尝试使用 Spring JDBC 使用数据库，但显示 noclassdeffounderror

Question

` 错误消息我收到错误：-NoClassDefFoundError

12：19：07.250 [主要]调试 org.springframework.context.support.ClassPathXmlApplicationContext - 刷新 org.springframework.context.support.ClassPathXmlApplicationContext@24b1d79b 线程“main”中的异常 java.lang.NoClassDefFoundError: org/springframework/core/metrics/ApplicationStartup 在org.springframework.beans.factory.support.AbstractBeanFactory。（AbstractBeanFactory.java：184） 在org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory。（AbstractAutowireCapableBeanFactory.java：176） 在org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory。（AbstractAutowireCapableBeanFactory.java：193） 在 org.springframework.beans.factory.support.DefaultListableBeanFactory。（DefaultListableBeanFactory.java:201） 在org.springframework.context.support.AbstractRefreshableApplicationContext.createBeanFactory（AbstractRefreshableApplicationContext.java:197） 在org.springframework.context.support.AbstractRefreshableApplicationContext.refreshBeanFactory（AbstractRefreshableApplicationContext.java:127） 在org.springframework.context.support.AbstractApplicationContext.obtainFreshBeanFactory（AbstractApplicationContext.java:638） 在org.springframework.context.support.AbstractApplicationContext.refresh（AbstractApplicationContext.java:523） 在org.springframework.context.support.ClassPathXmlApplicationContext。（ClassPathXmlApplicationContext.java：144） 在 org.springframework.context.support.ClassPathXmlApplicationContext。（ClassPathXmlApplicationContext.java:85） 在 jdbc.mainioc.main(mainioc.java:12) 引起原因：java.lang.ClassNotFoundException：org.springframework.core.metrics.ApplicationStartup 在 java.base/jdk.internal.loader.BuiltinClassLoader.loadClass(BuiltinClassLoader.java:641) 在 java.base/jdk.internal.loader.ClassLoaders$AppClassLoader.loadClass(ClassLoaders.java:188) 在 java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:525) ... 11 更多

import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import org.springframework.jdbc.core.JdbcTemplate;

public class mainioc 
{

    public static void main(String[] args) 
    {
        
        ApplicationContext ctx=new ClassPathXmlApplicationContext("Appmeta.xml");
    JdbcTemplate temp= (JdbcTemplate) ctx.getBean("dataS");
    //insert query 
    String query="insert into employee(id,name,salary) values(?,?,?)";
                
    //fire query 
    int result=temp.update(query,3,"ram",14578);
    System.out.println("record inserted"+ result );
}
}



i try to add dependency spring starter
<dependency>
  <groupId>org.springframework.boot</groupId>
  <artifactId>spring-boot-starter-web</artifactId>
  <version>2.3.3.RELEASE</version>
</dependency>




myentity class
package com.spjdbc.entity;



public class student 
{
 private String id;
 private String Sname;
 private String Srollno;

 @Override
public String toString() 
 {
    return "student [id=" + id + ", Sname=" + Sname + ", Srollno=" + Srollno + "]";
}
public String getId() 
{
    return id;
}
public void setId(String id) 
{
    this.id = id;
}
public String getSname() 
{
    return Sname;
}
public void setSname(String sname) 
{
    Sname = sname;
}
public String getSrollno() 
{
    return Srollno;
}
public void setSrollno(String srollno) 
{
    Srollno = srollno;
}
 

}



meta file 

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:p="http://www.springframework.org/schema/p"
       xsi:schemaLocation="http://www.springframework.org/schema/context 
       http://www.springframework.org/schema/context/spring-context-4.0.xsd 
       http://www.springframework.org/schema/beans 
       http://www.springframework.org/schema/beans/spring-beans-3.0.xsd">
<bean id="DataS" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
<property name="driverClassName" value="com.mysql.cj.jdbc.Driver"/>
<property name="url" value="jdbc:mysql://localhost:3306/studentdb"/>
<property name="username" value="root"/>
<property name="password" value="root"/>
</bean>

<bean id="jdbcB" class="org.springframework.jdbc.core.JdbcTemplate">
<property name="dataSource" ref="DataS"/>
</bean>

</beans>




test file 
package com.spjdbc.ioc;

import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;
import org.springframework.jdbc.core.JdbcTemplate;


public class iocmain {

    public static void main(String[] args) 
    {
    ApplicationContext  cont= new AnnotationConfigApplicationContext("com/spjdbc/ioc/BeanConf.class");
    JdbcTemplate temp= cont.getBean(JdbcTemplate.class);
    String query="insert into student(id,Sname,Srollno) values(?,?,?)";
    int result = temp.update(query,1,"ram",24001);
    System.out.println("intert the value" +result);

    }

}


Annotation 

package com.spjdbc.ioc;

import javax.sql.DataSource;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.jdbc.datasource.DriverManagerDataSource;
@Configuration
public class BeanConf 
{
    @Bean
    public DataSource dataSource() 
    {
        DriverManagerDataSource dataSource = new DriverManagerDataSource(); 
        dataSource.setDriverClassName("com.mysql.cj.jdbc.Driver");
        dataSource.setUrl("jdbc:mysql://localhost:3306/studentdb");
        dataSource.setUsername("root");
        dataSource.setPassword("root");
        return dataSource;
    }
    
    @Bean
    public JdbcTemplate jdbcTemplate() 
    {
        return new JdbcTemplate(dataSource());
    }
    
}


how can i resolve the issue Bean not accessesible itry both the form XML aand Annotation but cant work 

Answer 1

您需要将 Spring Data JPA 的依赖项以及要使用的数据库连接器 (MySQL) 添加到您的

pom.xml

。:

    <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-data-jpa</artifactId>
    </dependency>

    <dependency>
      <groupId>com.mysql</groupId>
      <artifactId>mysql-connector-j</artifactId>
      <scope>runtime</scope>
    </dependency>

这些取自https://start.spring.io/