Configuration注解

1.说明

Configuration注解的出现就是为了替换xml文件
java配置是通过@Configuration和@Bean注解实现了

@Configuration注解，声明当前是一个配置类，相当于是spring中的一个xml文件
@Bean 注解: 作用在方法上，声明当前方法的返回值是一个Bean

2.使用范例

数据库配置

package fama.cost.dao.datasource;

import com.baomidou.mybatisplus.annotation.DbType;
import com.baomidou.mybatisplus.annotation.IdType;
import com.baomidou.mybatisplus.core.MybatisConfiguration;
import com.baomidou.mybatisplus.core.config.GlobalConfig;
import com.baomidou.mybatisplus.extension.plugins.MybatisPlusInterceptor;
import com.baomidou.mybatisplus.extension.plugins.PaginationInterceptor;
import com.baomidou.mybatisplus.extension.plugins.inner.PaginationInnerInterceptor;
import com.baomidou.mybatisplus.extension.spring.MybatisSqlSessionFactoryBean;
import com.zaxxer.hikari.HikariDataSource;
import fama.cost.common.utils.Constants;
import fama.cost.dao.utils.PropertyUtils;
import org.apache.ibatis.logging.stdout.StdOutImpl;
import org.apache.ibatis.mapping.DatabaseIdProvider;
import org.apache.ibatis.mapping.VendorDatabaseIdProvider;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.type.JdbcType;
import org.mybatis.spring.SqlSessionTemplate;
import org.mybatis.spring.annotation.MapperScan;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.core.io.support.PathMatchingResourcePatternResolver;
import org.springframework.core.io.support.ResourcePatternResolver;
import org.springframework.jdbc.datasource.DataSourceTransactionManager;

import java.util.Properties;



@Configuration
@MapperScan("fama.cost.*.mapper")
public class SpringConnectionFactory {

    private static final Logger logger = LoggerFactory.getLogger(SpringConnectionFactory.class);

    @Bean
    public MybatisPlusInterceptor paginationInterceptor() {
        MybatisPlusInterceptor interceptor = new MybatisPlusInterceptor();
        interceptor.addInnerInterceptor(new PaginationInnerInterceptor(DbType.MYSQL));
        return interceptor;
    }

    @Bean(destroyMethod="")
    public HikariDataSource dataSource() {

        HikariDataSource hikariDataSource = new HikariDataSource();
        
        hikariDataSource.setDriverClassName(PropertyUtils.getString(Constants.SPRING_DATASOURCE_DRIVER_CLASS_NAME));
        hikariDataSource.setJdbcUrl(PropertyUtils.getString(Constants.SPRING_DATASOURCE_URL));
        hikariDataSource.setUsername(PropertyUtils.getString(Constants.SPRING_DATASOURCE_USERNAME));
        hikariDataSource.setPassword(PropertyUtils.getString(Constants.SPRING_DATASOURCE_PASSWORD));
        hikariDataSource.setConnectionTestQuery(PropertyUtils.getString(Constants.SPRING_DATASOURCE_VALIDATION_QUERY,"SELECT 1"));
        hikariDataSource.setConnectionTimeout(PropertyUtils.getLong(Constants.SPRING_DATASOURCE_CONNECTION_TIMEOUT,30000));
        hikariDataSource.setMaximumPoolSize(PropertyUtils.getInt(Constants.SPRING_DATASOURCE_MAX_POOL_SIZE, 10));
        hikariDataSource.setIdleTimeout(PropertyUtils.getLong(Constants.SPRING_DATASOURCE_IDLE_TIMEOUT,180000));
        hikariDataSource.setAutoCommit(PropertyUtils.getBoolean(Constants.SPRING_DATASOURCE_DEFAULT_AUTO_COMMIT,true));
        hikariDataSource.setMaxLifetime(PropertyUtils.getLong(Constants.SPRING_DATASOURCE_MAX_LIFE_TIME,1800000));
        return hikariDataSource;
    }

    @Bean
    public DataSourceTransactionManager transactionManager() {
        return new DataSourceTransactionManager(dataSource());
    }

    @Bean
    public SqlSessionFactory sqlSessionFactory() throws Exception {
        MybatisConfiguration configuration = new MybatisConfiguration();
//        configuration.setLogImpl(StdOutImpl.class);
        configuration.setMapUnderscoreToCamelCase(true);
        configuration.setCacheEnabled(false);
        configuration.setCallSettersOnNulls(true);
        configuration.setJdbcTypeForNull(JdbcType.NULL);
        configuration.addInterceptor(paginationInterceptor());
        MybatisSqlSessionFactoryBean sqlSessionFactoryBean = new MybatisSqlSessionFactoryBean();
        sqlSessionFactoryBean.setConfiguration(configuration);
        sqlSessionFactoryBean.setDataSource(dataSource());

        GlobalConfig.DbConfig dbConfig = new GlobalConfig.DbConfig();
        dbConfig.setIdType(IdType.AUTO);
        GlobalConfig globalConfig = new GlobalConfig();
        globalConfig.setDbConfig(dbConfig);
        sqlSessionFactoryBean.setGlobalConfig(globalConfig);
        sqlSessionFactoryBean.setTypeAliasesPackage("fama.cost.dao.entity");
        ResourcePatternResolver resolver = new PathMatchingResourcePatternResolver();
        sqlSessionFactoryBean.setMapperLocations(resolver.getResources("fama/cost/dao/mapper/*Mapper.xml"));
//        sqlSessionFactoryBean.setTypeEnumsPackage("fama.cost.*.fama.cost.api.enums");
        sqlSessionFactoryBean.setTypeEnumsPackage("fama.cost.*.enums");
        sqlSessionFactoryBean.setDatabaseIdProvider(databaseIdProvider());
        return sqlSessionFactoryBean.getObject();
    }

    @Bean
    public SqlSession sqlSession() throws Exception{
        return new SqlSessionTemplate(sqlSessionFactory());
    }

    @Bean
    public DatabaseIdProvider databaseIdProvider(){
        DatabaseIdProvider databaseIdProvider = new VendorDatabaseIdProvider();
        Properties properties = new Properties();
        properties.setProperty("MySQL", "mysql");
        databaseIdProvider.setProperties(properties);
        return databaseIdProvider;
    }
}

2.sql 关系

dataSource -> sqlSessionFactory -> sqlSession

dataSource -> transactionManager