String框架搭建的基本步骤,及从 IOC & DI 容器中获取 Bean(spring框架bean的配置)--有实现数据库连接池的链接

时间:2021-07-20 19:41:01

  Spring框架的插件springsource-tool-suite-3.4.0.RELEASE-e4.3.1-updatesite(是一个压缩包)导入步骤:

eclipse->help->Instal New Software->点击add,找到该压缩包->选择 Name下面选择带有 /Spring IDC 的多选框->取消最下边的选框  contact all...->next...->finish;

  建立一个java project,在工程目录下(day-1)建立Folder的lib文件夹,放入Spring的五个jar架包放在里面,并且解压:

commons-logging-1.1.1.jar

spring-beans-4.0.0.RELEASE.jar

spring-context-4.0.0.RELEASE.jar

spring-core-4.0.0.RELEASE.jar

spring-expression-4.0.0.RELEASE.jar

  上述步骤完毕后,就建立Spring的配置文件,一个典型的Spring项目,需要建立一个或多个bean的配置文件,建立Spring配置文件的步骤如下:

该工程下的src->other->spring->Spring Bean Configuration File;该文件的后缀为.xml;然后就建立包,java类...

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  以下是在Spring的IOC容器中配置Bean,ApplicationContext 是面向使用 Spring 框架的开发者,几乎所有的应用场合都直接使用ApplicationContext;

  ApplicationContext 的主要实现类,ClassPathXmlApplicationContext:从 类路径下加载配置文件;ApplicationContext 在初始化上下文时就实例化所有单例的 Bean。

  Spring的命名空间的使用(在该配置文件中,类似于标签)如下:

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1.applicationContext.xml的配置文件:基本命名空间bean的使用 及 含有特殊标签<>的使用<![CDATA[<pnapan^-^>]]>

<bean id="helloWorld" class="com.atguigu.spring.beans.Hello">
<property name="name" value="spring"></property> </bean> <bean id="car" class="com.atguigu.spring.beans.Car">
  //此处<constructor-arg value=" "后可添加 类型和索引 type="double" 或 index=”2“>
<constructor-arg value="4234534.21"></constructor-arg>
<constructor-arg value="red"></constructor-arg>
<constructor-arg value="baoma"></constructor-arg>
</bean> <bean id="person" class="com.atguigu.spring.beans.Person">
<property name="name">
<value><![CDATA[<pnapan^-^>]]></value>
</property>
<property name="age" value="24"></property>
<property name="car" ref="car"></property>
</bean>

src 目录下的bean方法主要是set方法,有Person类,Car类,Hello类他们都雷同,写一个就行了;

package com.atguigu.spring.beans;

public class Car {

    private double price;
private String color;
private String name;
public Car(double price, String color, String name) {
super();
this.price = price;
this.color = color;
this.name = name;
}
@Override
public String toString() {
return "Car [price=" + price + ", color=" + color + ", name=" + name
+ "]";
} }

在src目录下建立的main方法

package com.atguigu.spring.beans;

import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext; public class Main {
public static void main(String[] args) {
ApplicationContext cxt=new ClassPathXmlApplicationContext("applicationContext.xml"); Hello hello=(Hello) cxt.getBean("helloWorld");
hello.hello();
Car car=(Car) cxt.getBean("car");
System.out.println(car); Person person=(Person) cxt.getBean("person");
System.out.println(person);
}
}

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2.在配置文件中插入list和map集合,utli和 p 命名空间的使用,util适用于list集合,p简化代码;

其中person类中private list<Car> car; car属性是list集合泛型是Car;

person2类中private Map<Strng , Car> car;

