严重：为 servlet [dispatcher] org.springframework.beans.factory.NoSuchBeanDefinitionException 分配异常：

问题描述

我有 expanda.js。我在我的 formcontroller.java 文件中调用这个 dao，但出现以下错误。

我想我需要将 DAO 定义为 bean。如何在 SpringWebConfig.java 文件中执行此操作？

我对春天没有太多控制权，抱歉

控制台错误：

严重：为 servlet [调度程序] 分配异常 org.springframework.beans.factory.NoSuchBeanDeFinitionException：没有可用的“com.esma.dao.ExpDao”类型的合格bean：预期 至少 1 个 bean 有资格作为自动装配候选者。依赖 注释： {@org.springframework.beans.factory.annotation.Autowired(required=true)} 在 org.springframework.beans.factory.support.DefaultListablebeanfactory.raiseNoMatchingBeanFound(DefaultListablebeanfactory.java:1777) 在 org.springframework.beans.factory.support.DefaultListablebeanfactory.doResolveDependency(DefaultListablebeanfactory.java:1333) 在 org.springframework.beans.factory.support.DefaultListablebeanfactory.resolveDependency(DefaultListablebeanfactory.java:1287) 在 org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:640) 在 org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:130) 在 org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessproperties(AutowiredAnnotationBeanPostProcessor.java:399) 在 org.springframework.beans.factory.support.AbstractAutowireCapablebeanfactory.populateBean(AbstractAutowireCapablebeanfactory.java:1415) 在 org.springframework.beans.factory.support.AbstractAutowireCapablebeanfactory.doCreateBean(AbstractAutowireCapablebeanfactory.java:608) 在 org.springframework.beans.factory.support.AbstractAutowireCapablebeanfactory.createBean(AbstractAutowireCapablebeanfactory.java:531) 在 org.springframework.beans.factory.support.Abstractbeanfactory.lambda$doGetBean$0(Abstractbeanfactory.java:335) 在 org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:234) 在 org.springframework.beans.factory.support.Abstractbeanfactory.doGetBean(Abstractbeanfactory.java:333) 在 org.springframework.beans.factory.support.Abstractbeanfactory.getBean(Abstractbeanfactory.java:208) 在 org.springframework.beans.factory.support.DefaultListablebeanfactory.preInstantiateSingletons(DefaultListablebeanfactory.java:944) 在 org.springframework.context.support.AbstractApplicationContext.finishbeanfactoryInitialization(AbstractApplicationContext.java:925) 在 org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:588) 在 org.springframework.web.servlet.FrameworkServlet.configureAndRefreshWebApplicationContext(FrameworkServlet.java:702) 在 org.springframework.web.servlet.FrameworkServlet.initWebApplicationContext(FrameworkServlet.java:578) 在 org.springframework.web.servlet.FrameworkServlet.initServletBean(FrameworkServlet.java:530) 在 org.springframework.web.servlet.HttpServletBean.init(HttpServletBean.java:170) 在 javax.servlet.GenericServlet.init(GenericServlet.java:158) 在 org.apache.catalina.core.StandardWrapper.initServlet(StandardWrapper.java:1134) 在 org.apache.catalina.core.StandardWrapper.allocate(StandardWrapper.java:777) 在 org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:135) 在 org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:97) 在 org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:541) 在 org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:143) 在 org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92) 在 org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:690) 在 org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:78) 在 org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:343) 在 org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:374) 在 org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65) 在 org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:868) 在 org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1590) 在 org.apache.tomcat.util.net.socketProcessorBase.run(SocketProcessorBase.java:49) 在 java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128) 在 java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628) 在 org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) 在 java.base/java.lang.Thread.run(Thread.java:830)

ExpDao.java

package com.esma.dao;

import java.sql.ResultSet;    
import java.sql.sqlException;    
import java.util.List;    
import org.springframework.jdbc.core.BeanPropertyRowMapper;    
import org.springframework.jdbc.core.JdbcTemplate;    
import org.springframework.jdbc.core.RowMapper;

import com.esma.model.Expense;    
    
public class ExpDao {    
JdbcTemplate template;    
    
public void setTemplate(JdbcTemplate template) {    
    this.template = template;    
}    
public int save(Expense exp){    
    String sql="insert into Emp99(name,salary,designation) values('"+exp.getExpenseType()+"',"+exp.getQuantity()+","+exp.getPrice()+","+exp.getPaymentDate()+",'"+exp.getNote()+"' )";    
    return template.update(sql);    
}    
       
public List<Expense> getExpenses(){    
    return template.query("select * from expenses",new RowMapper<Expense>(){    
        public Expense mapRow(ResultSet result,int row) throws sqlException {    
            Expense e=new Expense();    
            e.setExpenseType(result.getString(2));    
            e.setQuantity(result.getInt(3));  
            e.setPrice(result.getInt(4));  
            e.setPaymentDate(result.getDate(5));    
            e.setNote(result.getString(6));    

            return e;    
        }    
    });    
}    
}   

SpringRootConfig.js

package com.esma.config;

import org.apache.commons.dbcp2.BasicDataSource;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;


