CODEWITHSUNDEEP
javaspringhibernatespring-bootspring-mvc
saivinay manapuram
saivinay manapuram

Reputation: 69

Getting Bean Creation Exception with name DAO class

While i am building this code i am getting error bean is not creating for DAO class even though annotations are added correctly

WARNING: Exception encountered during context initialization - cancelling refresh attempt: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'bankDaoImpl' defined in file [C:\Users\saivi\eclipse- workspace\bank\target\classes\com\bank\dao\BankDaoImpl.class]: Instantiation of bean failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [com.bank.dao.BankDaoImpl]: Constructor threw exception; nested exception is java.lang.NullPointerException Nov 28, 2019 9:50:45 PM org.springframework.web.context.ContextLoader initWebApplicationContext SEVERE: Context initialization failed org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'bankDaoImpl' defined in file [C:\Users\saivi\eclipse- workspace\bank\target\classes\com\bank\dao\BankDaoImpl.class]: Instantiation of bean failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [com.bank.dao.BankDaoImpl]: Constructor threw exception; nested exception is java.lang.NullPointerException

AppConfig.java

package com.bank.config;

import java.util.Properties;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.ComponentScans;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.PropertySource;
import org.springframework.core.env.Environment;
import org.springframework.orm.hibernate5.HibernateTransactionManager;
import org.springframework.orm.hibernate5.LocalSessionFactoryBean;
import org.springframework.transaction.annotation.EnableTransactionManagement;
import static org.hibernate.cfg.Environment.*;

@Configuration
@PropertySource("classpath:db.properties")
@EnableTransactionManagement
@ComponentScans(value = { @ComponentScan("com.bank.dao"),
      @ComponentScan("com.bank.service") })
public class AppConfig {

   @Autowired
   private Environment env;

   @Bean
   public LocalSessionFactoryBean getSessionFactory() {
      LocalSessionFactoryBean factoryBean = new LocalSessionFactoryBean();

      Properties props = new Properties();
      // Setting JDBC properties
      props.put(DRIVER, env.getProperty("mysql.driver"));
      props.put(URL, env.getProperty("mysql.url"));
      props.put(USER, env.getProperty("mysql.user"));
      props.put(PASS, env.getProperty("mysql.password"));

      // Setting Hibernate properties
      props.put(SHOW_SQL, env.getProperty("hibernate.show_sql"));
      props.put(HBM2DDL_AUTO, env.getProperty("hibernate.hbm2ddl.auto"));

      // Setting C3P0 properties
      props.put(C3P0_MIN_SIZE, env.getProperty("hibernate.c3p0.min_size"));
      props.put(C3P0_MAX_SIZE, env.getProperty("hibernate.c3p0.max_size"));
      props.put(C3P0_ACQUIRE_INCREMENT, 
            env.getProperty("hibernate.c3p0.acquire_increment"));
      props.put(C3P0_TIMEOUT, env.getProperty("hibernate.c3p0.timeout"));
      props.put(C3P0_MAX_STATEMENTS, env.getProperty("hibernate.c3p0.max_statements"));

      factoryBean.setHibernateProperties(props);
      factoryBean.setPackagesToScan("com.bank.model");

      return factoryBean;
   }

   @Bean
   public HibernateTransactionManager getTransactionManager() {
      HibernateTransactionManager transactionManager = new HibernateTransactionManager();
      transactionManager.setSessionFactory(getSessionFactory().getObject());
      return transactionManager;
   }
}

MyWebAppInitializer.java

package com.bank.config;

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

public class MyWebAppInitializer extends AbstractAnnotationConfigDispatcherServletInitializer {

    @Override
    protected Class<?>[] getRootConfigClasses() {

        return new Class[] {AppConfig.class};
    }

    @Override
    protected Class<?>[] getServletConfigClasses() {

        return new Class[] {WebConfig.class};
    }

    @Override
    protected String[] getServletMappings() {

        return new String[] {"/"};
    }

}

WebConfig.java

package com.bank.config;

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

@Configuration
@EnableWebMvc
@ComponentScan(basePackages= {"com.bank.controller"})
public class WebConfig extends WebMvcConfigurerAdapter {

}

Bank.java

package com.bank.model;

import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;

@Entity(name="Bank")
public class Bank {

    @Id
    @GeneratedValue(strategy=GenerationType.IDENTITY)
    private long id;
    private String name;
    private Integer balance;
    public long getId() {
        return id;
    }
    public void setId(long id) {
        this.id = id;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public Integer getBalance() {
        return balance;
    }
    public void setBalance(Integer balance) {
        this.balance = balance;
    }
}

