属性“driverClassName”抛出异常； 无法加载 JDBC 驱动程序类 [org.postgresql.Driver]

Question

我是 Spring 的初学者

我试图测试我与数据库（postgresql）的连接，因此编写了以下简单的代码。 但它抛出了我无法解决的错误。

抛出错误：

Jul 05, 2017 12:01:13 PM org.springframework.context.support.ClassPathXmlApplicationContext prepareRefresh
INFO: Refreshing org.springframework.context.support.ClassPathXmlApplicationContext@4534b60d: startup date [Wed Jul 05 12:01:13 IST 2017]; root of context hierarchy
Jul 05, 2017 12:01:14 PM org.springframework.beans.factory.xml.XmlBeanDefinitionReader loadBeanDefinitions
INFO: Loading XML bean definitions from class path resource [applicationContext.xml]
Jul 05, 2017 12:01:14 PM org.springframework.context.support.ClassPathXmlApplicationContext refresh
WARNING: Exception encountered during context initialization - cancelling refresh attempt
org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'ds' defined in class path resource [applicationContext.xml]: Error setting property values; nested exception is org.springframework.beans.PropertyBatchUpdateException; nested PropertyAccessExceptions (1) are:
PropertyAccessException 1: org.springframework.beans.MethodInvocationException: Property 'driverClassName' threw exception; nested exception is java.lang.IllegalStateException: Could not load JDBC driver class [org.postgresql.Driver]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.applyPropertyValues(AbstractAutowireCapableBeanFactory.java:1514)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1222)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:537)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:476)
    at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:303)
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230)
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:299)
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:194)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:755)
    at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:757)
    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:480)
    at org.springframework.context.support.ClassPathXmlApplicationContext.<init>(ClassPathXmlApplicationContext.java:139)
    at org.springframework.context.support.ClassPathXmlApplicationContext.<init>(ClassPathXmlApplicationContext.java:83)
    at com.javatpoint.Test.main(Test.java:9)
Caused by: org.springframework.beans.PropertyBatchUpdateException; nested PropertyAccessExceptions (1) are:
PropertyAccessException 1: org.springframework.beans.MethodInvocationException: Property 'driverClassName' threw exception; nested exception is java.lang.IllegalStateException: Could not load JDBC driver class [org.postgresql.Driver]
    at org.springframework.beans.AbstractPropertyAccessor.setPropertyValues(AbstractPropertyAccessor.java:121)
    at org.springframework.beans.AbstractPropertyAccessor.setPropertyValues(AbstractPropertyAccessor.java:75)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.applyPropertyValues(AbstractAutowireCapableBeanFactory.java:1510)
    ... 13 more

Exception in thread "main" org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'ds' defined in class path resource [applicationContext.xml]: Error setting property values; nested exception is org.springframework.beans.PropertyBatchUpdateException; nested PropertyAccessExceptions (1) are:
PropertyAccessException 1: org.springframework.beans.MethodInvocationException: Property 'driverClassName' threw exception; nested exception is java.lang.IllegalStateException: Could not load JDBC driver class [org.postgresql.Driver]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.applyPropertyValues(AbstractAutowireCapableBeanFactory.java:1514)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1222)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:537)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:476)
    at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:303)
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230)
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:299)
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:194)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:755)
    at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:757)
    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:480)
    at org.springframework.context.support.ClassPathXmlApplicationContext.<init>(ClassPathXmlApplicationContext.java:139)
    at org.springframework.context.support.ClassPathXmlApplicationContext.<init>(ClassPathXmlApplicationContext.java:83)
    at com.javatpoint.Test.main(Test.java:9)
Caused by: org.springframework.beans.PropertyBatchUpdateException; nested PropertyAccessExceptions (1) are:
PropertyAccessException 1: org.springframework.beans.MethodInvocationException: Property 'driverClassName' threw exception; nested exception is java.lang.IllegalStateException: Could not load JDBC driver class [org.postgresql.Driver]
    at org.springframework.beans.AbstractPropertyAccessor.setPropertyValues(AbstractPropertyAccessor.java:121)
    at org.springframework.beans.AbstractPropertyAccessor.setPropertyValues(AbstractPropertyAccessor.java:75)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.applyPropertyValues(AbstractAutowireCapableBeanFactory.java:1510)
    ... 13 more

