Question

我正在尝试使用spring，hibernate，jpa，maven创建我的第一个Java Web项目。我用注解代替xml配置spring，并且tomcat服务器正在正确初始化，但是当我尝试使用“ EntityManager”从数据库中的html页面添加产品时，出现以下错误：

jul 24, 2018 7:55:44 PM org.apache.catalina.core.StandardWrapperValve invoke
GRAVE: Servlet.service() for servlet [dispatcher] in context with path [/eCommerce] threw exception [Request processing failed; nested exception is org.springframework.transaction.CannotCreateTransactionException: Could not open JPA EntityManager for transaction; nested exception is javax.persistence.PersistenceException: org.hibernate.exception.GenericJDBCException: Could not open connection] with root cause
java.lang.NullPointerException
    at com.mysql.jdbc.ConnectionImpl.getServerCharset(ConnectionImpl.java:3005)
    at com.mysql.jdbc.MysqlIO.sendConnectionAttributes(MysqlIO.java:1916)
    at com.mysql.jdbc.MysqlIO.proceedHandshakeWithPluggableAuthentication(MysqlIO.java:1845)
    at com.mysql.jdbc.MysqlIO.doHandshake(MysqlIO.java:1215)
    at com.mysql.jdbc.ConnectionImpl.coreConnect(ConnectionImpl.java:2255)
    at com.mysql.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:2286)
    at com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2085)
    at com.mysql.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:795)
    at com.mysql.jdbc.JDBC4Connection.<init>(JDBC4Connection.java:44)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)
    at java.lang.reflect.Constructor.newInstance(Unknown Source)
    at com.mysql.jdbc.Util.handleNewInstance(Util.java:404)
    at com.mysql.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:400)
    at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:327)
    at org.apache.commons.dbcp2.DriverConnectionFactory.createConnection(DriverConnectionFactory.java:39)
    at org.apache.commons.dbcp2.PoolableConnectionFactory.makeObject(PoolableConnectionFactory.java:256)
    at org.apache.commons.dbcp2.BasicDataSource.validateConnectionFactory(BasicDataSource.java:2304)
    at org.apache.commons.dbcp2.BasicDataSource.createPoolableConnectionFactory(BasicDataSource.java:2290)
    at org.apache.commons.dbcp2.BasicDataSource.createDataSource(BasicDataSource.java:2039)
    at org.apache.commons.dbcp2.BasicDataSource.getConnection(BasicDataSource.java:1533)
    at org.hibernate.engine.jdbc.connections.internal.DatasourceConnectionProviderImpl.getConnection(DatasourceConnectionProviderImpl.java:139)
    at org.hibernate.internal.AbstractSessionImpl$NonContextualJdbcConnectionAccess.obtainConnection(AbstractSessionImpl.java:380)
    at org.hibernate.engine.jdbc.internal.LogicalConnectionImpl.obtainConnection(LogicalConnectionImpl.java:228)
    at org.hibernate.engine.jdbc.internal.LogicalConnectionImpl.getConnection(LogicalConnectionImpl.java:171)
    at org.hibernate.engine.transaction.internal.jdbc.JdbcTransaction.doBegin(JdbcTransaction.java:67)
    at org.hibernate.engine.transaction.spi.AbstractTransactionImpl.begin(AbstractTransactionImpl.java:162)
    at org.hibernate.internal.SessionImpl.beginTransaction(SessionImpl.java:1435)
    at org.hibernate.jpa.internal.TransactionImpl.begin(TransactionImpl.java:61)
    at org.springframework.orm.jpa.vendor.HibernateJpaDialect.beginTransaction(HibernateJpaDialect.java:166)
    at org.springframework.orm.jpa.JpaTransactionManager.doBegin(JpaTransactionManager.java:380)
    at org.springframework.transaction.support.AbstractPlatformTransactionManager.getTransaction(AbstractPlatformTransactionManager.java:373)
    at org.springframework.transaction.interceptor.TransactionAspectSupport.createTransactionIfNecessary(TransactionAspectSupport.java:463)
    at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:276)
    at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:96)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
    at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:213)
    at com.sun.proxy.$Proxy39.addProduct(Unknown Source)
    at com.pedro.ecommerce.controller.ProductsControll.addProduct(ProductsControll.java:26)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
    at java.lang.reflect.Method.invoke(Unknown Source)
    at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:205)
    at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:133)
    at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:97)
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:827)
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:738)
    at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:85)
    at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:967)
    at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:901)
    at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:970)
    at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:872)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:661)
    at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:846)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:742)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
    at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:198)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96)
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:493)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:140)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:81)
    at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:650)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:87)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:342)
    at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:800)
    at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66)
    at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:800)
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1471)
    at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
    at java.lang.Thread.run(Unknown Source)

我整日搜索解决方案，发现了很多类似的案例，但是没有一个解决我的问题，因此，如果有更多专业知识的人可以帮助我，我将不胜感激:)

这是项目树：

配置类：

包com.pedro.ecommerce.config;

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

public class WebInit extends AbstractAnnotationConfigDispatcherServletInitializer{
@Override
protected Class<?>[] getRootConfigClasses() {
    System.out.println("rootConfigClasses in");
    return new Class[] { SpringConfig.class, SpringJpaConfig.class };
}

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

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

}

包com.pedro.ecommerce.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.view.InternalResourceViewResolver;

