springboot学习(二十七) @ConditionalOnProperty的使用

@ConditionalOnProperty一般加在@Configurarion、@Component配置的类上或@Bean配置的方法上，表示满足获取到某些配置文件信息后才会配置或加载。

@ConditionalOnProperty源码如下:

@Retention(RetentionPolicy.RUNTIME)
@Target({ElementType.TYPE, ElementType.METHOD})
@Documented
@Conditional({OnPropertyCondition.class})
public @interface ConditionalOnProperty {
	//获取对应property名称的值，与name不可同时使用
    String[] value() default {}; 
 	//property名称的前缀，可以不配置
    String prefix() default "";
 	//配置信息的完整名称或部分名称（可与prefix组合使用，组成完整的property名称），与value不可同时使用
    String[] name() default {};
 	//可与name组合使用，比较获取到的属性值与havingValue给定的值是否相同，相同才加载配置
    String havingValue() default "";
 	//缺少该property时是否可以加载。如果为true，没有该property也会正常加载；反之报错
    boolean matchIfMissing() default false;
}

使用场景：
例如项目框架中配置了单数据源配置方式、多数据源配置方式，可以使用配置文件的一个配置来控制，而不必在某些项目使用单数据源，而某些使用多数据源时改代码了。

多数据源时：

package com.iscas.biz.mp.config.db.multi;


@Slf4j
@ConditionalOnProperty(name = "spring.datasource.multi", havingValue = "true", matchIfMissing = false)
@Configuration
public class DruidConfiguration {

    //mysql1

    @Value("${spring.datasource.druid.mysql1.filters:stat,wall,logback}")
    private String filters;
    @Value("${spring.datasource.druid.mysql1.filter.stat.log-slow-sql:true}")
    private boolean logslowSql;
    @Value("${spring.datasource.druid.mysql1.filter.stat.merge-sql:true}")
    private boolean mergeSql;
    @Value("${spring.datasource.druid.mysql1.filter.stat.slow-sql-millis:200}")
    private long slowSqlMill;

    //mysql2

    @Value("${spring.datasource.druid.mysql2.filters:stat,wall,logback}")
    private String filters2;
    @Value("${spring.datasource.druid.mysql2.filter.stat.log-slow-sql:true}")
    private boolean logslowSql2;
    @Value("${spring.datasource.druid.mysql2.filter.stat.merge-sql:true}")
    private boolean mergeSql2;
    @Value("${spring.datasource.druid.mysql2.filter.stat.slow-sql-millis:200}")
    private long slowSqlMill2;

    @Autowired
    private DruidMultiDatasource1Properties datasource1Properties;
    @Autowired
    private DruidMultiDatasource2Properties datasource2Properties;


    @Bean(name = "mysql1")
    @ConditionalOnProperty(name = "spring.datasource.druid.mysql1.name", havingValue = "mysql1",
            matchIfMissing = true)
//    @ConfigurationProperties(prefix = "spring.datasource.druid.mysql1")
    public DataSource db1(){
        DruidDataSource datasource = (DruidDataSource) datasource1Properties.initializeDataSourceBuilder().build();

        //        datasource.setUseGlobalDataSourceStat(useGlobalDataSourceStat);
        try {
            datasource.setFilters(filters);
        } catch (SQLException e) {
            log.error("druid configuration initialization filter: "+ e);
        }
        datasource.setProxyFilters(Arrays.asList(statFilter(),logFilter()));
//        datasource.setConnectionProperties(connectionProperties);
        return datasource;
    }


    @Bean(name = "mysql2")
    @ConditionalOnProperty(name = "spring.datasource.druid.mysql2.name", havingValue = "mysql2",
            matchIfMissing = true)
//    @ConfigurationProperties(prefix = "spring.datasource.druid.mysql2")
    public DataSource db2(){
        DruidDataSource datasource = (DruidDataSource) datasource2Properties.initializeDataSourceBuilder().build();
        try {
            datasource.setFilters(filters2);
        } catch (SQLException e) {
            log.error("druid configuration initialization filter: "+ e);
        }
        datasource.setProxyFilters(Arrays.asList(statFilter(),logFilter()));
//        datasource.setConnectionProperties(connectionProperties);
        return datasource;
    }

    /**
     * 动态数据源配置
     * @return
     */
    @Bean
    @Primary
    public DataSource multipleDataSource (@Qualifier("mysql1") DataSource db1,
                                          @Qualifier("mysql2") DataSource db2) {

        DynamicDataSource dynamicDataSource = new DynamicDataSource();
        Map< Object, Object > targetDataSources = new HashMap<>(2 << 2);
        targetDataSources.put(DbTypeEnum.db1.getValue(), db1 );
        targetDataSources.put(DbTypeEnum.db2.getValue(), db2);
        dynamicDataSource.setTargetDataSources(targetDataSources);
        dynamicDataSource.setDefaultTargetDataSource(db1);
        return dynamicDataSource;
    }

