创建我的第一个 spring mvc 项目时出错

【问题标题】：Errors creating my first spring mvc project创建我的第一个 spring mvc 项目时出错
【发布时间】：2017-08-11 07:05:23
【问题描述】：

我是 spring mvc 的新手，我正在关注一本名为 spring-mvc-beginners-guide 的书。但是项目中出现了一些错误，我无法继续。

This is a photo of the project structure

DispatcherServletInitializer.java

package com.packt.webstore.config;
@Configuration
@EnableWebMvc
@ComponentScan("com.packt.webstore")
public class WebApplicationContextConfig extends WebMvcConfigurerAdapter {
@Override
    public void configureDefaultServletHandling (DefaultServletHandlerConfigurer configurer) {
        configurer.enable();
    }
    @Bean
    public InternalResourceViewResolver getInternalResourceViewResolver() {
        InternalResourceViewResolver resolver = new
        InternalResourceViewResolver();
        resolver.setViewClass(JstlView.class);
        resolver.setPrefix("/WEB-INF/views/");
        resolver.setSuffix(".jsp");
        return resolver;
    }
}

RootApplicationContextConfig.java

package com.packt.webstore.config;

@Configuration
@ComponentScan("com.packt.webstore.controller")
public class RootApplicationContextConfig {
    @Bean
    public DataSource dataSource() {
        EmbeddedDatabaseBuilder builder = new EmbeddedDatabaseBuilder();
        EmbeddedDatabase db = builder.setType(EmbeddedDatabaseType.HSQL).addScript("db/sql/create-table.sql")
                .addScript("db/sql/insert-data.sql").build();
        return db;
    }

    @Bean
    public NamedParameterJdbcTemplate getJdbcTemplate() {
        return new NamedParameterJdbcTemplate(dataSource());
    }
}

WebApplicationContextConfig.java

package com.packt.webstore.config;

@Configuration
@EnableWebMvc
@ComponentScan("com.packt.webstore")
public class WebApplicationContextConfig extends WebMvcConfigurerAdapter {
@Override
    public void configureDefaultServletHandling (DefaultServletHandlerConfigurer configurer) {
        configurer.enable();
    }
    @Bean
    public InternalResourceViewResolver getInternalResourceViewResolver() {
        InternalResourceViewResolver resolver = new
        InternalResourceViewResolver();
        resolver.setViewClass(JstlView.class);
        resolver.setPrefix("/WEB-INF/views/");
        resolver.setSuffix(".jsp");
        return resolver;
    }
}

HomeController.java

package com.packt.webstore.controller;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.RequestMapping;
@Controller
public class HomeController {
    @RequestMapping("/")
    public String welcome(Model model) {
        model.addAttribute("greeting", "Welcome to Web Store!");
        model.addAttribute("tagline", "The one and only amazing web store");
        return "welcome";
    }
}

ProductController.java

package com.packt.webstore.controller;


@Controller
public class ProductController {

    @Autowired
    private ProductRepository productRepository;

    @RequestMapping("/products")
    public String list(Model model) {
        model.addAttribute("products", productRepository.getAllProducts());
        return "products";
    }
}

Product.java

package com.packt.webstore.domain;

import java.io.Serializable;
import java.math.BigDecimal;
public class Product implements Serializable {
    private static final long serialVersionUID = 3678107792576131001L;
    private String productId;
    private String name;
    private BigDecimal unitPrice;
    private String description;
    private String manufacturer;
    private String category;
    private long unitsInStock;
    private long unitsInOrder;
    private boolean discontinued;
    private String condition;

    public Product() {
        super();
    }
    public Product(String productId, String name, BigDecimal unitPrice) {
        this.productId = productId;
        this.name = name;
        this.unitPrice = unitPrice;
    }

    // Here i deleted getters and setter for compact code
    @Override
    public boolean equals(Object obj) {
    if (this == obj)
        return true;
    if (obj == null)
        return false;
    if (getClass() != obj.getClass())
        return false;
    Product other = (Product) obj;
    if (productId == null) {
        if (other.productId != null)
            return false;
    } else if (!productId.equals(other.productId))
        return false;
    return true;
    }

    @Override
    public int hashCode() {
        final int prime = 31;
        int result = 1;
        result = prime * result + ((productId == null) ? 0 : productId.hashCode());
        return result;
    }
}

ProductRepository.java

package com.packt.webstore.domain.repository;

@ComponentScan
public interface ProductRepository {
    List<Product> getAllProducts();
}

InMemoryProductRepository.java

package com.packt.webstore.domain.repository.impl;

@Repository
public class InMemoryProductRepository implements ProductRepository {
    @Autowired
    private NamedParameterJdbcTemplate jdbcTemplate;