@EnableWebMvc
@Configuration
@ComponentScan(basePackages="com.pedro.ecommerce")

public class SpringConfig {

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

}

包com.pedro.ecommerce.config;

import javax.persistence.EntityManagerFactory;
import javax.sql.DataSource;
//org.apache.commons.dbcp2.BasicDataSource;
import org.apache.commons.dbcp2.BasicDataSource;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.PropertySource;
import org.springframework.core.env.Environment;
import org.springframework.orm.jpa.JpaTransactionManager;
import org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean;
import org.springframework.orm.jpa.vendor.HibernateJpaDialect;
import org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter;
import org.springframework.transaction.PlatformTransactionManager;
import org.springframework.transaction.annotation.EnableTransactionManagement;

@Configuration
@EnableTransactionManagement
@PropertySource("classpath:/application.properties")
public class SpringJpaConfig {

    @Autowired
    private Environment env;

    @Bean
    @Autowired
    public PlatformTransactionManager transactionManager(EntityManagerFactory factory) {
        System.out.println("in transactionManager");
        JpaTransactionManager manager = new JpaTransactionManager();
        manager.setEntityManagerFactory(factory);
        manager.setJpaDialect(new HibernateJpaDialect());
        System.out.println("out transactionManager");
        return manager;
    }

    @Bean
    public HibernateJpaVendorAdapter jpaVendorAdapter() {
        HibernateJpaVendorAdapter adapter = new HibernateJpaVendorAdapter();
        adapter.setShowSql(env.getProperty("hibernate.show_sql", Boolean.class));
        adapter.setGenerateDdl(env.getProperty("hibernate.generate_dll", Boolean.class));
        adapter.setDatabasePlatform(env.getProperty("hibernate.dialect", String.class));

        return adapter;
    }

    @Bean(name="dataSource")
    public DataSource dataSource() {
        System.out.println("in dataSource");
        BasicDataSource dataSource = new BasicDataSource();
        dataSource.setUsername(env.getProperty("jdbc.username"));
        dataSource.setPassword(env.getProperty("jdbc.password"));
        dataSource.setDriverClassName(env.getProperty("jdbc.driverClassName"));
        dataSource.setUrl(env.getProperty("jdbc.url"));
        System.out.println("out dataSource");
        return dataSource;
    }

    @Bean
    public EntityManagerFactory entityManagerFactory() {
        System.out.println("in entityM");
        LocalContainerEntityManagerFactoryBean factory = new LocalContainerEntityManagerFactoryBean();
        factory.setJpaVendorAdapter(jpaVendorAdapter());
        factory.setPackagesToScan("com.pedro.ecommerce.model");
        factory.setDataSource(dataSource());
        factory.afterPropertiesSet();
        System.out.println("out entityM");
        return factory.getObject();
    }
}

模型类：

package com.pedro.ecommerce.model;

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.Table;

import org.hibernate.annotations.GenericGenerator;

@Entity
@Table(name="PRODUCTS")
public class Product {
    @Id
    @GeneratedValue(generator="increment") //works with "GenericGenerator" to define the id as a incremented value 
    @GenericGenerator(name="increment", strategy="increment")
    @Column(name="idProduct")
    private int id;

    //not null
    @Column(name="nameProduct")
    private String name;

    //not null
    @Column(name="priceProduct")
    private float price;

    @Column(name="descProduct")
    private String description;

    @Column(name="imageProduct")
    private String imageDirectory;

    public Product() { }

    public int getId() { return id; }
    public void setId(int id) { this.id = id; }
    public String getName() { return name; }
    public void setName(String name) { this.name = name; }
    public float getPrice() { return price; }
    public void setPrice(float price) { this.price = price; }
    public String getDescription() { return description; }
    public void setDescription(String description) { this.description = description; }
    public String getImageDirectory() { return imageDirectory; }
    public void setImageDirectory(String imageDirectory) { this.imageDirectory = imageDirectory; }
}

Dao类：

    package com.pedro.ecommerce.dao;

import java.util.List;

import javax.persistence.EntityManager;
import javax.persistence.PersistenceContext;

import org.springframework.stereotype.Repository;
import org.springframework.transaction.annotation.Transactional;

import com.pedro.ecommerce.model.Product;


@Repository("productDaoImpl")
@Transactional
public class ProductDaoImpl implements ProductDao{

    @PersistenceContext
    private EntityManager manager;

    @Override                               
    public void addProduct(Product product) {
        manager.persist(product);
    }

    @Override
    public void removeProductById(int id) {

    }

    @Override
    public Product findProductById(int id) {

        return null;
    }

    @Override
    public List<Product> findAllProducts() {

        return null;
    }

    @Override
    public List<Product> findTwentyBestProducts() {

        return null;
    }

    public EntityManager getManager() {
        return manager;
    }

    public void setManager(EntityManager manager) {
        this.manager = manager;
    }
}

控制类：

    package com.pedro.ecommerce.controller;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;

import com.pedro.ecommerce.dao.ProductDao;
import com.pedro.ecommerce.model.Product;

@Controller
public class ProductsControll {

    @Autowired
    @Qualifier("productDaoImpl")
    private ProductDao productDao;

    @RequestMapping("add-product")
    public String getAddForm() {
        return "add-product";
    }

    @RequestMapping("addProduct")
    public String addProduct(Product product) {
        if(this.productDao != null) {
            this.productDao.addProduct(product);

            return "added-product";
        }else {
            System.out.println("productDao = null");
            return "add-product";
        }
    }

}

错误“ org.springframework.transaction.CannotCreateTransactionException：无法打开JPA EntityManager进行交易”

0 个答案: