本教程主要详细讲解SpringBoot整合MyBatis使用PageHelper进行数据查询并分页功能!
基础环境
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| 技术 | 版本 |
|---|
| Java | 1.8+ |
| SpringBoot | 2.x.x |
| MyBatis | 3.5.x |
| PageHelper | 5.x.x |
创建项目
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mvn archetype:generate -DgroupId=com.edurt.sli.slismh -DartifactId=spring-learn-integration-springboot-mybatis-pagehelper -DarchetypeArtifactId=maven-archetype-quickstart -Dversion=1.0.0 -DinteractiveMode=false
<?xml version="1.0" encoding="UTF-8"?>
<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">
<parent>
<artifactId>spring-learn-integration-springboot-mybatis</artifactId>
<groupId>com.edurt.sli</groupId>
<version>1.0.0</version>
</parent>
<modelVersion>4.0.0</modelVersion>
<artifactId>spring-learn-integration-springboot-mybatis-pagehelper</artifactId>
<name>SpringBoot整合MyBatis教程(PageHelper版)</name>
<properties>
<system.java.version>1.8</system.java.version>
<plugin.maven.compiler.version>3.3</plugin.maven.compiler.version>
<springboot.common.version>2.1.3.RELEASE</springboot.common.version>
<springboot.mybatis.common.version>2.1.1</springboot.mybatis.common.version>
<mysql.version>5.1.47</mysql.version>
<lombox.version>1.18.8</lombox.version>
<pagehelper.version>1.2.5</pagehelper.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
<version>${springboot.common.version}</version>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<version>${springboot.common.version}</version>
</dependency>
<dependency>
<groupId>org.mybatis.spring.boot</groupId>
<artifactId>mybatis-spring-boot-starter</artifactId>
<version>${springboot.mybatis.common.version}</version>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>${mysql.version}</version>
</dependency>
<dependency>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
<version>${lombox.version}</version>
</dependency>
<dependency>
<groupId>com.github.pagehelper</groupId>
<artifactId>pagehelper-spring-boot-starter</artifactId>
<version>${pagehelper.version}</version>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
<version>${springboot.common.version}</version>
<configuration>
<fork>true</fork>
</configuration>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>${plugin.maven.compiler.version}</version>
<configuration>
<source>${system.java.version}</source>
<target>${system.java.version}</target>
</configuration>
</plugin>
</plugins>
</build>
</project>
pagehelper-spring-boot-starter:该starter是我们使用MyBatis集成PageHelper插件的依赖整合包
- 在
src/main/java目录下新建com.edurt.sli.slismh目录并在该目录下新建SpringBootMyBatisPageHelperIntegration类文件,在文件输入以下内容
package com.edurt.sli.slismh;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.stereotype.Component;
@SpringBootApplication
@Component(value = "com.edurt.sli.slismh")
public class SpringBootMyBatisPageHelperIntegration {
public static void main(String[] args) {
SpringApplication.run(SpringBootMyBatisPageHelperIntegration.class, args);
}
}
构建基本使用的SQL文件
—
在src/main目录下新建example.sql文件,键入以下内容
create database spring;
use spring;
drop table if exists user;
create table user
(
id int(20) auto_increment,
userName varchar(20),
primary key (id)
)
default charset 'utf8';
insert into user(userName) value ('1');
insert into user(userName) value ('2');
insert into user(userName) value ('3');
insert into user(userName) value ('4');
insert into user(userName) value ('5');
insert into user(userName) value ('6');
insert into user(userName) value ('7');
insert into user(userName) value ('8');
insert into user(userName) value ('9');
insert into user(userName) value ('10');
insert into user(userName) value ('11');
我们运行该sql文件进行创建数据库/数据表操作.