@Configuration
@ComponentScan(basePackages ={"com.esma.dao"})
public class SpringRootConfig {
//Todo: Services,DAO,DataSource,Email Sender or some other business layer beans.
// In production the datasource configuration is done in properties file but for simplicity purpose it is hardcoded here.   
    @Bean
        public BasicDataSource getDataSource(){
            BasicDataSource ds = new BasicDataSource();
            ds.setDriverClassName("com.MysqL.jdbc.Driver");
            ds.setUrl("jdbc:MysqL://localhost:3306/apartmentmanagement");
            ds.setUsername("root");
            ds.setPassword("1234");
            ds.setMaxTotal(2);
            ds.setinitialSize(1);
            ds.setTestOnBorrow(true);
            ds.setValidationQuery("SELECT 1");
            ds.setDefaultAutoCommit(true);
            return ds;
        }
}

SpringWebConfig.js

/**
 * 
 */
package com.esma.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.EnableWebMvc;
import org.springframework.web.servlet.config.annotation.ResourceHandlerRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurerAdapter;
import org.springframework.web.servlet.view.InternalResourceViewResolver;
import org.springframework.web.servlet.view.JstlView;

import com.esma.dao.ExpDao;
import com.esma.model.Expense;

@Configuration
@ComponentScan(basePackages = { "com.esma" })
@EnableWebMvc
public class SpringWebConfig implements WebMvcConfigurer {
    @Override
    public void addResourceHandlers(ResourceHandlerRegistry registry) {
        // Todo Auto-generated method stub
        System.out.println("Inside Resource Handler");
        registry.addResourceHandler("/static/**").addResourceLocations("/static/");

    }

    @Bean
    public ViewResolver viewResolver() {
        InternalResourceViewResolver vr = new InternalResourceViewResolver();
        vr.setViewClass(JstlView.class);
        vr.setPrefix("/WEB-INF/view/");
        vr.setSuffix(".jsp");
        return vr;
    }
    
    @Bean 
    public ExpDao expenceDao() {
        ExpDao exp = new ExpDao();
        exp.setTemplate(com.esma.dao.ExpDao.class);
        return exp;
    }
}

FormController.js

package com.esma.controller;

import java.util.List;

import javax.servlet.http.HttpSession;

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

import com.esma.dao.ExpDao;
import com.esma.model.Expense;

@Controller
public class FormController {

    @Autowired
    ExpDao dao;

    @RequestMapping(value = "/form",method = RequestMethod.GET)
    public String form() {
        new ModelAndView("expense","expenSEObject",new Expense());
        return "expenseForm";// JSP form view
    }

    @RequestMapping(value = "/expense/save",method = RequestMethod.POST)
    public String addExpense(@modelattribute("expenSEObject") Expense expense,ModelMap model) {

        dao.save(expense);

        model.addAttribute("expenseType",expense.getExpenseType());
        model.addAttribute("quantity",expense.getQuantity());
        model.addAttribute("price",expense.getPrice());
        model.addAttribute("paymentDate",expense.getPaymentDate());
        model.addAttribute("note",expense.getNote());

        System.out.println(model.getAttribute("expenseType"));
        System.out.println(model.getAttribute("quantity"));
        System.out.println(model.getAttribute("price"));
        System.out.println(model.getAttribute("paymentDate"));
        System.out.println(model.getAttribute("note"));

        return "result";
    }

    @RequestMapping(value = "/list")
    public String expenseList(Model m) {
        List<Expense> list = dao.getExpenses();
        m.addAttribute("list",list);
        System.out.println("expense");
        return "expenseList";// JSP form view
    }
}

解决方法

你好 Esma，欢迎来到 stackoverflow。

由于您在 SpringWebConfig.js 中使用 @Bean 注释明确声明了类型为 ExpDao 的 bean，因此在 Spring 上下文中注册的 bean 是 expenceDao，它与此代码部分中的方法名称相同：

 @Bean 
public ExpDao expenceDao() {
    ExpDao exp = new ExpDao();
    exp.setTemplate(com.esma.dao.ExpDao.class);
    return exp;
}

因此 Spring 容器将创建并注册一个类型为 ExpDao 的 bean，其名称（或 id ）为 expenceDao（这是方法的名称 expenceDao()

然后你用这部分代码要求 spring 注入一个名为 expDao 的 bean，但它没有找到。

    @Controller
    public class FormController {

     @Autowired
     ExpDao dao;
    // the rest of the code 
    }

因此 spring 将返回一个 NoSuchBeanDefinitionException，因为它没有找到名为 expDao 的 bean。

为了工作，您只需将 SpringWebConfig.java 文件中的方法名称 expenceDao() 更改为 expDao()，以便 spring 创建名称为 expDao 而不是 expenceDao 的 bean。

谢谢。