spring boot yml整合pagehelper的几种方式和问题

这是一个简单的SpringBoot整合实例
利用spring boot整合pagehelper实现分页功能
会介绍两种种整合方式(主要讲方式，完整代码在其他地方可以看到，我这里只贴出关键代码) 以及里面需要注意的问题
1：完全采用配置（重点介绍）
2：配置+代码configuration
3：完全代码实现
1：完全采用配置整合pagehelper

首先是pom.xml ，加入相应的依赖

<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0modelVersion>
    
    <parent>
        <groupId>org.springframework.bootgroupId>
        <artifactId>spring-boot-starter-parentartifactId>
        <version>1.5.1.RELEASEversion>
    parent>

    <groupId>com.mes.cloudgroupId>
    <artifactId>mes-cloud-starterartifactId>
    <package>jarpackage>
    <properties>
        <java.version>1.8java.version>
    properties>

    <version>1.0-SNAPSHOTversion>
        <dependencies>
            <dependency>
                <groupId>org.springframework.cloudgroupId>
                <artifactId>spring-cloud-dependenciesartifactId>
                <version>Camden.SR5version>
                <type>pomtype>
                <scope>importscope>
            dependency>
             
            <dependency>
                  <groupId>org.springframework.bootgroupId>
                  <artifactId>spring-boot-starter-webartifactId>
            dependency>
            
            <dependency>
                <groupId>org.mybatis.spring.bootgroupId>
                <artifactId>mybatis-spring-boot-starterartifactId>
                <version>1.3.1version>
            dependency>
            
            <dependency>
                <groupId>com.github.pagehelpergroupId>
                <artifactId>pagehelperartifactId>
                <version>5.1.0version>
            dependency>
             
              
            <dependency>
                <groupId>com.github.pagehelpergroupId>
                <artifactId>pagehelper-spring-boot-autoconfigureartifactId>
                <version>1.1.1version>
            dependency>
              
            <dependency>
                <groupId>com.github.pagehelpergroupId>
                <artifactId>pagehelper-spring-boot-starterartifactId>
                <version>1.2.3version>
            dependency>
        dependencies>
project>

接着在src/main/resources目录下新建一个application.yml文件

#mybatis配置 第一种和第二种需要 第三种不需要
mybatis:
  #mapper.xml文件位置
  mapper-locations: classpath*:mapper/*.xml
  check-config-location: true
  #对应mapper的实体类
  type-aliases-package: com.mes.cloud.**.dto

#pagehelper分页配置 第二种和第三种不需要 重点讲的第一种需要
pagehelper:
    helperDialect: mysql
    reasonable: true
    supportMethodsArguments: true
    params: count=countSql

下面是启动的入口代码，跟其他的启动没有区别

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.core.env.Environment;

import java.net.InetAddress;
import java.net.UnknownHostException;

/**
 * Created by pact on 2018/1/24.
 */
@SpringBootApplication
public class CcsApplication {

    private static final Logger LOGGER = LoggerFactory.getLogger(CcsApplication.class);

    public static void main(String[] args) throws UnknownHostException {
        SpringApplication app = new SpringApplication(CcsApplication.class);
        Environment env = app.run(args).getEnvironment();
        LOGGER.info("\n----------------------------------------------------------\n\t" +
                        "Application '{}' is running! Access URLs:\n\t" +
                        "Local: \t\thttp://localhost:{}\n\t" +
                        "External: \thttp://{}:{}\n\t" +
                        "Profile(s): \t{}\n----------------------------------------------------------",
                env.getProperty("spring.application.name"),
                env.getProperty("server.port"),
                InetAddress.getLocalHost().getHostAddress(),
                env.getProperty("server.port"),
                env.getActiveProfiles());
    }
}

启动以后就完成pagehelper的整合了:
2：完全代码实现

import java.util.Properties;

import org.apache.ibatis.plugin.Interceptor;
import org.mybatis.spring.SqlSessionFactoryBean;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;

import com.github.pagehelper.PageHelper;

import javax.sql.DataSource;

/**
 *  Created by pact on 2018/1/24
 */

@Configuration
@ComponentScan
public class MyBatisConfig {

    @Autowired
    private DataSource dataSource;
    /**
     *  第三种方式 代码中指定xml和实体类的对应关系
    */
    @Bean(name = "sqlSessionFactory")
    public SqlSessionFactoryBean sqlSessionFactory(ApplicationContext applicationContext) throws Exception {
        SqlSessionFactoryBean sessionFactory = new SqlSessionFactoryBean();
        sessionFactory.setDataSource(dataSource);
        // sessionFactory.setPlugins(new Interceptor[]{new PageInterceptor()});
        sessionFactory.setMapperLocations(applicationContext.getResources("classpath*:mapper/*.xml"));
        org.apache.ibatis.session.Configuration configuration =  sessionFactory.getObject().getConfiguration();
        configuration.setMapUnderscoreToCamelCase(true);
        sessionFactory.setConfiguration(configuration);
        Interceptor[] interceptor =new PageHelper[1];
        interceptor[0] = pageHelper();
        sessionFactory.setPlugins(interceptor);
        return sessionFactory;
    }
    /**
     *  第二种方式 在代码中指定pagehelper的配置
    */
    @Bean
    public PageHelper pageHelper() {
        PageHelper pageHelper = new PageHelper();
        Properties p = new Properties();
        p.setProperty("offsetAsPageNum", "true");
        p.setProperty("rowBoundsWithCount", "true");
        p.setProperty("reasonable", "true");
        p.setProperty("dialect", "mysql"); // 配置mysql数据库
        pageHelper.setProperties(p);
        return pageHelper;
    }

}

其实整合pagehelper很简单，但是采用第一种方式的时候一定要特别注意依赖jar包的兼容性问题，不然会包很奇怪的问题，第二种和第三种就不存在这个问题。