小编Rob*_*use的帖子

我查看了文档来定义bean.我只是不清楚用于Mysql数据库的类文件.任何人都可以填写下面的bean定义吗？

<bean name="dataSource" class="">
    <property name="driverClassName" value="" />
    <property name="url" value="mysql://localhost/GameManager" />
    <property name="username" value="gamemanagertest" />
    <property name="password" value="1" />
</bean>

我正在练习Spring,当我尝试实例化上下文时,我得到了一个java.lang.ExceptionInInitializerError异常.下面显示了Exception,我的代码跟随它.我从以前简化了我的实验.

例外

Oct 17, 2012 5:54:22 PM org.springframework.context.support.AbstractApplicationContext prepareRefresh
INFO: Refreshing org.springframework.context.support.ClassPathXmlApplicationContext@570c16b7: startup date [Wed Oct 17 17:54:22 CDT 2012]; root of context hierarchy
Exception in thread "main" java.lang.ExceptionInInitializerError
at org.springframework.context.support.AbstractRefreshableApplicationContext.createBeanFactory(AbstractRefreshableApplicationContext.java:195)
at org.springframework.context.support.AbstractRefreshableApplicationContext.refreshBeanFactory(AbstractRefreshableApplicationContext.java:128)
at org.springframework.context.support.AbstractApplicationContext.obtainFreshBeanFactory(AbstractApplicationContext.java:535)
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:449)
at org.springframework.context.support.ClassPathXmlApplicationContext.<init>(ClassPathXmlApplicationContext.java:139)
at org.springframework.context.support.ClassPathXmlApplicationContext.<init>(ClassPathXmlApplicationContext.java:83)
at helloworld.HelloWorldTest.main(HelloWorldTest.java:13)
Caused by: java.lang.NullPointerException
at org.springframework.beans.factory.support.DefaultListableBeanFactory.<clinit>(DefaultListableBeanFactory.java:105)
... 7 more

我的配置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:c="http://www.springframework.org/schema/c"
xmlns:p="http://www.springframework.org/schema/p"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.1.xsd">

<bean id="messageContainer" class="helloworld.MessageContainer">
    <property name="message" value="Hello World">
    </property>
</bean>

<bean id="messageOutputService" class="helloworld.MessageOutputService">
</bean>

我的考试班.

package helloworld;

import org.springframework.context.ApplicationContext; …

我正在将Mysql数据库建模为Java中的练习.个人实验.并且我想将表排序规则存储为字符串,因为列可以具有与表不同的排序规则,我还需要为每个列存储它.如果列的collat​​ion字段只能指向表的collat​​ion字段,那将非常有用.但我知道Java没有指针.

您是否知道如何将一个对象的字段指向另一个对象的字段,以便两者始终匹配？

在Java中是否可以基于字段值调用方法？例如,我问用户他们想要什么苏打水.他们输入他们的选择,并且用于保存其选择的字段的值用于调用该方法.

显然下面的代码不起作用.但我希望它能说明我的意图.这种事情在Java中甚至可能吗？

目标是在不使用IF或SWITCH语句的情况下有效切换.

import java.util.Scanner;

public class FieldResolutionTest
{
     public static void main (String[] args)
     {
         Scanner inputScanner = new Scanner(System.in);
         MethodTester test = new MethodTester();

         System.out.println("Please enter ONE or TWO");
         String selection = inputScanner.nextLine();

         test.(selection)();
     }
}

public class MethodTester
{
     public void ONE()
     {
         System.out.println("You ran method ONE");
     }

     public void TWO()
     {
         System.out.println("You ran method TWO");
     }
}

我在测试Spring Junit测试配置时遇到了NullPointerException.问题在于使用@ContextConfiguration和@Autowired注释.

当我实例化上下文并直接获得对bean的引用时,如测试方法中注释掉的代码所示,测试正确运行并成功.但是当我尝试使用@ContextConfiguration和@autowired注释时,使用相同的XML文件属性,我在assertEquals语句中得到一个NullPointerException.你知道我做错了什么吗？

package com.greathouse.helloworld.HelloWorldTest;

import javax.inject.Inject;

import org.junit.Before;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
import junit.framework.TestCase;

@ContextConfiguration(locations = {"classpath:/resources/application-config.xml"})
@RunWith(SpringJUnit4ClassRunner.class)
public class AppTest extends TestCase
{
    @Autowired
    MessageService messageService;

    @Test
    public void testApp()
    {
        //ApplicationContext context = new ClassPathXmlApplicationContext("classpath:/resources/application-config.xml");
        //messageService = context.getBean("printMessage", MessageService.class);
        assertEquals( messageService.getMessage(), "Hello World" );
    }
}