Spring创建对象和常用API测试,对Spring框架的解析-----Spring框架

蔚落 2024-03-23 17:24 71阅读 0赞

>     package com.powernode.spring6.test;
>     
>     import com.powernode.Spring6.bean.User;
>     import com.powernode.Spring6.dao.UserDaoImplForMySQL;
>     import org.junit.Test;
>     import org.springframework.beans.factory.BeanFactory;
>     import org.springframework.context.ApplicationContext;
>     import org.springframework.context.support.ClassPathXmlApplicationContext;
>     import org.springframework.context.support.FileSystemXmlApplicationContext;
>     
>     import java.text.SimpleDateFormat;
>     import java.util.Date;
>     
>     public class firstSpringTest
>     {
>         @Test
>         public void TestSpringCode()
>         {
>             //获取Spring容器对象,根据bean的ID获取这个类对象,ApplicationContext翻译为应用上下文,其实就是Spring容器
>             //ApplicationContext是一个接口,这个接口下有很多实现类,其中有一个实现类叫做ClassPathXmlApplicationContext专门从类路径加载Spring配置文件的Spring上下文对象
>             //只要该代码执行,就启动了Spring容器,并且会解析XML文件,并且将对象创建出来,放置在Spring容器中
>             ApplicationContext applicationContext = new ClassPathXmlApplicationContext("spring6.xml","bean.xml","xml/beans.xml");
>             //第二步,根据bean的ID从Spring容器中获取该对象
>             Object userBean = applicationContext.getBean("userBean");
>             System.out.println(userBean);
>             //如果该Bean类没有可调用的无参数构造方法就会报错
>             Object userDao = applicationContext.getBean("userDaoBean");
>             UserDaoImplForMySQL userDaoBean = applicationContext.getBean("userDaoBean",UserDaoImplForMySQL.class);
>             userDaoBean.insert();
>             System.out.println(applicationContext.getBean("vip"));
>             System.out.println(userDao);
>             //Spring将创建好的对象存到一个Map<String,Object>中
>             //key(ID),"userBean",value(bean)User对象
>             Object obj = userBean.getClass();
>             obj = com.powernode.Spring6.bean.User.class;
>             //Spring配置文件的名字可以自拟
>             System.out.println(applicationContext.getBean("userBean2"));
>             obj = applicationContext.getBean("nowTime");
>             System.out.println(obj);
>             SimpleDateFormat simpleDateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss SSS");
>             String nowTime = simpleDateFormat.format((Date)obj);
>             //不强制类型转换方法如下
>             Date date = applicationContext.getBean("nowTime",Date.class);
>             //通过第二个参数指定返回类型
>             nowTime = simpleDateFormat.format(date);
>             //如果bean的ID不存在,不会返回Null,而是直接报异常信息
>     //        obj = applicationContext.getBean("nowTime2");
>             System.out.println(nowTime);
>         }
>         @Test
>         public void TestXMLPath()
>         {
>             //FileSystemXmlApplicationContext不是从类路径中加载xml
>             ApplicationContext applicationContext = new FileSystemXmlApplicationContext("D:\\File\\Spring6\\Spring6-002-first\\target\\classes\\spring6.xml");
>             User u = applicationContext.getBean("userBean", User.class);
>             System.out.println(u);
>         }
>         @Test
>         public void TestXMLBeanFactory()
>         {
>             //ApplicationContext接口的超级父接口是BeanFactory,即Bean工厂,能够生产bean对象的一个工厂对象,他是IOC容器的超级接口
>             //Spring容器IOC底层实际上使用了工厂模式和XML解析加反射机制
>             BeanFactory beanFactory = new ClassPathXmlApplicationContext("spring6.xml");
>             User u = beanFactory.getBean("userBean",User.class);
>             System.out.println(u);
>         }
>         @Test
>         public void TestBeginInitBean()
>         {
>             //不是在getBean方法调用时才创建对象,执行解析xml文件时就已经创建对象了
>             new ClassPathXmlApplicationContext("spring6.xml");
>         }
>     }
> 
> package com.powernode.spring6.test;  
>   
> import com.powernode.Spring6.bean.User;  
> import com.powernode.Spring6.dao.UserDaoImplForMySQL;  
> import org.junit.Test;  
> import org.springframework.beans.factory.BeanFactory;  
> import org.springframework.context.ApplicationContext;  
> import org.springframework.context.support.ClassPathXmlApplicationContext;  
> import org.springframework.context.support.FileSystemXmlApplicationContext;  
>   
> import java.text.SimpleDateFormat;  
> import java.util.Date;  
>   
> public class firstSpringTest  
> \{  
> @Test  
> public void TestSpringCode()  
> \{  
> //获取Spring容器对象,根据bean的ID获取这个类对象,ApplicationContext翻译为应用上下文,其实就是Spring容器  
> //ApplicationContext是一个接口,这个接口下有很多实现类,其中有一个实现类叫做ClassPathXmlApplicationContext专门从类路径加载Spring配置文件的Spring上下文对象  
> //只要该代码执行,就启动了Spring容器,并且会解析XML文件,并且将对象创建出来,放置在Spring容器中  
> ApplicationContext applicationContext = new ClassPathXmlApplicationContext("spring6.xml","bean.xml","xml/beans.xml");  
> //第二步,根据bean的ID从Spring容器中获取该对象  
> Object userBean = applicationContext.getBean("userBean");  
> System.out.println(userBean);  
> //如果该Bean类没有可调用的无参数构造方法就会报错  
> Object userDao = applicationContext.getBean("userDaoBean");  
> UserDaoImplForMySQL userDaoBean = applicationContext.getBean("userDaoBean",UserDaoImplForMySQL.class);  
> userDaoBean.insert();  
> System.out.println(applicationContext.getBean("vip"));  
> System.out.println(userDao);  
> //Spring将创建好的对象存到一个Map<String,Object>中  
> //key(ID),"userBean",value(bean)User对象  
> Object obj = userBean.getClass();  
> obj = com.powernode.Spring6.bean.User.class;  
> //Spring配置文件的名字可以自拟  
> System.out.println(applicationContext.getBean("userBean2"));  
> obj = applicationContext.getBean("nowTime");  
> System.out.println(obj);  
> SimpleDateFormat simpleDateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss SSS");  
> String nowTime = simpleDateFormat.format((Date)obj);  
> //不强制类型转换方法如下  
> Date date = applicationContext.getBean("nowTime",Date.class);  
> //通过第二个参数指定返回类型  
> nowTime = simpleDateFormat.format(date);  
> //如果bean的ID不存在,不会返回Null,而是直接报异常信息  
> // obj = applicationContext.getBean("nowTime2");  
> System.out.println(nowTime);  
> \}  
> @Test  
> public void TestXMLPath()  
> \{  
> //FileSystemXmlApplicationContext不是从类路径中加载xml  
> ApplicationContext applicationContext = new FileSystemXmlApplicationContext("D:\\\\File\\\\Spring6\\\\Spring6-002-first\\\\target\\\\classes\\\\spring6.xml");  
> User u = applicationContext.getBean("userBean", User.class);  
> System.out.println(u);  
> \}  
> @Test  
> public void TestXMLBeanFactory()  
> \{  
> //ApplicationContext接口的超级父接口是BeanFactory,即Bean工厂,能够生产bean对象的一个工厂对象,他是IOC容器的超级接口  
> //Spring容器IOC底层实际上使用了工厂模式和XML解析加反射机制  
> BeanFactory beanFactory = new ClassPathXmlApplicationContext("spring6.xml");  
> User u = beanFactory.getBean("userBean",User.class);  
> System.out.println(u);  
> \}  
> @Test  
> public void TestBeginInitBean()  
> \{  
> //不是在getBean方法调用时才创建对象,执行解析xml文件时就已经创建对象了  
> new ClassPathXmlApplicationContext("spring6.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"
>            xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd">
>         
>         
>         
>         
>         <bean id="userBean" class="com.powernode.Spring6.bean.User"/>
>     
>         <bean id="userDaoBean" class="com.powernode.Spring6.dao.UserDaoImplForMySQL"/>
>         <bean id="nowTime" class="java.util.Date"/>
>     </beans>
> 
> <?xml version="1.0" encoding="UTF-8"?>  
> <beans xmlns="http://www.springframework.org/schema/beans"  
> xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"  
> xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd">  
>   
>   
>   
>   
> <bean id="userBean" class="com.powernode.Spring6.bean.User"/>  
>   
> <bean id="userDaoBean" class="com.powernode.Spring6.dao.UserDaoImplForMySQL"/>  
> <bean id="nowTime" class="java.util.Date"/>  
> </beans>

