1、Instantiation with a Constructor（构造函数）
创建类DaoImpl1

package com.it.app.dao;
public class DaoImpl1 {private String name;private Integer age;public DaoImpl1(String name, Integer age){this.name = name;this.age = age;}public String getName() {return name;}public void setName(String name) {this.name = name;}public Integer getAge() {return age;}public void setAge(Integer age) {this.age = age;}@Overridepublic String toString() {return "DaoImpl1{" +"name='" + name + '\'' +", age=" + age +'}';}
}

spring-context.xml文件：daoImpl1

<?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="daoImpl1" class="com.it.app.dao.DaoImpl1"><constructor-arg name="name" value="micheal"></constructor-arg><constructor-arg name="age" value="12"></constructor-arg></bean>
</beans>

执行测试类：

package com.it.app;import com.it.app.dao.DaoImpl1;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;public class App {public static void main(String[] args) {ApplicationContext context = new ClassPathXmlApplicationContext("spring-context.xml");DaoImpl1 daoImpl1 = (DaoImpl1) context.getBean("daoImpl1");System.out.println(daoImpl1.toString());}
}

2、Instantiation with a Static Factory Method（通过静态工厂 Factory Method）：

package com.it.app.dao;public class DaoImpl2 {private static DaoImpl2 daoImpl2 = new DaoImpl2();private DaoImpl2(){}public static DaoImpl2 createDaoimpl2(){return daoImpl2;}
}

spring-context.xml文件：daoImpl2

<?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"><!--1、通过构造函数--><bean id="daoImpl1" class="com.it.app.dao.DaoImpl1"><constructor-arg name="name" value="micheal"></constructor-arg><constructor-arg name="age" value="12"></constructor-arg></bean><!--2、通过静态工厂--><bean id="daoImpl2" class="com.it.app.dao.DaoImpl2" factory-method="createDaoimpl2"></bean>
</beans>

执行测试代码：

package com.it.app;import com.it.app.dao.DaoImpl1;
import com.it.app.dao.DaoImpl2;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;public class App {public static void main(String[] args) {ApplicationContext context = new ClassPathXmlApplicationContext("spring-context.xml");DaoImpl2 daoImpl2 = (DaoImpl2) context.getBean("daoImpl2");System.out.println(daoImpl2.toString());}
}

3、Instantiation by Using an Instance Factory Method（实例化工厂）
创建DaoImpl3：

package com.it.app.dao;public class DaoImpl3 {private static DaoImpl3 daoImpl3 = new DaoImpl3();public DaoImpl3 createDaoImpl3(){return daoImpl3;}
}

spring-context.xml文件：

<?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"><!--1、通过构造函数--><bean id="daoImpl1" class="com.it.app.dao.DaoImpl1"><constructor-arg name="name" value="micheal"></constructor-arg><constructor-arg name="age" value="12"></constructor-arg></bean><!--2、通过静态工厂--><bean id="daoImpl2" class="com.it.app.dao.DaoImpl2" factory-method="createDaoimpl2"></bean><!--2、通过实例工厂--><bean id="daoImpl3" class="com.it.app.dao.DaoImpl3" ></bean><bean id="daoImpl3Factory" factory-bean="daoImpl3" factory-method="createDaoImpl3"></bean></beans>

执行测试类：

package com.it.app;import com.it.app.dao.DaoImpl1;
import com.it.app.dao.DaoImpl2;
import com.it.app.dao.DaoImpl3;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;public class App {public static void main(String[] args) {ApplicationContext context = new ClassPathXmlApplicationContext("spring-context.xml");DaoImpl3 daoImpl3 = (DaoImpl3) context.getBean("daoImpl3Factory");System.out.println(daoImpl3.toString());}
}