    @Override
    public List<Product> getAllProducts() {
        Map<String, Object> params = new HashMap<String, Object>();
        List<Product> result = jdbcTemplate.query("SELECT * FROM products", params, new ProductMapper());
        return result;
    }

    private static final class ProductMapper implements RowMapper<Product> {
        public Product mapRow(ResultSet rs, int rowNum) throws SQLException {
            Product product = new Product();
            product.setProductId(rs.getString("ID"));
            product.setName(rs.getString("NAME"));
            product.setDescription(rs.getString("DESCRIPTION"));
            product.setUnitPrice(rs.getBigDecimal("UNIT_PRICE"));
            product.setManufacturer(rs.getString("MANUFACTURER"));
            product.setCategory(rs.getString("CATEGORY"));
            product.setCondition(rs.getString("CONDITION"));
            product.setUnitsInStock(rs.getLong("UNITS_IN_STOCK"));
            product.setUnitsInOrder(rs.getLong("UNITS_IN_ORDER"));
            product.setDiscontinued(rs.getBoolean("DISCONTINUED"));
            return product;
        }
    }
}

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">
  <build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-war-plugin</artifactId>
<version>2.6</version>
<configuration>
<failOnMissingWebXml>false</failOnMissingWebXml>
</configuration>
</plugin>
</plugins>
</build>
  <modelVersion>4.0.0</modelVersion>
  <groupId>com.packt</groupId>
  <artifactId>webstore</artifactId>
  <version>0.0.1-SNAPSHOT</version>
  <packaging>war</packaging>
  <properties>
    <maven.compiler.source>1.8</maven.compiler.source>
    <maven.compiler.target>1.8</maven.compiler.target>
  </properties>
  <dependencies>
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-webmvc</artifactId>
        <version>4.3.0.RELEASE</version>
    </dependency>
    <dependency>
        <groupId>javax.servlet</groupId>
        <artifactId>jstl</artifactId>
        <version>1.2</version>
    </dependency>
    <dependency>
        <groupId>javax.servlet</groupId>
        <artifactId>javax.servlet-api</artifactId>
        <version>3.1.0</version>
        <scope>provided</scope>
    </dependency>
    <dependency>
    <groupId>org.springframework.security</groupId>
    <artifactId>spring-security-web</artifactId>
    <version>4.0.3.RELEASE</version>
</dependency>
<dependency>
    <groupId>org.springframework.security</groupId>
    <artifactId>spring-security-config</artifactId>
    <version>4.0.3.RELEASE</version>
</dependency>
<dependency>
    <groupId>org.springframework.security</groupId>
    <artifactId>spring-security-ldap</artifactId>
    <version>4.0.3.RELEASE</version>
</dependency>
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-jdbc</artifactId>
        <version>4.3.0.RELEASE</version>
    </dependency>
    <dependency>
        <groupId>org.hsqldb</groupId>
        <artifactId>hsqldb</artifactId>
        <version>2.3.2</version>
    </dependency>
  </dependencies>
</project>

和堆栈跟踪

GRAVE: Context initialization failed
org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'productController': Unsatisfied dependency expressed through field 'productRepository': No qualifying bean of type [com.packt.webstore.domain.repository.ProductRepository] found for dependency [com.packt.webstore.domain.repository.ProductRepository]: expected at least 1 bean which qualifies as autowire candidate for this dependency. Dependency annotations: {@org.springframework.beans.factory.annotation.Autowired(required=true)}; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type [com.packt.webstore.domain.repository.ProductRepository] found for dependency [com.packt.webstore.domain.repository.ProductRepository]: 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:573)
    at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:88)
    at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:350)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1214)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:543)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:482)
    at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:306)
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230)
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:302)
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:197)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:775)
    at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:861)
    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:541)
    at org.springframework.web.context.ContextLoader.configureAndRefreshWebApplicationContext(ContextLoader.java:444)
    at org.springframework.web.context.ContextLoader.initWebApplicationContext(ContextLoader.java:326)
    at org.springframework.web.context.ContextLoaderListener.contextInitialized(ContextLoaderListener.java:107)
    at org.apache.catalina.core.StandardContext.listenerStart(StandardContext.java:4743)
    at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5207)
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
    at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1419)
    at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1409)
    at java.util.concurrent.FutureTask.run(Unknown Source)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
    at java.lang.Thread.run(Unknown Source)
Caused by: org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type [com.packt.webstore.domain.repository.ProductRepository] found for dependency [com.packt.webstore.domain.repository.ProductRepository]: 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:1398)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1051)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1018)
    at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:570)
    ... 24 more