我的主类是Employee.java ：

package com.javatpoint;

public class Employee {
    private int id;
    private String name;
    private float salary;

    public Employee() {
    }

    public Employee(int id, String name, float salary) {
        super();
        this.id = id;
        this.name = name;
        this.salary = salary;
    }

    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 getSalary() {
        return salary;
    }

    public void setSalary(float salary) {
        this.salary = salary;
    }

}

我的 Dao 文件是EmployeeDao.java ：

package com.javatpoint;
import org.springframework.jdbc.core.JdbcTemplate;

public class EmployeeDao {
private JdbcTemplate jdbcTemplate;

public void setJdbcTemplate(JdbcTemplate jdbcTemplate) {
    this.jdbcTemplate = jdbcTemplate;
}

public int saveEmployee(Employee e){
    String query="insert into employee values('"+e.getId()+"','"+e.getName()+"','"+e.getSalary()+"')";
    return jdbcTemplate.update(query);
}
public int updateEmployee(Employee e){
    String query="update employee set name='"+e.getName()+"',salary='"+e.getSalary()+"' where id='"+e.getId()+"' ";
    return jdbcTemplate.update(query);
}
public int deleteEmployee(Employee e){
    String query="delete from employee where id='"+e.getId()+"' ";
    return jdbcTemplate.update(query);
}

}

我的 xml 文件是applicationContext.xml ：

<?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/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd">

<bean id="ds" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
<property name="driverClassName" value="org.postgresql.Driver" />    
<property name="url" value="jdbc:postgresql://localhost:5432/Testing" />
<property name="username" value="postgres" />
<property name="password" value="hlinaknk" />
</bean>

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

<bean id="edao" class="com.javatpoint.EmployeeDao">
<property name="jdbcTemplate" ref="jdbcTemplate"></property>
</bean>

</beans>

我的测试文件是Test.java ：

package com.javatpoint;

import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
public class Test {

    public static void main(String[] args) {

        ApplicationContext ctx=new ClassPathXmlApplicationContext("applicationContext.xml");

        EmployeeDao dao=(EmployeeDao)ctx.getBean("edao");

        try {
              Class.forName("org.postgresql.Driver");
              //on classpath
            } catch(ClassNotFoundException e) {
              // not on classpath
            }

        int status=dao.saveEmployee(new Employee(102,"Amit",35000));
        System.out.println(status);

        /*int status=dao.updateEmployee(new Employee(102,"Sonoo",15000));
        System.out.println(status);
        */

        /*Employee e=new Employee();
        e.setId(102);
        int status=dao.deleteEmployee(e);
        System.out.println(status);*/

    }

}

任何人都可以请建议这里发生了什么问题吗？

Answer 1

你有这个错误弹出：

PropertyAccessException 1: org.springframework.beans.MethodInvocationException: Property 'driverClassName' threw exception; nested exception is java.lang.IllegalStateException: Could not load JDBC driver class [org.postgresql.Driver]

测试“org.postgresql.Driver”是否在您的类路径中，如下所示：

try {
  Class.forName("org.postgresql.Driver");
  //on classpath
} catch(ClassNotFoundException e) {
  //not on classpath
}

您可能想阅读这个问题： 获取错误：无法加载 JDBC 驱动程序类 [org.postgresql.Driver]

Answer 2

尽管在我的 maven 项目中添加了 postgresql 依赖项，但我在尝试在 tomcat 7 中运行 war 文件时遇到了这个错误。 我通过更新到tomcat 8然后下载这个文件来解决它： https : //jdbc.postgresql.org/download/postgresql-42.2.5.jar并将其放在tomcat的lib文件夹中。

Answer 3

将 Oracle 的 JDBC 连接器添加到Tomcat/lib/对我有用。

您可以从https://www.oracle.com/database/technologies/appdev/jdbc.html获取，希望对您有所帮助。