java - SpringBoot创建DynamicDataSource : Requested bean is currently in creation: Is there an unresolvable circular reference?

Question

@Bean(name = "masterDataSource")
@Primary
@ConfigurationProperties(prefix="spring.datasource.master")
public DataSource masterDataSource() {
    DruidDataSource dataSource = new DruidDataSource();
    return dataSource;
}

@Bean(name = "slaveDataSource")
@ConfigurationProperties(prefix="spring.datasource.slave")
public DataSource slaveDataSource() {
    DruidDataSource dataSource = new DruidDataSource();
    return dataSource;
}

@Bean(name = "dynamicDataSource")
public DataSource dataSource(@Qualifier("masterDataSource") DataSource masterDataSource,
                             @Qualifier("slaveDataSource") DataSource slaveDataSource) {
    DynamicDataSource dynamicDataSource = new DynamicDataSource();
    Map<Object, Object> dataSourceMap = new HashMap<>();
    dataSourceMap.put("masterDataSource", masterDataSource);
    dataSourceMap.put("slaveDataSource", slaveDataSource);
    dynamicDataSource.setTargetDataSources(dataSourceMap);
    dynamicDataSource.setDefaultTargetDataSource(masterDataSource);
    return dynamicDataSource;
}

这是我创建动态数据源的代码，但似乎有问题

Error creating bean with name 'dynamicDataSource': Requested bean is currently in creation: Is there an unresolvable circular reference? 

是否存在无法解析的循环引用？我该如何修复它？

感谢您的回答!

Answer 1

在您的情况下，dynamicDataSource 创建依赖于其他 2 个 bean slaveDataSource 和 masterDataSource。因此，您需要在 bean dynamicDataSource 上添加 @DependsOn，它指示 Spring bean dynamicDataSource 的创建也依赖于其他 2 个 bean。

因此您更新后的配置应如下所示:

@DependsOn({"masterDataSource", "slaveDataSource"})
@Bean(name = "dynamicDataSource")
public DataSource dataSource(@Autowired @Qualifier("masterDataSource") DataSource masterDataSource, @Autowired @Qualifier("slaveDataSource") DataSource slaveDataSource) {
    DynamicDataSource dynamicDataSource = new DynamicDataSource();
    Map<Object, Object> dataSourceMap = new HashMap<>();
    dataSourceMap.put("masterDataSource", masterDataSource);
    dataSourceMap.put("slaveDataSource", slaveDataSource);
    dynamicDataSource.setTargetDataSources(dataSourceMap);
    dynamicDataSource.setDefaultTargetDataSource(masterDataSource);
    return dynamicDataSource;
}

已更新

根据Spring Documentation ,

Beans on which the current bean depends. Any beans specified are guaranteed to be created by the container before this bean. Used infrequently in cases where a bean does not explicitly depend on another through properties or constructor arguments, but rather depends on the side effects of another bean's initialization.

或者了解更多信息，请查看此 Why @DependsOn has no effect