DataSource类中只有private Properties properties;属性为文件类型,再设置get,set ,toStrong这类bean方法

  <bean id="car" class="com.atguigu.spring.beans2.Car">
<property name="name" value="changan"></property>
<property name="color" value="red"></property>
<property name="price" value="2312321"></property>
</bean> <bean id="car2" class="com.atguigu.spring.beans2.Car">
<property name="name" value="baoma"></property>
<property name="color" value="green"></property>
<property name="price" value="890"></property>
</bean> <bean id="person" class="com.atguigu.spring.beans2.Person">
<property name="name" value="panpan"></property>
<property name="age" value="21"></property>
<property name="car">
<list>
<ref bean="car"/>
<ref bean="car2"/>
</list>
</property>
</bean> <bean id="person2" class="com.atguigu.spring.beans2.Person">
<property name="name" value="jiajia"></property>
<property name="age" value="22"></property>
<property name="car">
<map>
<entry key="AAA" value-ref="car"></entry>
<entry key="BBB" value-ref="car2"></entry> </map>
</property>
</bean> <bean id="properties" class="com.atguigu.spring.beans2.DataSource">
<property name="properties">
<props>
<prop key="username">oraclejava</prop>
<prop key="password">lxn123</prop>
<prop key="jdbcUrl">oracle</prop>
<prop key="driverClass">drivaer</prop>
</props>
</property> </bean> <util:list id="cars">
<ref bean="car"/>
<ref bean="car2"/>
</util:list> <bean id="person3" class="com.atguigu.spring.beans2.Person">
<property name="name" value="panpan"></property>
<property name="age" value="12"></property>
<property name="car">
<ref bean="cars"/>
</property>
</bean>
<bean id="person4" class="com.atguigu.spring.beans2.Person"
p:name="quanquan" p:age="23" p:car-ref="cars">
  </bean>

Main类中的测试方法:

ApplicationContext app=new ClassPathXmlApplicationContext("applicationContext2.xml");

Person person=(Person) app.getBean("person");
System.out.println(person);

// Person person2=(Person) app.getBean("person2");
// System.out.println(person2);

DataSource dataSource=app.getBean(DataSource.class);
System.out.println(dataSource);

person=(Person) app.getBean("person3");
System.out.println(person);

person=(Person) app.getBean("person4");
System.out.println(person);

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bean的自动装配:使用时必须保证全类名下的i d名和 type具有唯一性;

通过类型:autowire="byType";

通过id名:autowire="byName"

<bean id="person" class="com.atguigu.spring.beans3.Person"
p:name="panpan" p:car-ref="car" p:address-ref="address">

</bean>

<bean id="person2" class="com.atguigu.spring.beans3.Person"
p:name="jiajia" autowire="byName">

</bean>

<bean id="person3" class="com.atguigu.spring.beans3.Person"
p:name="sjkdls" autowire="byType">

</bean>

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bean之间的关系:依赖和继承

继承:父类:abstract 必须设为 true,子类:有parent=”“;

依赖:通过depends-on 属性设定....

<bean id="address"
p:city="nanjing" p:street="jianjian" abstract="true">

</bean>

<bean id="address2" class="com.atguigu.spring.beans3.Address"
p:street="panpan" parent="address" >

</bean>

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通过bean的配置读取文件中数据,实现c3p0数据库连接池的链接

src目录下建立file文件jdbc.properties

user=root
password=lxn123
driverclass=com.mysql.jdbc.Driver
jdbcurl=jdbc:mysql:///test

spring 的bean文件applicationContext4.xml中进行配置;这里使用到了context命名空间

<!-- 使用外部的配置文件 -->
<context:property-placeholder location="classpath:jdbc.properties"/> <bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource">
<property name="user" value="${user}"></property>
<property name="password" value="${password}"></property>
<property name="driverClass" value="${driverclass}"></property>
<property name="jdbcUrl" value="${jdbcurl}"></property>
</bean>

Main类中测试:

ApplicationContext cx=new ClassPathXmlApplicationContext("applicationContext4.xml");
DataSource dataSource=(DataSource) cx.getBean("dataSource");
System.out.println(dataSource.getConnection());