BankDaoImpl.java

package com.bank.dao;

import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Repository;
import com.bank.model.Bank;

@Repository
public class BankDaoImpl implements BankDao{

    @Autowired
    private SessionFactory sessionFactory;
    Session s=sessionFactory.getCurrentSession();


    @Override
    public long save(Bank bank) {
        s.save(bank);
        return bank.getId();
    }
    @Override
    public Bank get(long id) {
        return s.get(Bank.class, id);
    }


    @Override
    public void delete(long id) {
        Bank b=s.byId(Bank.class).load(id);
        s.delete(b);

    }

}

BankService.java

package com.bank.service;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import com.bank.dao.BankDao;
import com.bank.model.Bank;

@Service
@Transactional(readOnly=true)
public class BankServiceImpl implements BankService {

    @Autowired
    private BankDao bankDao;

    @Transactional
    @Override
    public long save(Bank bank) {
        return bankDao.save(bank);
    }

    @Override
    public Bank get(long id) {
        return bankDao.get(id);
    }

    @Override
    public void delete(long id) {
        bankDao.delete(id);

    }

}

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>bank</groupId>
  <artifactId>bank</artifactId>
  <version>0.0.1-SNAPSHOT</version>
  <packaging>war</packaging>

    <properties>
    <failOnMissingWebXml>false</failOnMissingWebXml>
  </properties>

  <dependencies>
    <!-- Spring MVC Dependency -->
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-webmvc</artifactId>
      <version>4.3.10.RELEASE</version>
    </dependency>
    <!-- Spring ORM -->
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-orm</artifactId>
      <version>4.3.10.RELEASE</version>
    </dependency>
    <!-- Hibernate ORM -->
    <dependency>
      <groupId>org.hibernate</groupId>
      <artifactId>hibernate-core</artifactId>
      <version>5.2.11.Final</version>
    </dependency>
    <!-- Hibernate-C3P0 Integration -->
    <dependency>
      <groupId>org.hibernate</groupId>
      <artifactId>hibernate-c3p0</artifactId>
      <version>5.2.11.Final</version>
    </dependency>
    <!-- c3p0 -->
    <dependency>
      <groupId>com.mchange</groupId>
      <artifactId>c3p0</artifactId>
      <version>0.9.5.2</version>
    </dependency>
    <!-- Mysql Connector -->
    <dependency>
      <groupId>mysql</groupId>
      <artifactId>mysql-connector-java</artifactId>
      <version>6.0.5</version>
    </dependency>
    <!-- Jackson API for JSON -->
    <dependency>
      <groupId>com.fasterxml.jackson.core</groupId>
      <artifactId>jackson-databind</artifactId>
      <version>2.8.7</version>
    </dependency>
    <!-- Servlet Dependency -->
    <dependency>
      <groupId>javax.servlet</groupId>
      <artifactId>javax.servlet-api</artifactId>
      <version>3.1.0</version>
      <scope>provided</scope>
    </dependency>
  </dependencies>
  <build>
    <plugins>
      <plugin>
        <artifactId>maven-compiler-plugin</artifactId>
        <version>3.5.1</version>
        <configuration>
          <source>1.8</source>
          <target>1.8</target>
        </configuration>
      </plugin>

      <!-- Embedded Apache Tomcat required for testing web application -->
      <plugin>
        <groupId>org.apache.tomcat.maven</groupId>
        <artifactId>tomcat7-maven-plugin</artifactId>
        <version>2.2</version>
        <configuration>
          <path>/</path>
        </configuration>
      </plugin>
    </plugins>
  </build>
</project>

Upvotes: 0

Views: 1032

Answers (1)

Troley
Troley

Reputation: 1658

The following line in your code sampleSession s=sessionFactory.getCurrentSession(); in BankDaoImpl will cause a NullPointerException, because the SessionFactory object hasn't been Autowired yet and you are already trying to invoke its methods.

Try to replace the line into each of the methods within that class. So for example, your BankDaoImpl#save method will look like this:

public class BankDaoImpl {

    @Autowired
    SessionFactory sessionFactory;

    @Override
    public long save(Bank bank) {
        Session s = sessionFactory.getCurrentSession();
        s.save(bank);
        return bank.getId();
    }
    ...
}

Try to do the above for every other method that uses sessionFactory in the BankDaoImplclass.

Upvotes: 1

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