>     package com.powernode.Spring6.bean;
>     
>     public class User
>     {
>         //Spring是通过反射机制,调用类的无参数构造方法来实例化对象
>         //原理如下,Class clazz = Class.forName();Object o = clazz.newInstance();
>         public User()
>         {
>             System.out.println("我在这了");
>         }
>         public User(String s)
>         {
>     
>         }
>         //这是一个Bean,封装了用户的信息,Spring可以帮我们创建对象
>     }
> 
> package com.powernode.Spring6.bean;  
>   
> public class User  
> \{  
> //Spring是通过反射机制,调用类的无参数构造方法来实例化对象  
> //原理如下,Class clazz = Class.forName();Object o = clazz.newInstance();  
> public User()  
> \{  
> System.out.println("我在这了");  
> \}  
> public User(String s)  
> \{  
>   
> \}  
> //这是一个Bean,封装了用户的信息,Spring可以帮我们创建对象  
> \}

>     package com.powernode.Spring6.dao;
>     
>     public class UserDaoImplForMySQL
>     {
>         public void insert()
>         {
>             System.out.println("MySQL");
>         }
>     }
> 
> package com.powernode.Spring6.dao;  
>   
> public class UserDaoImplForMySQL  
> \{  
> public void insert()  
> \{  
> System.out.println("MySQL");  
> \}  
> \}