配置MyBatis数据源
—
- 在
/src/main/java/com/edurt/sli/slismh目录下创建config目录,并在该目录下新建MyBatisPageHelperConfig配置类,键入以下代码
package com.edurt.sli.slismh.config;
import com.github.pagehelper.PageInterceptor;
import org.apache.ibatis.session.SqlSessionFactory;
import org.mybatis.spring.SqlSessionFactoryBean;
import org.mybatis.spring.annotation.MapperScan;
import org.mybatis.spring.boot.autoconfigure.ConfigurationCustomizer;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.jdbc.datasource.DataSourceTransactionManager;
import javax.sql.DataSource;
import java.util.Properties;
@Configuration
@MapperScan(value = {"com.edurt.sli.slismh.mapper"})
public class MyBatisPageHelperConfig {
@Bean(name = "transactionManager")
public DataSourceTransactionManager transactionManager(
@Qualifier("dataSource") DataSource dataSource) {
return new DataSourceTransactionManager(dataSource);
}
@Bean(name = "sqlSessionFactory")
@ConditionalOnMissingBean(name = "sqlSessionFactory")
public SqlSessionFactory sqlSessionFactory(@Qualifier("dataSource") DataSource dataSource) throws Exception {
final SqlSessionFactoryBean sessionFactory = new SqlSessionFactoryBean();
sessionFactory.setDataSource(dataSource);
PageInterceptor pageInterceptor = new PageInterceptor();
Properties properties = new Properties();
properties.setProperty("helperDialect", "mysql");
properties.setProperty("reasonable", "true");
properties.setProperty("params", "pageNum=pageNum;pageSize=pageSize");
pageInterceptor.setProperties(properties);
sessionFactory.setPlugins(pageInterceptor);
return sessionFactory.getObject();
}
@Bean
ConfigurationCustomizer mybatisConfigurationCustomizer() {
return configuration -> {
configuration.setMapUnderscoreToCamelCase(Boolean.TRUE);
configuration.setLogPrefix("com.edurt.sli.slismh");
};
}
}
我们需要注意的是sqlSessionFactory代码中的第33-39行,这些是配置MyBatis支持PageHelper插件的代码部分,具体的配置信息可以参考PageHelper官方网站的详细配置参数,在此我们只是配置一些常用参数
@MapperScan注解用于指定我们Mapper文件所在的位置
配置Mapper支持数据查询
—
- 在
/src/main/resources资源目录下创建一个application.properties的配置文件,用于数据库连接配置,键入以下内容
server.port=8989
spring.datasource.url=jdbc:mysql://localhost:3306/spring?useSSL=false
spring.datasource.driver-class-name=com.mysql.jdbc.Driver
spring.datasource.username=root
spring.datasource.password=123456
- 在
/src/main/java/com/edurt/sli/slismh目录下创建model目录,并在该目录下新建UserModel实体类,键入以下代码
package com.edurt.sli.slismh.model;
import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;
import lombok.ToString;
@Data
@ToString
@AllArgsConstructor
@NoArgsConstructor
public class UserModel {
private Integer id;
private String userName;
}
- 在
/src/main/java/com/edurt/sli/slismh目录下创建mapper目录,并在该目录下新建UserMapper映射类,用于映射数据库和实体类,键入以下代码
package com.edurt.sli.slismh.mapper;
import com.edurt.sli.slismh.model.UserModel;
import com.github.pagehelper.Page;
import org.apache.ibatis.annotations.Mapper;
import org.apache.ibatis.annotations.Result;
import org.apache.ibatis.annotations.Results;
import org.apache.ibatis.annotations.Select;
@Mapper
public interface UserMapper {
@Results(value = {
@Result(property = "id", column = "id", id = true),
@Result(property = "userName", column = "username")
})
@Select(value = "SELECT id, username FROM user")
Page<UserModel> getUsers();
}
我们只需要提供一个查询方法即可
- 接下来我们在
/src/test/java目录下新建com.edurt.sli.slismh目录,并在该目录下新建UserMapperTest测试文件,键入以下内容
package com.edurt.sli.slismh.mapper;
import com.edurt.sli.slismh.SpringBootMyBatisPageHelperIntegration;
import com.github.pagehelper.PageHelper;
import org.junit.After;
import org.junit.Before;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.autoconfigure.jdbc.AutoConfigureTestDatabase;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
@RunWith(SpringJUnit4ClassRunner.class)
@AutoConfigureTestDatabase(replace = AutoConfigureTestDatabase.Replace.NONE)
@SpringBootTest(
classes = SpringBootMyBatisPageHelperIntegration.class,
webEnvironment = SpringBootTest.WebEnvironment.RANDOM_PORT
)
public class UserMapperTest {
@Autowired
private UserMapper userMapper;
@Before
public void before() {
}
@After
public void after() {
}
@Test
public void testGetUsers() {
Integer pageNo = 1, pageSize = 5;
PageHelper.startPage(pageNo, pageSize);
System.out.println(this.userMapper.getUsers());
}
}
我们在@Before中初始化了一个新的实体信息
然后使用testGetUsers方法进行测试我们UserMapper提供的查询分页是否有效,注意此时会出现一个错误,信息如下:
Caused by: java.lang.RuntimeException: 在系统中发现了多个分页插件，请检查系统配置!
