沒有可用的'xxx.dao.AreaDao'類型的合格Bean：預計至少有1個符合自動裝配候選條件的Bean

Question

我正在學習Maven，但運行此錯誤：

沒有可用的'com.yxnh.o2o.dao.AreaDao'類型的合格Bean：預期至少有1個有資格作為自動裝配候選者的Bean。 依賴項注釋：{@ org.springframework.beans.factory.annotation.Autowired（required = true）}

我已經嘗試了所有四種在線方式，關於配置文件“ spring-dao.xml”，單詞拼寫錯誤，注釋，但是它們都不能解決我的問題。

我先顯示我的問題

……
……
16:24:23.125 [main] DEBUG org.springframework.beans.factory.support.DefaultListableBeanFactory - Creating shared instance of singleton bean 'org.springframework.context.annotation.internalAutowiredAnnotationProcessor'
16:24:23.126 [main] DEBUG org.springframework.beans.factory.support.DefaultListableBeanFactory - Creating shared instance of singleton bean 'org.springframework.context.annotation.internalCommonAnnotationProcessor'
16:24:23.141 [main] DEBUG org.springframework.test.context.cache.DefaultCacheAwareContextLoaderDelegate - Storing ApplicationContext in cache under key [[MergedContextConfiguration@3a883ce7 testClass = AreaDaoTest, locations = '{classpath:*/spring/spring-dao.xml}', classes = '{}', contextInitializerClasses = '[]', activeProfiles = '{}', propertySourceLocations = '{}', propertySourceProperties = '{}', contextCustomizers = set[[empty]], contextLoader = 'org.springframework.test.context.support.DelegatingSmartContextLoader', parent = [null]]]
16:24:23.141 [main] DEBUG org.springframework.test.context.cache - Spring test ApplicationContext cache statistics: [DefaultContextCache@657c8ad9 size = 1, maxSize = 32, parentContextCount = 0, hitCount = 0, missCount = 1]
16:24:23.150 [main] ERROR org.springframework.test.context.TestContextManager - Caught exception while allowing TestExecutionListener [org.springframework.test.context.support.DependencyInjectionTestExecutionListener@57536d79] to prepare test instance [com.yxnh.o2o.dao.AreaDaoTest@68bbe345]
org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'com.yxnh.o2o.dao.AreaDaoTest': Unsatisfied dependency expressed through field 'areaDao'; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type 'com.yxnh.o2o.dao.AreaDao' available: expected at least 1 bean which qualifies as autowire candidate. Dependency annotations: {@org.springframework.beans.factory.annotation.Autowired(required=true)}
    at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:596)
    at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:90)
    at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessProperties(AutowiredAnnotationBeanPostProcessor.java:374)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1411)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.autowireBeanProperties(AbstractAutowireCapableBeanFactory.java:391)
    at org.springframework.test.context.support.DependencyInjectionTestExecutionListener.injectDependencies(DependencyInjectionTestExecutionListener.java:119)
    at org.springframework.test.context.support.DependencyInjectionTestExecutionListener.prepareTestInstance(DependencyInjectionTestExecutionListener.java:83)
    at org.springframework.test.context.TestContextManager.prepareTestInstance(TestContextManager.java:246)
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.createTest(SpringJUnit4ClassRunner.java:227)
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner$1.runReflectiveCall(SpringJUnit4ClassRunner.java:289)
    at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.methodBlock(SpringJUnit4ClassRunner.java:291)
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:246)
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:97)
    at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
    at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
    at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
    at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
    at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
    at org.springframework.test.context.junit4.statements.RunBeforeTestClassCallbacks.evaluate(RunBeforeTestClassCallbacks.java:61)
    at org.springframework.test.context.junit4.statements.RunAfterTestClassCallbacks.evaluate(RunAfterTestClassCallbacks.java:70)
    at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.run(SpringJUnit4ClassRunner.java:190)
    at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:89)
    at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:41)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:541)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:763)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:463)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:209)
Caused by: org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type 'com.yxnh.o2o.dao.AreaDao' available: expected at least 1 bean which qualifies as autowire candidate. Dependency annotations: {@org.springframework.beans.factory.annotation.Autowired(required=true)}
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.raiseNoMatchingBeanFound(DefaultListableBeanFactory.java:1658)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1217)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1171)
    at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:593)
    ... 28 common frames omitted
16:24:23.155 [main] DEBUG org.springframework.test.context.support.AbstractDirtiesContextTestExecutionListener - After test class: context [DefaultTestContext@cd2dae5 testClass = AreaDaoTest, testInstance = [null], testMethod = [null], testException = [null], mergedContextConfiguration = [MergedContextConfiguration@3a883ce7 testClass = AreaDaoTest, locations = '{classpath:*/spring/spring-dao.xml}', classes = '{}', contextInitializerClasses = '[]', activeProfiles = '{}', propertySourceLocations = '{}', propertySourceProperties = '{}', contextCustomizers = set[[empty]], contextLoader = 'org.springframework.test.context.support.DelegatingSmartContextLoader', parent = [null]], attributes = map[[empty]]], class annotated with @DirtiesContext [false] with mode [null].
16:24:23.158 [Thread-0] DEBUG org.springframework.context.support.GenericApplicationContext - Closing org.springframework.context.support.GenericApplicationContext@59e5ddf, started on Tue Jul 23 16:24:23 CST 2019

