Java spring-boot 属性注入在自定义 @Configuration 类中不起作用
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spring-boot property injection not working in custom @Configuration class
提问by Dodge
I wanted to make a DatabaseConfig class to setup my database related stuff (EntityManager, DataSource, TransactionManager) and to get the properties I use @Value("${property.name}")on Stringfields
我想创建一个 DatabaseConfig 类来设置我的数据库相关内容（EntityManager、DataSource、TransactionManager）并获取我@Value("${property.name}")在String字段上使用的属性
like
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@Configuration
public class DataBaseConfig {
@Value("${hibernate.connection.username}")
private String hibernateConnectionUsername;
@Value("${hibernate.connection.password}")
private String hibernateConnectionPassword;
@Value("${hibernate.connection.driver_class}")
private String hibernateConnectionDriverClass;
@Value("${hibernate.connection.url}")
private String hibernateConnectionUrl;
@Value("${hibernate.dialect}")
private String hibernateDialect;
@Value("${hibernate.showSql}")
private String hibernateShowSql;
@Value("${hibernate.generateDdl}")
private String hibernateGenerateDdl;
// All my @Beans
}
The Problem is, that all those Strings are NULL instead of the values of my properties file.
问题是，所有这些字符串都是 NULL 而不是我的属性文件的值。
if I put the code into my Applicationclass (the one that has the mainand is referenced in SpringApplication.run(Application.class, args);) the value injection works
如果我将代码放入我的Application类（具有main和 中引用的类SpringApplication.run(Application.class, args);），则值注入有效
In short, @Value works in my Application class, but not in my custom @Configuration classes :(
简而言之，@Value 适用于我的 Application 类，但不适用于我的自定义 @Configuration 类:(
What could be wrong? Or are more informations needed?
可能有什么问题？还是需要更多信息？
UPDATE: More code
更新：更多代码
Way 1, DB Config and @Value in my Application.java works with and without the PropertySourcesPlaceholderConfigurer
方式 1，我的 Application.java 中的 DB Config 和 @Value 使用和不使用 PropertySourcesPlaceholderConfigurer
import java.beans.PropertyVetoException;
import javax.persistence.EntityManagerFactory;
import javax.sql.DataSource;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
import org.springframework.boot.autoconfigure.orm.jpa.HibernateJpaAutoConfiguration;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.data.jpa.repository.config.EnableJpaRepositories;
import org.springframework.orm.jpa.JpaTransactionManager;
import org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean;
import org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter;
import org.springframework.transaction.PlatformTransactionManager;
import com.mchange.v2.c3p0.ComboPooledDataSource;
@Configuration
@ComponentScan
@EnableJpaRepositories
@EnableAutoConfiguration(exclude = HibernateJpaAutoConfiguration.class)
public class Application {
public static void main(String[] args) throws Throwable {
SpringApplication.run(Application.class, args);
}
// @Bean
// public static PropertySourcesPlaceholderConfigurer properties() {
// PropertySourcesPlaceholderConfigurer pspc = new PropertySourcesPlaceholderConfigurer();
// pspc.setLocations(new Resource[] { new ClassPathResource("application.properties") });
// return pspc;
// }
/*****************************/
@Value("${hibernate.connection.username}")
private String hibernateConnectionUsername;
@Value("${hibernate.connection.password}")
private String hibernateConnectionPassword;
@Value("${hibernate.connection.driver_class}")
private String hibernateConnectionDriverClass;
@Value("${hibernate.connection.url}")
private String hibernateConnectionUrl;
@Value("${hibernate.dialect}")
private String hibernateDialect;
@Value("${hibernate.showSql}")
private String hibernateShowSql;
@Value("${hibernate.generateDdl}")
private String hibernateGenerateDdl;
@Bean
public LocalContainerEntityManagerFactoryBean entityManagerFactory() {
HibernateJpaVendorAdapter vendorAdapter = new HibernateJpaVendorAdapter();
vendorAdapter.setDatabasePlatform(hibernateDialect);
boolean generateDdl = Boolean.parseBoolean(hibernateGenerateDdl);
boolean showSql = Boolean.parseBoolean(hibernateShowSql);
vendorAdapter.setGenerateDdl(generateDdl);
vendorAdapter.setShowSql(showSql);
LocalContainerEntityManagerFactoryBean factory = new LocalContainerEntityManagerFactoryBean();
factory.setJpaVendorAdapter(vendorAdapter);
factory.setDataSource(dataSource());
factory.setPackagesToScan("xxx");
return factory;
}
@Bean
public DataSource dataSource() {
ComboPooledDataSource dataSource = new ComboPooledDataSource();
dataSource.setUser(hibernateConnectionUsername);
dataSource.setPassword(hibernateConnectionPassword);
try {
dataSource.setDriverClass(hibernateConnectionDriverClass);
