java 无法自动装配 - org.springframework.beans.factory.BeanCreationException
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时间：2020-11-02 09:24:50 来源:igfitidea点击:
Could not autowire - org.springframework.beans.factory.BeanCreationException
提问by memo
I am trying to build a restful web service with Spring Boot, Maven, and Tomcat.
我正在尝试使用 Spring Boot、Maven 和 Tomcat 构建一个安静的 Web 服务。
When I try to deploy maven jar file to Tomcat I receive this error:
当我尝试将 Maven jar 文件部署到 Tomcat 时，我收到此错误：
org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'selectConfRoomController': Injection of autowired dependencies failed; nested exception is org.springframework.beans.factory.BeanCreationException: Could not autowire field: private org.springframework.jdbc.core.JdbcTemplate hello.SelectConfRoomController.jt; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type [org.springframework.jdbc.core.JdbcTemplate] found for dependency: expected at least 1 bean which qualifies as autowire candidate for this dependency. Dependency annotations: {@org.springframework.beans.factory.annotation.Autowired(required=true)}
at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:293)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1186)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:537)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:475)
at org.springframework.beans.factory.support.AbstractBeanFactory.getObject(AbstractBeanFactory.java:302)
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:228)
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:298)
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:193)
at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:706)
at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:762)
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:482)
at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.refresh(EmbeddedWebApplicationContext.java:109)
at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:691)
at org.springframework.boot.SpringApplication.run(SpringApplication.java:320)
at org.springframework.boot.SpringApplication.run(SpringApplication.java:952)
at org.springframework.boot.SpringApplication.run(SpringApplication.java:941)
at hello.Application.main(Application.java:14)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at org.springframework.boot.loader.MainMethodRunner.run(MainMethodRunner.java:53)
at java.lang.Thread.run(Unknown Source)
Caused by: org.springframework.beans.factory.BeanCreationException: Could not autowire field: private org.springframework.jdbc.core.JdbcTemplate hello.SelectConfRoomController.jt; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type [org.springframework.jdbc.core.JdbcTemplate] found for dependency: expected at least 1 bean which qualifies as autowire candidate for this dependency. Dependency annotations: {@org.springframework.beans.factory.annotation.Autowired(required=true)}
at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:509)
at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:87)
at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:290)
... 22 common frames omitted
Caused by: org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type [org.springframework.jdbc.core.JdbcTemplate] found for dependency: expected at least 1 bean which qualifies as autowire candidate for this dependency. Dependency annotations: {@org.springframework.beans.factory.annotation.Autowired(required=true)}
at org.springframework.beans.factory.support.DefaultListableBeanFactory.raiseNoSuchBeanDefinitionException(DefaultListableBeanFactory.java:1118)
at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:967)
at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:862)
at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:481)
... 24 common frames omitted
My application.properties file is in package src/main/resources
我的 application.properties 文件在包 src/main/resources 中
spring.datasource.url=jdbc:jtds:sqlserver://***
spring.datasource.username=***
spring.datasource.password=***
spring.datasource.driverClassName=net.sourceforge.jtds.jdbc.Driver
src/main/java
源代码/主/Java
Application.java
应用程序.java
package hello;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
@Configuration
@ComponentScan
@EnableAutoConfiguration
public class Application {
public static void main(String[] args) {
SpringApplication.run(Application.class, args);
}
}
Querying...
查询...
package hello;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.List;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.jdbc.core.RowMapper;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RestController;
@RestController
public class SelectConfRoomController extends JdbcTemplate{
@Autowired
private JdbcTemplate jt;
@RequestMapping(value="/", method=RequestMethod.GET)
public List<Region> getRegions(){
String sql = "SELECT OUID_Region, RegionName FROM Region";
List <Region> rows = jt.query(sql,
new RowMapper<Region>(){
@Override
public Region mapRow(ResultSet rs, int rowNum) throws SQLException {
return new Region(rs.getLong("OUID_Region"), rs.getString("RegionName"));
}
});
System.out.println("querying regions");
return rows;
}
}
pom.xml
pom.xml
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>***</groupId>
<artifactId>webservice-test</artifactId>
<version>1</version>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>1.1.7.RELEASE</version>
</parent>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-jdbc</artifactId>
</dependency>
</dependencies>
<properties>
<start-class>hello.Application</start-class>
<java.version>1.8</java.version>
</properties>
<build>
<finalName>ConfRoom</finalName>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
<repositories>
<repository>
<id>spring-releases</id>
<url>http://repo.spring.io/libs-release</url>
</repository>
</repositories>
<pluginRepositories>
<pluginRepository>
<id>spring-releases</id>
<url>http://repo.spring.io/libs-release</url>
</pluginRepository>
</pluginRepositories>
</project>
Reading the solutions in this, I'm under the impression that I would not need an xml file. Can someone find an error that I'm not aware of? I am very new to all this so any expertise/guidance would be appreciated.
在读解这个，我的印象是，我不需要一个XML文件。有人能找到我不知道的错误吗？我对这一切都很陌生，因此任何专业知识/指导都将不胜感激。
回答by dunni
I think, the problem is, that you extend the JdbcTemplate. Spring Boot only creates a JdbcTemplate, if no other bean with this type is found. But your class is a bean of type JdbcTemplate, so the autoconfiguration for the JdbcTemplate is skipped. Try to remove the "extends JdbcTemplate", it doesn't seem to be required for your class.
我认为，问题是，您扩展了 JdbcTemplate。Spring Boot 仅创建一个 JdbcTemplate，如果没有找到其他具有此类型的 bean。但是您的类是 JdbcTemplate 类型的 bean，因此跳过了 JdbcTemplate 的自动配置。尝试删除“扩展 JdbcTemplate”，您的课程似乎不需要它。
回答by br1337
Try declaring a bean with JdbcTemplate
尝试声明一个 bean JdbcTemplate
@Bean
public DataSource getDataSource(){
/* Return the data source with proper configuration... */
}
@Autowired
public DataSource dataSource;
@Bean
public JdcTemplate getJdbcTemplate(){
JdbcTemplate jdbcTemplate = new JdbcTemplate(dataSource);
return dataSource;
}
回答by Hari
You need to specify the JDBCTemplate in context xml like below or you need to add the package for component scan.
您需要在上下文 xml 中指定 JDBCTemplate，如下所示，或者您需要添加用于组件扫描的包。
<bean id="jtDataSource"
class="org.springframework.jdbc.datasource.DriverManagerDataSource">
<property name="driverClassName" value="*******"/>
<property name="url" value="*******"/>
<property name="username" value="*****"/>
<property name="password" value="**********"/>
</bean>
<bean id="jt" class="org.springframework.jdbc.core.JdbcTemplate">
<property name="dataSource" ref="jtDataSource"/> --Incase if you are configuring data source
</bean>