spring-dao.xml

<context:property-placeholder
        location="classpath:jdbc.properties" />

    <!-- 2.數據庫連接池 -->
    <bean id="dataSource"
        class="com.mchange.v2.c3p0.ComboPooledDataSource">
        <!-- 配置連接池屬性 -->
        <property name="driverClass" value="${jdbc.driver}" />
        <property name="jdbcUrl" value="${jdbc.url}" />
        <property name="user" value="${jdbc.username}" />
        <property name="password" value="${jdbc.password}" />

        <!-- c3p0連接池的私有屬性 -->
        <property name="maxPoolSize" value="30" />
        <property name="minPoolSize" value="10" />
        <!-- 關閉連接后不自動commit -->
        <property name="autoCommitOnClose" value="false" />
        <!-- 獲取連接超時時間 -->
        <property name="checkoutTimeout" value="10000" />
        <!-- 當獲取連接失敗重試次數 -->
        <property name="acquireRetryAttempts" value="2" />
    </bean>

    <!-- 3.配置SqlSessionFactory對象 -->
    <bean id="sqlSessionFactory"
        class="org.mybatis.spring.SqlSessionFactoryBean">
        <!-- 注入數據庫連接池 -->
        <property name="dataSource" ref="dataSource" />
        <!-- 配置MyBaties全局配置文件:mybatis-config.xml -->
        <property name="configLocation"
            value="classpath:mybatis-config.xml" />
        <!-- 掃描entity包 使用別名 -->
        <property name="typeAliasesPackage"
            value="com.yxnh.o2o.entity" />
        <!-- 掃描sql配置文件:mapper需要的xml文件 -->
        <property name="mapperLocations"
            value="classpath:mapper/*.xml" />
    </bean>

    <!-- 4.配置掃描Dao接口包，動態實現Dao接口，注入到spring容器中 -->
    <bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
        <!-- 注入sqlSessionFactory -->
        <property name="sqlSessionFactoryBeanName"
            value="sqlSessionFactory" />
        <!-- 給出需要掃描Dao接口包 -->
        <property name="basePackage" value="com.yxnh.o2o.dao" />
    </bean>

BaseTest.java

package com.yxnh.o2o;

import org.junit.runner.RunWith;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;

/**
 * 配置spring和junit整合，junit啟動時加載springIOC容器
 * 
 * @author BCLZ-JG
 *
 */
@RunWith(SpringJUnit4ClassRunner.class)
//告訴junit spring配置文件的位置
@ContextConfiguration({"classpath*:spring/spring-dao.xml"})
public class BaseTest {

}

AreaDaoTest.java

package com.yxnh.o2o.dao;

import static org.junit.Assert.assertEquals;

import java.util.List;

import org.junit.Test;
import org.springframework.beans.factory.annotation.Autowired;

import com.yxnh.o2o.BaseTest;
import com.yxnh.o2o.dao.AreaDao;
import com.yxnh.o2o.entity.Area;

public class AreaDaoTest extends BaseTest {
    @Autowired
    private AreaDao areaDao;

    @Test
    public void testQueryArea() {
        List<Area> areaList = areaDao.queryArea();
        assertEquals(2, areaList.size());
    }
}

AreaDao.java

package com.yxnh.o2o.dao;

import java.util.List;

import com.yxnh.o2o.entity.Area;

public interface AreaDao {
    /**
     * 鍒楀嚭鍖哄煙鍒楄〃
     * 
     * @return
     */
    List<Area> queryArea();
}

非常抱歉，由於我的帳戶評分不足，我無法回復其他人的回答。 如果您問我，我會及時發表評論並回復。 再次感謝您的幫助。

Answer 1

我相信您需要為AreaAao接口添加一個實現，以便自動裝配能夠平穩運行。