} catch (PropertyVetoException e) {
throw new IllegalArgumentException("Wrong driver class");
}
dataSource.setJdbcUrl(hibernateConnectionUrl);
return dataSource;
}
@Bean
public PlatformTransactionManager transactionManager(EntityManagerFactory entityManagerFactory) {
return new JpaTransactionManager(entityManagerFactory);
}
}
Way 2 (what i want to have), DB Stuff in its own file (DatabaseConfing.java) does not work regardles of where i have the PropertySourcesPlaceholderConfigurer(Application or DatabaseConfig) as it is always called AFTER the @Beans inside the DatabaseConfig :(
方式 2（我想要的），DB Stuff 在它自己的文件（DatabaseConfing.java）中不起作用，不管我在哪里拥有PropertySourcesPlaceholderConfigurer（Application 或 DatabaseConfig），因为它总是在 DatabaseConfig 中的 @Beans 之后被调用:(
import java.beans.PropertyVetoException;
import java.util.ArrayList;
import java.util.List;
import javax.sql.DataSource;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.beans.factory.config.BeanDefinition;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ClassPathScanningCandidateComponentProvider;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.support.PropertySourcesPlaceholderConfigurer;
import org.springframework.core.io.ClassPathResource;
import org.springframework.core.io.Resource;
import org.springframework.core.type.filter.AnnotationTypeFilter;
import org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean;
import org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter;
import com.mchange.v2.c3p0.ComboPooledDataSource;
@Configuration
public class DatabaseConfig {
@Value("${hibernate.connection.username}")
private String hibernateConnectionUsername;
@Value("${hibernate.connection.password}")
private String hibernateConnectionPassword;
@Value("${hibernate.connection.driver_class}")
private String hibernateConnectionDriverClass;
@Value("${hibernate.connection.url}")
private String hibernateConnectionUrl;
@Value("${hibernate.dialect")
private String hibernateDialect;
@Value("${hibernate.showSql}")
private String hibernateShowSql;
@Value("${hibernate.generateDdl}")
private String hibernateGenerateDdl;
// @Bean
// public static PropertySourcesPlaceholderConfigurer properties() {
// PropertySourcesPlaceholderConfigurer pspc = new PropertySourcesPlaceholderConfigurer();
// pspc.setLocations(new Resource[] { new ClassPathResource("application.properties") });
// return pspc;
// }
@Bean
public LocalContainerEntityManagerFactoryBean entityManagerFactory() {
HibernateJpaVendorAdapter vendorAdapter = new HibernateJpaVendorAdapter();
vendorAdapter.setDatabasePlatform(hibernateDialect);
boolean generateDdl = Boolean.parseBoolean(hibernateGenerateDdl);
boolean showSql = Boolean.parseBoolean(hibernateShowSql);
vendorAdapter.setGenerateDdl(generateDdl);
vendorAdapter.setShowSql(showSql);
LocalContainerEntityManagerFactoryBean factory = new LocalContainerEntityManagerFactoryBean();
factory.setJpaVendorAdapter(vendorAdapter);
factory.setDataSource(dataSource());
factory.setPackagesToScan("xxx");
return factory;
}
@Bean
public DataSource dataSource() {
ComboPooledDataSource dataSource = new ComboPooledDataSource();
dataSource.setUser(hibernateConnectionUsername);
dataSource.setPassword(hibernateConnectionPassword);
try {
dataSource.setDriverClass(hibernateConnectionDriverClass);
} catch (PropertyVetoException e) {
throw new IllegalArgumentException("Wrong driver class");
}
System.err.println(hibernateConnectionUrl);
dataSource.setJdbcUrl(hibernateConnectionUrl);
return dataSource;
}
}
采纳答案by M. Deinum
Instead of your DatabaseConfigadd the following application.propertiesto src/main/resources(and thus remove your DatabaseConfigclass)
而不是你的DatabaseConfig添加以下application.properties到src/main/resources（从而删除您的DatabaseConfig类）
#DataSource configuration
spring.datasource.driverClassName=<hibernateConnectionDriverClass>
spring.datasource.url=<hibernateConnectionUrl>
spring.datasource.username=<hibernateConnectionUsername>
spring.datasource.password=<hibernateConnectionPassword>
#JPA/HIbernate
spring.jpa.database-platform=<dialect-class>
spring.jpa.generate-ddl=<hibernateGenerateDdl>
spring.jpa.show-sql=<hibernateShowSql>
Replace the < placeholder >with the actual value and spring-boot will take care of this.
将< placeholder >替换为实际值，spring-boot 会处理这个问题。
Tip remove the C3P0 dependency as Spring will provide you (default) with the tomcat connection pool (which is newer and more activly maintained and despite the name is perfectly usable without/outside Tomcat).
提示删除 C3P0 依赖项，因为 Spring 将为您（默认）提供 tomcat 连接池（它更新且维护得更活跃，尽管该名称在没有 Tomcat 的情况下/在 Tomcat 之外也完全可用）。
回答by Dodge
@Import({ CacheConfig.class, DatabaseConfig.class })
@ComponentScan(excludeFilters = @Filter(Configuration.class))
did the trick.
成功了。
