Spitter 不满足依赖异常 Spring MVC

Question

我从 Spring MVC 开始，阅读 Spring in Action 一书，我正在使用 Spitter 应用程序进行第 5 章的练习，但出现以下错误：

org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'spittleController' defined in file [C:\xampp\htdocs.metadata.plugins\org.eclipse.wst.server.core\tmp1\wtpwebapps\spitter\WEB-INF\classes\com\spitter\web\SpittleController.class]: Unsatisfied dependency expressed through constructor argument with index 0 of type [com.spitter.data.SpittleRepository]: : No qualifying bean of type [com.spitter.data.SpittleRepository] found for dependency: expected at least 1 bean which qualifies as autowire candidate for this dependency. Dependency annotations: {}; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type [com.spitter.data.SpittleRepository] found for dependency: expected at least 1 bean which qualifies as autowire candidate for this dependency. Dependency annotations: {}

我在github这里得到了这个项目：https://github.com/kevingcfcb88/spitter.git

我已经做了研究，但似乎没有任何效果。

我正在使用 STS 和 Maven，这是应用程序的结构：

这是我的 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>com.spitter.config</groupId>
<artifactId>spitter</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>war</packaging>

<name>spitter</name>
<url>http://maven.apache.org</url>

<properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    <springframework.version>4.1.5.RELEASE</springframework.version>
</properties>

<dependencies>
    <dependency>
        <groupId>junit</groupId>
        <artifactId>junit</artifactId>
        <version>3.8.1</version>
        <scope>test</scope>
    </dependency>
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-webmvc</artifactId>
        <version>${springframework.version}</version>
    </dependency>
    <dependency>
        <groupId>javax.servlet</groupId>
        <artifactId>javax.servlet-api</artifactId>
        <version>3.1.0</version>
    </dependency>
    <dependency>
        <groupId>javax.servlet.jsp</groupId>
        <artifactId>javax.servlet.jsp-api</artifactId>          
        <version>2.3.1</version>
    </dependency>
    <dependency>
        <groupId>javax.servlet</groupId>
        <artifactId>jstl</artifactId>
        <version>1.2</version>
    </dependency>
    <!-- https://mvnrepository.com/artifact/org.apache.commons/commons-lang3 -->
    <dependency>
        <groupId>org.apache.commons</groupId>
        <artifactId>commons-lang3</artifactId>
        <version>3.0</version>
    </dependency>

</dependencies>

<build>
    <pluginManagement>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>3.2</version>
                <configuration>
                    <source>1.8</source>
                    <target>1.8</target>
                </configuration>
            </plugin>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-war-plugin</artifactId>
                <version>2.4</version>
                <configuration>
                    <warSourceDirectory>src/main/webapp</warSourceDirectory>
                    <warName>spitter</warName>
                    <failOnMissingWebXml>false</failOnMissingWebXml>
                </configuration>
            </plugin>
        </plugins>
    </pluginManagement>
    <finalName>spitter</finalName>
</build>

还有我的配置文件：

SpittrWebAppInitializer.java

 package com.spitter.config;

import org.springframework.web.servlet.support.AbstractAnnotationConfigDispatcherServletInitializer;

public class SpittrWebAppInitializer extends AbstractAnnotationConfigDispatcherServletInitializer{

    @Override
    protected Class<?>[] getRootConfigClasses() {
        return new Class<?>[] { RootConfig.class };
    }

    @Override
    protected Class<?>[] getServletConfigClasses() {
        return new Class<?>[] { WebConfig.class };
    }

    @Override
    protected String[] getServletMappings() {
        return new String[] { "/" };
    }

}

WebConfig.java

package com.spitter.config;

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.ViewResolver;
import org.springframework.web.servlet.config.annotation.DefaultServletHandlerConfigurer;
import org.springframework.web.servlet.config.annotation.EnableWebMvc;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurerAdapter;
import org.springframework.web.servlet.view.InternalResourceViewResolver;

@Configuration
@EnableWebMvc
@ComponentScan("com.spitter.web")
public class WebConfig extends WebMvcConfigurerAdapter {

    @Bean
    public ViewResolver viewResolver() {
        InternalResourceViewResolver resolver = new InternalResourceViewResolver();
        resolver.setPrefix("/WEB-INF/views/");
        resolver.setSuffix(".jsp");
        resolver.setExposeContextBeansAsAttributes(true);
        return resolver;
    }

    @Override
    public void configureDefaultServletHandling(DefaultServletHandlerConfigurer configurer) {
        configurer.enable();
    }

}

RootConfig.java

package com.spitter.config;

import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.ComponentScan.Filter;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.FilterType;
import org.springframework.web.servlet.config.annotation.EnableWebMvc;

@Configuration
@ComponentScan(basePackages = { "com.spitter.data" }, excludeFilters = {@Filter(type = FilterType.ANNOTATION, value = EnableWebMvc.class) })
public class RootConfig {

}

Answer 1

正如@mh-dev 所解释的，您需要 SpittleRepository 的实现。尝试添加此 class 并查看您的代码是否可以运行:

public class SpittleRepositoryImpl implements SpittleRepository {

  List <Spittle> findSpittles(long max, int count) {
    System.out.println("I need a real implementation! " 
      + "I received max as " + max + " and count as " + count + ".");
  }

}

我建议您重新阅读本书的相关部分，以确保您没有遗漏任何内容。

Answer 2

这里是存储库的实现：

package com.spitter.web;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;

import com.spitter.data.SpittleRepository;

@Controller
@RequestMapping("/spittles")
public class SpittleController {

    private SpittleRepository spittleRepository;

    @Autowired
    public SpittleController(SpittleRepository spittleRepository) {
        this.spittleRepository = spittleRepository;
    }

    @RequestMapping(method = RequestMethod.GET)
    public String spittles(Model model) {
        model.addAttribute("spittleList", spittleRepository.findSpittles(Long.MAX_VALUE, 20));
        return "spittles";
    }

}

Answer 3

我知道这个密码。 2 年前它曾经让我严重头痛。错误在代码中或书本身。

转到发布者站点并下载更新的源代码。 here

或

https://www.manning.com/books/spring-in-action-fourth-edition

Answer 4

是的，问题是您需要 SpittleRepository 的实现。因为你不能有一个接口作为 bean，你知道的。扫描组件至少需要它的一个实现并带有注解@Component。就这样 ;)

Answer 5

您只需要在 header 中添加带有 @Repository 的 SpittleRepository 的存储库实现，因为即使您添加了实现类，spring IOC 也不知道实际的依赖性如果您将所有 java 文件放在具有存储库实现的同一包层次结构中，书中的示例应该有效。

@Repository
public class SpittleRepositoryDAO implements SpittleRepository {

    public SpittleRepositoryDAO() {

    }

    @Override
    public List<Spittle> findSpittles(long max, int count) {
        List<Spittle> spittles = new ArrayList<Spittle>();
        for (int i = 0; i < count; i++) {
            spittles.add(new Spittle("Spittle " + i, new Date()));
        }
        return spittles;
    }
}

Spitter 不满足依赖异常 Spring MVC

Spitter Unsatisfied Dependency Exception Spring MVC

java

spring

action

spring-mvc