 的时候，由于pagehelper有不同版本（有的是基于sping 的 ，有的是基于spingboot 的）
    如果直接在maven依赖中直接引用springboot pagehelper，使用springBoot 版本的PH 是不需要在注入pagehelper Bean 的，可以直接在程序中使用

    但是如果只是在maven中引入PH 的依赖，那么就需要对pagehelper 进行Bean注入，下面是实现Bean注入的代码：

    1. @Configuration
    2. public class MybatisConf {
    3.     @Bean
    4.     public PageHelper pageHelper() {
    5.         PageHelper pageHelper = new PageHelper();
    6.         Properties p = new Properties();
    7.         p.setProperty("offsetAsPageNum", "true");
    8.         p.setProperty("rowBoundsWithCount", "true");
    9.         p.setProperty("reasonable", "true");
    10.         pageHelper.setProperties(p);
    11.         return pageHelper;

    当然，如果项目本身就是springboot项目的话，最好还是使用spring boot版本的pagehelper.

    在如下配置中，yml中的文件能够被springboot自动进行加载

    1. ##
    2. server:
    3.   port: 8080
    4. ##
    5. spring:
    6.   #数据源配置
    7.   datasource:
    8.     username: root
    9.     password: 
    10.     url: jdbc:mysql://localhost:3306/nongchatea?useUnicode=true&characterEncoding=utf-8&useSSL=true&serverTimezone=UTC
    11.     driver-class-name: com.mysql.cj.jdbc.Driver
    12.     type: com.alibaba.druid.pool.DruidDataSource
    13.     #druid 配置
    14.     druid:
    15.       initialSize: 5
    16.       minIdle: 5
    17.       maxActive: 20
    18.       maxWait: 60000
    19.       timeBetweenEvictionRunsMillis: 60000
    20.       minEvictableIdleTimeMillis: 300000
    21.       validationQuery: SELECT 1 FROM DUAL
    22.       testWhileIdle: true
    23.       testOnBorrow: false
    24.       testOnReturn: false
    25.       poolPreparedStatements: true
    26.   #自动设置json返回格式
    27.   jackson:
    28.     #日期格式化
    29.     date-format: yyyy-MM-dd
    30.     time-zone: GMT+8
    31.     #设置空如何序列化
    32.     default-property-inclusion: non_null
    33.     serialization:
    34.       #格式化输出
    35.       indent_output: true
    36.       #忽略无法转换的对象
    37.       fail_on_empty_beans: false
    38.     deserialization:
    39.       #允许对象忽略json中不存在的属性
    40.       fail_on_unknown_properties: false
    41.     parser:
    42.       #允许出现特殊字符和转义符
    43.       allow_unquoted_control_chars: true
    44.       #允许出现单引号
    45.       allow_single_quotes: true
    46.   #文件上传限制
    47.   servlet:
    48.     multipart:
    49.       max-request-size: 100MB
    50.       max-file-size: 50MB
    53. ##mybatis设置
    54. mybatis:
    55.   mapper-locations: classpath:mapping/*Mapper.xml
    56.   type-aliases-package: com.example.springbootmybatis.pojo
    57.   configuration:
    58.     log-impl: org.apache.ibatis.logging.stdout.StdOutImpl
    59.     map-underscore-to-camel-case: true
    61. ##pagehelper设置
    62. pagehelper:
    63.   helperDialect: mysql
    64.   reasonable: true
    65.   supportMethodsArguments: true
    66.   params: count=countSql
    1. <?xml version="1.0" encoding="UTF-8"?>
    2. <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    3.          xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    4.     <modelVersion>4.0.0</modelVersion>
    5.     <parent>
    6.         <groupId>org.springframework.boot</groupId>
    7.         <artifactId>spring-boot-starter-parent</artifactId>
    8.         <version>2.5.3</version>
    9.         <relativePath/> <!-- lookup parent from repository -->
    10.     </parent>
    11.     <groupId>com.example</groupId>
    12.     <artifactId>SpringBootMybatis</artifactId>
    13.     <version>0.0.1-SNAPSHOT</version>
    14.     <name>SpringBootMybatis</name>
    15.     <description>Demo project for Spring Boot</description>
    16.     <properties>
    17.         <java.version>11</java.version>
    18.     </properties>
    19.     <dependencies>
    20.         <dependency>
    21.             <groupId>org.springframework.boot</groupId>
    22.             <artifactId>spring-boot-starter-data-jdbc</artifactId>
    23.         </dependency>
    24.         <dependency>
    25.             <groupId>org.springframework.boot</groupId>
    26.             <artifactId>spring-boot-starter-web</artifactId>
    27.         </dependency>
    28.         <dependency>
    29.             <groupId>org.mybatis.spring.boot</groupId>
    30.             <artifactId>mybatis-spring-boot-starter</artifactId>
    31.             <version>2.2.0</version>
    32.         </dependency>
    34.         <dependency>
    35.             <groupId>mysql</groupId>
    36.             <artifactId>mysql-connector-java</artifactId>
    37.             <scope>runtime</scope>
    38.         </dependency>
    39. <!--        注意使用springboot适配的druid-->
    40.         <dependency>
    41.             <groupId>com.alibaba</groupId>
    42.             <artifactId>druid-spring-boot-starter</artifactId>
    43.             <version>1.2.4</version>
    44.         </dependency>
    45.         <dependency>
    46.             <groupId>org.projectlombok</groupId>
    47.             <artifactId>lombok</artifactId>
    48.             <optional>true</optional>
    49.         </dependency>
    50.         <dependency>
    51.             <groupId>org.springframework.boot</groupId>
    52.             <artifactId>spring-boot-starter-test</artifactId>
    53.             <scope>test</scope>
    54.         </dependency>
    55.         <dependency>
    56.             <groupId>com.fasterxml.jackson.core</groupId>
    57.             <artifactId>jackson-core</artifactId>
    58.         </dependency>
    59.         <dependency>
    60.             <groupId>log4j</groupId>
    61.             <artifactId>log4j</artifactId>
    62.             <version>1.2.17</version>
    63.         </dependency>
    64.         <dependency>
    65.             <groupId>org.jetbrains</groupId>
    66.             <artifactId>annotations</artifactId>
    67.             <version>RELEASE</version>
    68.             <scope>compile</scope>
    69.         </dependency>
    70. <!--        注意使用springboot适配的pagehelper，否则需要自己注入bean-->
    71.         <dependency>
    72.             <groupId>com.github.pagehelper</groupId>
    73.             <artifactId>pagehelper-spring-boot-starter</artifactId>
    74.             <version>1.3.0</version>
    75.         </dependency>
    76.         <dependency>
    77.             <groupId>org.springframework.boot</groupId>
    78.             <artifactId>spring-boot-configuration-processor</artifactId>
    79.         </dependency>
    80.     </dependencies>
    82.     <build>
    83.         <plugins>
    84.             <plugin>
    85.                 <groupId>org.springframework.boot</groupId>
    86.                 <artifactId>spring-boot-maven-plugin</artifactId>
    87.                 <configuration>
    88.                     <excludes>
    89.                         <exclude>
    90.                             <groupId>org.projectlombok</groupId>
    91.                             <artifactId>lombok</artifactId>
    92.                         </exclude>
    93.                     </excludes>
    94.                 </configuration>
    95.             </plugin>
    96.         </plugins>
    97.     </build>
    99. </project>