Spring-MVC 中的 Bean 创建异常

Question

这是我的代码和我得到的异常，早些时候这个项目工作正常但是当我在其中添加 MySQL 连接和 Bean class 时，我得到了异常。

Jul 03, 2017 12:54:40 AM org.springframework.web.servlet.DispatcherServlet initServletBean
SEVERE: Context initialization failed
org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'defaultController': Injection of autowired dependencies failed; nested exception is org.springframework.beans.factory.BeanCreationException: Could not autowire field: metalist.yashdeep.scrap.service.IStockDetailsService metalist.yashdeep.scrap.controller.DefaultController.iStockDetailsService; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'iStockDetailsService': Injection of autowired dependencies failed; nested exception is org.springframework.beans.factory.BeanCreationException: Could not autowire field: metalist.yashdeep.scrap.dao.IStockDetailsDAO metalist.yashdeep.scrap.service.StockDetailsService.iStockDetailsDAO; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'stockDetailsDAO': Injection of autowired dependencies failed; nested exception is org.springframework.beans.factory.BeanCreationException: Could not autowire field: metalist.yashdeep.scrap.resource.DatabaseConnection metalist.yashdeep.scrap.dao.StockDetailsDAO.databaseConnection; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type [metalist.yashdeep.scrap.resource.DatabaseConnection] 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:292)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1185)
    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:304)
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:228)
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:300)
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:195)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:703)
    at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:760)
    at org.springframework.context.support.AbstractApplicationContext.__refresh(AbstractApplicationContext.java:482)
    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java)
    at org.springframework.web.servlet.FrameworkServlet.configureAndRefreshWebApplicationContext(FrameworkServlet.java:658)
    at org.springframework.web.servlet.FrameworkServlet.createWebApplicationContext(FrameworkServlet.java:624)
    at org.springframework.web.servlet.FrameworkServlet.createWebApplicationContext(FrameworkServlet.java:672)
    at org.springframework.web.servlet.FrameworkServlet.initWebApplicationContext(FrameworkServlet.java:543)
    at org.springframework.web.servlet.FrameworkServlet.initServletBean(FrameworkServlet.java:484)
    at org.springframework.web.servlet.HttpServletBean.init(HttpServletBean.java:136)
    at javax.servlet.GenericServlet.init(GenericServlet.java:158)
    at org.apache.catalina.core.StandardWrapper.initServlet(StandardWrapper.java:1269)
    at org.apache.catalina.core.StandardWrapper.loadServlet(StandardWrapper.java:1182)
    at org.apache.catalina.core.StandardWrapper.load(StandardWrapper.java:1072)
    at org.apache.catalina.core.StandardContext.loadOnStartup(StandardContext.java:5368)
    at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5660)
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:145)
    at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1571)
    at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1561)
    at java.util.concurrent.FutureTask.run(FutureTask.java:266)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
    at java.lang.Thread.run(Thread.java:745)

pom.xml

<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>MetalistEnterprises</groupId>
    <artifactId>MetalistEnterprises</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>war</packaging>
    <build>
        <sourceDirectory>src</sourceDirectory>
        <plugins>
            <plugin>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>3.5.1</version>
                <configuration>
                    <source>1.8</source>
                    <target>1.8</target>
                </configuration>
            </plugin>
            <plugin>
                <artifactId>maven-war-plugin</artifactId>
                <version>3.0.0</version>
                <configuration>
                    <warSourceDirectory>WebContent</warSourceDirectory>
                </configuration>
            </plugin>
        </plugins>
    </build>
    <properties>
        <spring.version>4.0.3.RELEASE</spring.version>
    </properties>
    <dependencies>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-webmvc</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-tx</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-core</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-web</artifactId>
            <version>${spring.version}</version>
            <type>jar</type>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-beans</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-framework-bom</artifactId>
            <version>${spring.version}</version>
            <type>pom</type>
            <scope>import</scope>
        </dependency>
        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>jstl</artifactId>
            <version>1.2</version>
        </dependency>
    </dependencies>
</project>

web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" id="WebApp_ID" version="3.0">
  <display-name>MetalistEnterprises</display-name>
    <servlet>
    <servlet-name>mvc-dispatcher</servlet-name>
    <servlet-class>
         org.springframework.web.servlet.DispatcherServlet
      </servlet-class>
    <load-on-startup>1</load-on-startup>
  </servlet>
  <servlet-mapping>
    <servlet-name>mvc-dispatcher</servlet-name>
    <url-pattern>/</url-pattern>
  </servlet-mapping>
</web-app>

控制器

@Controller
public class DefaultController {

    @Autowired
    IStockDetailsService iStockDetailsService;