    @Bean
    @Primary
    public SqlSessionFactory sqlSessionFactory() throws Exception {
        MybatisSqlSessionFactoryBean sqlSessionFactory = new MybatisSqlSessionFactoryBean();
        sqlSessionFactory.setDataSource(multipleDataSource(db1(),db2()));
//        sqlSessionFactory.setDataSource(multipleDataSource);
        //sqlSessionFactory.setMapperLocations(new PathMatchingResourcePatternResolver().getResources("classpath:/mapper/*/*Mapper.xml"));

        MybatisConfiguration configuration = new MybatisConfiguration();
        //configuration.setDefaultScriptingLanguage(MybatisXMLLanguageDriver.class);
        configuration.setJdbcTypeForNull(JdbcType.NULL);
        configuration.setMapUnderscoreToCamelCase(true);
        configuration.setCacheEnabled(false);
        sqlSessionFactory.setConfiguration(configuration);
//        sqlSessionFactory.setPlugins(new Interceptor[]{ //PerformanceInterceptor(),OptimisticLockerInterceptor()
//                paginationInterceptor() //添加分页功能
//        });
//        sqlSessionFactory.setGlobalConfig(globalConfiguration());
        return sqlSessionFactory.getObject();
    }




    @Bean
    @Primary
    public StatFilter statFilter(){
        StatFilter statFilter = new StatFilter();
        statFilter.setSlowSqlMillis(slowSqlMill);
        statFilter.setLogSlowSql(logslowSql);
        statFilter.setMergeSql(mergeSql);
        return statFilter;
    }

    @Bean
    public Slf4jLogFilter logFilter(){
        Slf4jLogFilter filter = new Slf4jLogFilter();
//        filter.setResultSetLogEnabled(false);
//        filter.setConnectionLogEnabled(false);
//        filter.setStatementParameterClearLogEnable(false);
//        filter.setStatementCreateAfterLogEnabled(false);
//        filter.setStatementCloseAfterLogEnabled(false);
//        filter.setStatementParameterSetLogEnabled(false);
//        filter.setStatementPrepareAfterLogEnabled(false);
        return  filter;
    }
}

单数据源时：

@Slf4j
@ConditionalOnProperty(name = "spring.datasource.single", havingValue = "true", matchIfMissing = false)
@Configuration
public class DruidConfiguration {
    @Autowired
    private DruidSingleDatasourceProperties druidSingleDatasourceProperties;

    @Value("${spring.datasource.druid.filters:stat,wall,logback}")
    private String filters;

    @Value("${spring.datasource.druid.filter.stat.log-slow-sql:true}")
    private boolean logslowSql;
    @Value("${spring.datasource.druid.filter.stat.merge-sql:true}")
    private boolean mergeSql;
    @Value("${spring.datasource.druid.filter.stat.slow-sql-millis:200}")
    private long slowSqlMill;
//    @Value("${spring.datasource.connectionProperties}")
//    private String connectionProperties;
//    @Value("${spring.datasource.useGlobalDataSourceStat}")
//    private boolean useGlobalDataSourceStat;

    @Bean     //声明其为Bean实例
    @ConditionalOnProperty(name = "spring.datasource.druid.type", havingValue = "com.alibaba.druid.pool.DruidDataSource",
            matchIfMissing = true)
    @Primary  //在同样的DataSource中，首先使用被标注的DataSource
    public DataSource dataSource(){
        log.info("------------注册DruidDatasource-----------");

        DruidDataSource datasource = (DruidDataSource) druidSingleDatasourceProperties.initializeDataSourceBuilder().build();

        //        datasource.setUseGlobalDataSourceStat(useGlobalDataSourceStat);
        log.info("------------注册Druid过滤器-----------");
        try {
            datasource.setFilters(filters);
        } catch (SQLException e) {
            log.error("druid configuration initialization filter: "+ e);
        }
        datasource.setProxyFilters(Arrays.asList(statFilter(),logFilter()));
        log.info("------------注册Druid过滤器结束-----------");
        log.info("------------注册DruidDatasource结束-----------");
        return datasource;
    }

    @Bean
    @Primary
    public StatFilter statFilter(){
        StatFilter statFilter = new StatFilter();
        statFilter.setSlowSqlMillis(slowSqlMill);
        statFilter.setLogSlowSql(logslowSql);
        statFilter.setMergeSql(mergeSql);
        return statFilter;
    }

    @Bean
    public Slf4jLogFilter logFilter(){
        Slf4jLogFilter filter = new Slf4jLogFilter();
//        filter.setResultSetLogEnabled(false);
//        filter.setConnectionLogEnabled(false);
//        filter.setStatementParameterClearLogEnable(false);
//        filter.setStatementCreateAfterLogEnabled(false);
//        filter.setStatementCloseAfterLogEnabled(false);
//        filter.setStatementParameterSetLogEnabled(false);
//        filter.setStatementPrepareAfterLogEnabled(false);
        return  filter;
    }

}