springboot（2.0以上） --数据源切换时报错

佚名 6年前 (2018-06-03) Mysql 1921人围观抢沙发百度已收录

在进行数据源切换时spring.datasource.type类型根据源码所给的默认值修改后依然报错

先看源码：标色部分，就是springboot所给的数据源，正常来说只要在配置文件中修改type值就可以，但是我发现不行依然报错：

@ConditionalOnClass(org.apache.tomcat.jdbc.pool.DataSource.class)
    @ConditionalOnProperty(name = "spring.datasource.type", havingValue = "org.apache.tomcat.jdbc.pool.DataSource", matchIfMissing = true) static class Tomcat extends DataSourceConfiguration {

        @Bean
        @ConfigurationProperties(prefix = "spring.datasource.tomcat")
        public org.apache.tomcat.jdbc.pool.DataSource dataSource(
                DataSourceProperties properties) {
            org.apache.tomcat.jdbc.pool.DataSource dataSource = createDataSource(
                    properties, org.apache.tomcat.jdbc.pool.DataSource.class);
            DatabaseDriver databaseDriver = DatabaseDriver
                    .fromJdbcUrl(properties.determineUrl());
            String validationQuery = databaseDriver.getValidationQuery();
            if (validationQuery != null) {
                dataSource.setTestOnBorrow(true);
                dataSource.setValidationQuery(validationQuery);
            }
            return dataSource;
        }

    }

    /**
     * Hikari DataSource configuration.
     */
    @ConditionalOnClass(HikariDataSource.class)
    @ConditionalOnProperty(name = "spring.datasource.type", havingValue = "com.zaxxer.hikari.HikariDataSource", matchIfMissing = true) static class Hikari extends DataSourceConfiguration {

        @Bean
        @ConfigurationProperties(prefix = "spring.datasource.hikari")
        public HikariDataSource dataSource(DataSourceProperties properties) {
            HikariDataSource dataSource = createDataSource(properties,
                    HikariDataSource.class);
            if (StringUtils.hasText(properties.getName())) {
                dataSource.setPoolName(properties.getName());
            }
            return dataSource;
        }

    }

    /**
     * DBCP DataSource configuration.
     */
    @ConditionalOnClass(org.apache.commons.dbcp2.BasicDataSource.class)
    @ConditionalOnProperty(name = "spring.datasource.type", havingValue = "org.apache.commons.dbcp2.BasicDataSource", matchIfMissing = true) static class Dbcp2 extends DataSourceConfiguration {

        @Bean
        @ConfigurationProperties(prefix = "spring.datasource.dbcp2")
        public org.apache.commons.dbcp2.BasicDataSource dataSource(
                DataSourceProperties properties) {
            return createDataSource(properties,
                    org.apache.commons.dbcp2.BasicDataSource.class);
        }

    }

错误信息：这个错好多人给出的答案是让编辑器自动提示而不自己写就不会出现（显然不行的），value值是springboot源码上自带的，因此也不会错，但是为什么会报错呢？

Description:

Failed to bind properties under 'spring.datasource.type' to java.lang.Class<javax.sql.DataSource>:

    Property: spring.datasource.type
    Value: org.apache.commons.dbcp2.BasicDataSource
    Origin: class path resource [application.yml]:7:11
    Reason: No converter found capable of converting from type [java.lang.String] to type [java.lang.Class<javax.sql.DataSource>]

Action:

Update your application's configuration

原因：

在导入druid数据源时，也就是外部数据源，我们必须导入相关依赖，因此我尝试将springboot默认数据源的相关依赖也导入

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引入（maven）：

<!-- https://mvnrepository.com/artifact/org.apache.commons/commons-dbcp2 -->
<dependency>
    <groupId>org.apache.commons</groupId>
    <artifactId>commons-dbcp2</artifactId>
    <version>2.2.0</version>
</dependency>