    @RequestMapping(value = "/stock")
    public ModelAndView stockMethod(Model model) {
    ArrayList<StockBean> stocksList = iStockDetailsService.getAllStocks();
    model.addAttribute("stocksList", stocksList);
    return new ModelAndView("stock");
}

服务

@Service("iStockDetailsService")
public class StockDetailsService implements IStockDetailsService {

    @Autowired
    IStockDetailsDAO iStockDetailsDAO;

    @Override
    public ArrayList<StockBean> getAllStocks() {
        System.out.println("In Service, getAllStocks methods");
        ArrayList<StockBean> stocksList = iStockDetailsDAO.getAllStocks();
        return stocksList;
    }

豆子

public class StockBean {

    private Integer idStock;
    private String invoiceNumber;
    private Date invoiceDate;
    private String companyName;
    private String materialDescription;
    private float rate;
    private float amount;
    private float tax;

Getter and Settters
}

mvc-调度程序-servlet.xml

<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:context="http://www.springframework.org/schema/context"
    xmlns:mvc="http://www.springframework.org/schema/mvc" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns:jee="http://www.springframework.org/schema/jee"
    xsi:schemaLocation="
        http://www.springframework.org/schema/beans 
 http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
        http://www.springframework.org/schema/context 
        http://www.springframework.org/schema/context/spring-context-3.0.xsd
        http://www.springframework.org/schema/mvc 
        http://www.springframework.org/schema/mvc/spring-mvc-3.0.xsd
        http://www.springframework.org/schema/jee 
         http://www.springframework.org/schema/jee/spring-jee-3.0.xsd">

    <context:component-scan base-package="metalist.yashdeep.scrap" />
    <context:annotation-config />
    <mvc:resources mapping="/resource/**" location="/resource/" />
    <mvc:annotation-driven />

    <bean id="viewResolver"
        class="org.springframework.web.servlet.view.InternalResourceViewResolver">
        <property name="prefix">
            <value>/WEB-INF/view/</value>
        </property>
        <property name="suffix">
            <value>.jsp</value>
        </property>
    </bean>
</beans>

IStockDetailsDAO

import java.util.ArrayList;
import metalist.yashdeep.scrap.model.StockBean;
public interface IStockDetailsDAO {
    public ArrayList<StockBean> getAllStocks();
}

StockDetailsDAO

@Repository
public class StockDetailsDAO implements IStockDetailsDAO {

    @Autowired
    DatabaseConnection databaseConnection;

    @Autowired
    DatabaseQuery databaseQuery;

    @Override
    public ArrayList<StockBean> getAllStocks() {
        System.out.println("In DAO, getAllStocks methods");
        Connection conn = databaseConnection.getConnection();
        try {
            ArrayList<StockBean> arrayListStockBean = new ArrayList<StockBean>();
            String getAllQueries = databaseQuery.queryGetAllStocks;
            Statement stmt = conn.createStatement();
            ResultSet rs = stmt.executeQuery(getAllQueries);
            while (rs.next()) {
                StockBean stockBean = new StockBean();
                stockBean.setIdStock(rs.getInt("idStock"));
                stockBean.setInvoiceNumber(rs.getString("invoiceNumber"));
                stockBean.setInvoiceDate(rs.getDate("invoiceDate"));
                stockBean.setCompanyName(rs.getString("CompanyName"));              
          stockBean.setMaterialDescription(rs.getString("materialDescription"));
                stockBean.setRate(rs.getFloat("rate"));
                stockBean.setAmount(rs.getFloat("amount"));
                stockBean.setTax(rs.getFloat("tax"));
                arrayListStockBean.add(stockBean);
            }
            return arrayListStockBean;
        } catch (Exception ex) {
            return null;
        } finally {
            try {
                conn.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
    }
}

数据库连接

    package metalist.yashdeep.scrap.resource;

import java.sql.Connection;
import java.sql.DriverManager;

public class DatabaseConnection {

    public Connection getConnection() {
        System.out.println("In getConnection");
        try {
            System.out.println("Trying for Connection For NEOs");
            Class.forName("com.mysql.jdbc.Driver");
            Connection conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/metalistenterpriseschema",
                    "root", "root");
            System.out.println("Connection Successful For NEOs");
            return conn;
        } catch (Exception e) {
            System.out.println("Exception in getConnection. Exception is : " + e);
            return null;
        }

    }

}

Answer 1

您可能没有用 @Component 注释 metalist.yashdeep.scrap.resource.DatabaseConnection class，所以 spring 容器没有识别您的依赖 class

Spring-MVC 中的 Bean 创建异常

Bean Creation Exception in Spring-MVC

java

spring

spring-mvc

javabeans

beancreationexception