ago 11, 2017 8:32:51 AM org.apache.catalina.core.StandardContext listenerStart
GRAVE: Excepción enviando evento inicializado de contexto a instancia de escuchador de clase [org.springframework.web.context.ContextLoaderListener]
org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'productController': Unsatisfied dependency expressed through field 'productRepository': No qualifying bean of type [com.packt.webstore.domain.repository.ProductRepository] found for dependency [com.packt.webstore.domain.repository.ProductRepository]: expected at least 1 bean which qualifies as autowire candidate for this dependency. Dependency annotations: {@org.springframework.beans.factory.annotation.Autowired(required=true)}; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type [com.packt.webstore.domain.repository.ProductRepository] found for dependency [com.packt.webstore.domain.repository.ProductRepository]: 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:573)
    at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:88)
    at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:350)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1214)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:543)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:482)
    at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:306)
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230)
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:302)
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:197)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:775)
    at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:861)
    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:541)
    at org.springframework.web.context.ContextLoader.configureAndRefreshWebApplicationContext(ContextLoader.java:444)
    at org.springframework.web.context.ContextLoader.initWebApplicationContext(ContextLoader.java:326)
    at org.springframework.web.context.ContextLoaderListener.contextInitialized(ContextLoaderListener.java:107)
    at org.apache.catalina.core.StandardContext.listenerStart(StandardContext.java:4743)
    at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5207)
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
    at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1419)
    at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1409)
    at java.util.concurrent.FutureTask.run(Unknown Source)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
    at java.lang.Thread.run(Unknown Source)
Caused by: org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type [com.packt.webstore.domain.repository.ProductRepository] found for dependency [com.packt.webstore.domain.repository.ProductRepository]: 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:1398)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1051)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1018)
    at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:570)
    ... 24 more

ago 11, 2017 8:32:51 AM org.apache.catalina.core.StandardContext startInternal
GRAVE: One or more listeners failed to start. Full details will be found in the appropriate container log file
ago 11, 2017 8:32:51 AM org.apache.catalina.core.StandardContext startInternal
GRAVE: Falló en arranque del Contexto [/webstore] debido a errores previos
ago 11, 2017 8:32:51 AM org.apache.catalina.core.ApplicationContext log
INFORMACIÓN: Closing Spring root WebApplicationContext
ago 11, 2017 8:32:51 AM org.apache.coyote.AbstractProtocol start
INFORMACIÓN: Starting ProtocolHandler ["http-nio-8080"]
ago 11, 2017 8:32:51 AM org.apache.coyote.AbstractProtocol start
INFORMACIÓN: Starting ProtocolHandler ["ajp-nio-8009"]
ago 11, 2017 8:32:51 AM org.apache.catalina.startup.Catalina start
INFORMACIÓN: Server startup in 2681 ms

PD：我删除了紧凑代码的导入。如果您需要它们或其他任何东西，请告诉我。提前致谢

【问题讨论】：

  • 删除@ComponentScan 那里不需要public interface ProductRepository
  • 谢谢，已经删除，但错误依旧
  • 您是否在控制器中导入了正确的ProductRepository？
  • 我想是的，我想，但我不确定。我在 ProductController 中有导入，但在 HomeController 中没有

标签： java spring spring-mvc


【解决方案1】：

更改 @ComponentScan("com.packt.webstore.controller") 以包含 InMemoryProductRepository 所在的包。

您的扫描无法找到存储库，因为它仅扫描控制器包。

【讨论】：

  • 我认为这是不正确的，因为如果我进行更改，您会告诉我堆栈跟踪中还有更多错误。在这里可以看到当前的stacktrace textuploader.com/doyl3
  • 这意味着你需要 HSQL DB 驱动依赖。一般来说，您无论如何都需要修复所有错误。
  • 但是我在 pom.xml 中有 HSQL 依赖项，并且我在 maven 的依赖项中添加了 hsqldb-2.3.2.jar。那我应该怎么做才能解决呢？
  • 我不知道到底出了什么问题。发布的代码看起来不错。检查war文件是否正确添加了jar。您可能需要另一个更详细的问题。我指出了如何解决原始问题，而不是代码中所有可能的错误：-)
【解决方案2】：

使用公共接口 ProductRepository 中的 @Component 替换 @ComponentScan

【讨论】：

  • 我已经尝试过了，但我得到了与问题中相同的错误。你能告诉我这种变化的原因吗？这么说还是用 ComponentScan
  • "@ComponentScan" 用于定义组件所在的包。和“@Component”用于将该类作为组件。
  • 你在公共类 RootApplicationContextConfig {} 中尝试过这个包路径“@ComponentScan("com.packt.webstore") 吗？
【解决方案3】：

我建议在学习 Spring Boot 时选择一种“正确的方式”。 使用“旧书”，您可能会获得错误的体验，因此会花费太多时间。 Spring 有自己非常有用的guides，可以帮助你快速上手。例如：

Serving Web Content with Spring MVC

Handling Form Submission

Accessing Data with JPA

您还可以使用 Spring MVC 和 Spring Data JPA 检查我的简单 example CRUD 应用程序。

【讨论】：

  • 谢谢 Cepr0，我要试试那些指南
  • @V.Vallejo 如果答案对您有帮助，请不要忘记接受/投票...）
【解决方案4】：

应该是：

@Component
public interface ProductRepository {
    List<Product> getAllProducts();
}

@ComponentScan 是不同的东西，它会扫描指定的包并在找到任何注解时创建 bean。

另外请参考1个好的答案here。

【讨论】：

  • 谢谢老哥，这种解释派上用场了，因为我还是从spring开始
  • 您好@V.Vallejo，如果您对任何答案感到满意，请接受。
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