springboot+mybatis多数据源配置（附源码，page helper分页配置）

本文链接：https://blog.youkuaiyun.com/zxc19854/article/details/107730578

测试的工作很大一部分时间都会花费在造测试数据上，尤其对于分布式系统。这种系统一般都是很多小组维护各自的模块，作为下游系统，如果要验证一些业务流程，数据必须来自上游系统的真实数据，所以我们维护了一个帮助测试同事造数的平台，这其中就涉及到 “多数据源的配置”

mybatis工作原理

创建SqlSessionFactoryBuilder对象，调用build(inputstream)方法读取并解析配置文件，返回SqlSessionFactory对象
由SqlSessionFactory创建SqlSession 对象
调用SqlSession中的api，传入Statement Id和参数，最后调用jdbc执行SQL语句，封装结果返回

实例

先配置两个库 teacher 、student

student.jdbc.url=jdbc:mysql://127.0.0.1:3306/student?serverTimezone=UTC&characterEncoding=UTF8&zeroDateTimeBehavior=convertToNull
jdbc.student.name=root
jdbc.student.password=root
        
teacher.jdbc.url=jdbc:mysql://127.0.0.1:3306/teacher?serverTimezone=UTC&characterEncoding=UTF8&zeroDateTimeBehavior=convertToNull
jdbc.teacher.name=root
jdbc.teacher.password=root

这里以student的Mybatis配置为例，
这里需要注意多数据源的配置需要指定的主数据源的，需要添加 @Primary，如果不配置主数据源，启动会报错

@Configuration
@MapperScan(basePackages = {"com.zl.demo.mapper.student"}, sqlSessionFactoryRef = "studentSqlSessionFactory")
public class StudentMybatisConfig {

    @Autowired
    private AppConfigBean appConfigBean;

    @Bean(name = "studentDataSource")
    DataSource mockDataSource() throws SQLException {
        DruidDataSource dataSource = new DruidDataSource();
        dataSource.setUrl(appConfigBean.getStudentJdbcUrl());
        dataSource.setDriverClassName(appConfigBean.getJdbcDriverClassName());
        dataSource.setUsername(appConfigBean.getJdbcStudentName());
        dataSource.setPassword(appConfigBean.getJdbcStudentPassword());
        dataSource.setFilters("stat");
        List<String> initSqls = new ArrayList<>();
        initSqls.add("set names utf8mb4");
        dataSource.setConnectionInitSqls(initSqls);
        dataSource.setMaxActive(appConfigBean.getJdbcMaxActive());
        dataSource.setInitialSize(appConfigBean.getJdbcInitialSize());
        return dataSource;
    }

    @Bean(name = "studentSqlSessionFactory")
    @Primary
    public SqlSessionFactory studentSqlSessionFactory() throws SQLException {
        SqlSessionFactoryBean factoryBean = new SqlSessionFactoryBean();
        factoryBean.setDataSource(mockDataSource());
        factoryBean.setTypeAliasesPackage("com.zl.deml.entity.student");
        // 分页插件
        PageHelper pageHelper = new PageHelper();
        Properties properties = new Properties();
        properties.setProperty("reasonable", "false");
        //properties.setProperty("supportMethodsArguments", "true");
        properties.setProperty("returnPageInfo", "check");
        properties.setProperty("params", "pageNum=start;count=countSql");
        pageHelper.setProperties(properties);
        // 添加插件
        factoryBean.setPlugins(new Interceptor[]{pageHelper});
        // 添加XML目录
        ResourcePatternResolver resolver = new PathMatchingResourcePatternResolver();
        try {
            factoryBean
                    .setMapperLocations(resolver.getResources("classpath*:/mybatis/student/*.xml"));
            return factoryBean.getObject();
        } catch (Exception e) {
            e.printStackTrace();
            throw new RuntimeException(e);
        }
    }

    @Bean(name = "studentTransactionManager")
    public DataSourceTransactionManager studentTransactionManager() {
        try {
            return new DataSourceTransactionManager(mockDataSource());
        } catch (SQLException e) {
            throw new RuntimeException(e);
        }
    }
}

其中有一段是对pageHelper 分页的配置，不需要的话可以删除。

测试数据

多数据源整合测试数据

{
    "teacher":[
        {
            "id":1,
            "name":"老师1",
            "sex":"男",
            "age":30
        },
        {
            "id":2,
            "name":"老师2",
            "sex":"女",
            "age":28
        },
        {
            "id":3,
            "name":"老师3",
            "sex":"女",
            "age":25
        }
    ],
    "students":[
        {
            "id":1,
            "name":"学生1",
            "sex":"女",
            "age":18
        },
        {
            "id":2,
            "name":"学生2",
            "sex":"女",
            "age":19
        },
        {
            "id":3,
            "name":"学生3",
            "sex":"男",
            "age":20
        },
        {
            "id":4,
            "name":"学生4",
            "sex":"男",
            "age":21
        }
    ]
}

分页的测数据

[
    {
        "students":{
            "id":3,
            "name":"学生3",
            "sex":"男",
            "age":20
        }
    },
    {
        "students":{
            "id":3,
            "name":"学生3",
            "sex":"男",
            "age":20
        }
    },
    {
        "students":{
            "id":3,
            "name":"学生3",
            "sex":"男",
            "age":20
        }
    }
]