at com.github.pagehelper.PageHelper.skip(PageHelper.java:55)
at com.github.pagehelper.PageInterceptor.intercept(PageInterceptor.java:92)
at org.apache.ibatis.plugin.Plugin.invoke(Plugin.java:61)
at com.sun.proxy.$Proxy95.query(Unknown Source)
at com.github.pagehelper.PageInterceptor.executeAutoCount(PageInterceptor.java:201)
at com.github.pagehelper.PageInterceptor.intercept(PageInterceptor.java:113)
at org.apache.ibatis.plugin.Plugin.invoke(Plugin.java:61)
at com.sun.proxy.$Proxy95.query(Unknown Source)
at org.apache.ibatis.session.defaults.DefaultSqlSession.selectList(DefaultSqlSession.java:147)
... 53 more
这个错误是因为我们使用的是pagehelper集成的springboot的starter插件,该插件默认会配置一个pagehelper.,而我们也在MyBatisPageHelperConfig代码中进行了配置,我们只需要注释以下代码即可
PageInterceptor pageInterceptor = new PageInterceptor();
Properties properties = new Properties();
properties.setProperty("helperDialect", "mysql");
properties.setProperty("reasonable", "true");
properties.setProperty("params", "pageNum=pageNum;pageSize=pageSize");
pageInterceptor.setProperties(properties);
sessionFactory.setPlugins(pageInterceptor);
注意我们使用Page<E>后不需要在使用PageInfo<E>去修饰数据结构了.我们运行后返回的数据如下
Page{count=true, pageNum=1, pageSize=5, startRow=0, endRow=5, total=11, pages=3, reasonable=false, pageSizeZero=false}[UserModel(id=2, userName=1), UserModel(id=3, userName=2), UserModel(id=4, userName=3), UserModel(id=5, userName=4), UserModel(id=6, userName=5)]
数据排序(orderBy)
—
使用PageHelper对数据排序分为两种
- 直接在
@Select中增加order by字段
- 在
PageHelper设置排序字段(该字段对应数据表中的字段),代码如下
@Test
public void testGetUsersOrderBy() {
Integer pageNo = 1, pageSize = 5;
PageHelper.startPage(pageNo, pageSize);
PageHelper.orderBy("userName");
System.out.println(this.userMapper.getUsers());
}
我们运行后返回的数据如下
Page{count=true, pageNum=1, pageSize=5, startRow=0, endRow=5, total=11, pages=3, reasonable=false, pageSizeZero=false}[UserModel(id=2, userName=1), UserModel(id=11, userName=10), UserModel(id=12, userName=11), UserModel(id=3, userName=2), UserModel(id=4, userName=3)]
如果使用倒序或者顺序则将orserBy参数进行拼接,代码如下
@Test
public void testGetUsersOrderByCustom() {
Integer pageNo = 1, pageSize = 5;
PageHelper.startPage(pageNo, pageSize);
PageHelper.orderBy("userName desc");
System.out.println(this.userMapper.getUsers());
}
我们运行后返回的数据如下
Page{count=true, pageNum=1, pageSize=5, startRow=0, endRow=5, total=11, pages=3, reasonable=false, pageSizeZero=false}[UserModel(id=10, userName=9), UserModel(id=9, userName=8), UserModel(id=8, userName=7), UserModel(id=7, userName=6), UserModel(id=6, userName=5)]
也许大家会有以为为什么我们看到我们每次返回的是乱的,这是因为我们的userName是字符串类型的,并不是数字类型,所以我们得到的查询结果是没有问题的!
数据分组(groupBy)
—
PageHelper没有帮我们进行分组配置,直接在@Select中增加group by字段
打包文件部署
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mvn clean package -Dmaven.test.skip=true -X
运行打包后的文件即可
java -jar target/spring-learn-integration-springboot-mybatis-pagehelper-1.0.0.jar
源码地址
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