基于SpringIOC创建对象的四种方式总结

package com.MLXH.pojo;
public class User {
    private String name;
    private String sex;
    private int age;
    public User() {
        System.out.println("User的无参构造");
    }
    public User(String name) {
        System.out.println("User的有参构造");
        this.name = name;
    }
    public User(String name, int age) {
        System.out.println("User的第二种有参构造");
        this.name = name;
        this.age = age;
    }
    public User(String name, String sex, int age) {
        System.out.println("User的第三种有参构造");
        this.name = name;
        this.sex = sex;
        this.age = age;
    }
    public void setName(String name) {
        System.out.println(name);
        this.name = name;
    }
    public void setAge(int age) {
        this.age = age;
    }
    @Override
    public String toString() {
        return "User{" +
                "name='" + name + '\'' +
                ", age=" + age +
                '}';
    }
}

<?xml version="1.0" encoding="UTF-8"?>
<!--suppress SpringFacetInspection -->
<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">
	<!--无参构造-->
	<bean id="user" class="com.MLXH.pojo.User">
    </bean>
    <!--无参构造,执行set方法-->
    <bean id="user1" class="com.MLXH.pojo.User">
        <property name="name" value="寒雪1"/>
    </bean>
    <!--使用构造器的参数下标进行赋值-->
    <bean id="user2" class="com.MLXH.pojo.User">
        <constructor-arg index="0" value="寒雪2"/>
        <constructor-arg index="1" value="18"/>
    </bean>
    <!--通过名字进行赋值-->
    <bean id="user3" class="com.MLXH.pojo.User">
        <constructor-arg name="name" value="寒雪3"/>
        <constructor-arg name="age" value="3"/>
    </bean>
    <!--通过类型进行赋值-->
    <bean id="user4" class="com.MLXH.pojo.User">
        <constructor-arg type="java.lang.String" value="寒雪4"/>
        <constructor-arg type="java.lang.Integer" value="18"/>
        <constructor-arg type="java.lang.String" value="男"/>
    </bean>
</beans>

package com.MLXH.pojo;
import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
public class UserTest {
    @Test
    public void test1(){
        ApplicationContext context = new ClassPathXmlApplicationContext("beans.xml");
        User user = (User)context.getBean("user1");
        System.out.println(user.toString());
    }
    @Test
    public void test2(){
        ApplicationContext context = new ClassPathXmlApplicationContext("beans.xml");
        User user = (User) context.getBean("user2");
        System.out.println(user);
    }
    @Test
    public void test3(){
        ApplicationContext context = new ClassPathXmlApplicationContext("beans.xml");
        User user = (User) context.getBean("user3");
        System.out.println(user);
    }
}

ApplicationContext context = new ClassPathXmlApplicationContext("beans.xml");

<bean id="user1" class="com.MLXH.pojo.User">
        <property name="name" value="寒雪1"/>
</bean>

User user1 = new User();
user1.setName="寒雪1";

//启动spring容器(根据Spring配置文件不同创建不同的Spring容器)
ApplicationContextcontext =
newClassPathXmlApplicationContext(
"resources/spring_ioc.xml");

Class.forName(“com.spring.ioc.Hello”).newInstance()

//从spring容器中获取对象hello
Hello hello = (Hello)context.getBean("Hello");
//使用hello对象调用sayHello方法
hello.sayHello();

        package staticfactory;
        import java.util.Calendar;
        public class StaticFactory {
               public static Calendar getCalendar(){
                      return Calendar.getInstance();
               }
         }

<bean id="cal" class="staticfactory.StaticFactory" factory-method="getCalendar"/>

@Test
publicvoid test2(){
      //启动spring容器
     ApplicationContextcontext =
     newClassPathXmlApplicationContext("staticfactory/applicationContext.xml");
     Calendar calendar = (Calendar)context.getBean("cal");
     System.out.println(calendar.getTime());
}

package methodfactory;
import java.util.Calendar;
public class MethodFactory {
       publicMethodFactory() {
      System.out.println("如果创建工厂类的实例，必定会打印这句话！");
       }
       publicCalendar getCalendar(){
      returnCalendar.getInstance();
       }
}

<bean id="methodFacotry" class="methodfactory.MethodFactory"/>
<bean id="cal" factory-bean="methodFacotry"  factory-method="getCalendar"/>

@Test
public void test(){
//启动spring容器
ApplicationContext context =
newClassPathXmlApplicationContext("methodfactory/applicationContext.xml");
Calendar calendar = (Calendar)context.getBean("cal");
System.out.println(calendar.getTime());
}

package springfactory;
import java.util.Calendar;
import org.springframework.beans.factory.FactoryBean;
public class SpringFactory implements FactoryBean<Calendar>{
public SpringFactory() {
System.out.println("我是一个spring工厂类");
}
               
public Calendar getObject()throws Exception {
return Calendar.getInstance();
}
               
public Class<?> getObjectType() {
return Calendar.class;
}
               
public boolean isSingleton() {
return false;
}
}

<bean id="cal"class="springfactory.SpringFactory"/>

@Test
public void test3(){
//启动spring容器
ApplicationContext context =
newClassPathXmlApplicationContext("springfactory/applicationContext.xml");
Calendar calendar = (Calendar)context.getBean("cal");
System.out.println(calendar.getTime());
}

 
<bean id="Hello" class="com.spring.ioc.Hello"scope="prototype"/>

<bean id="Hello"class="com.spring.ioc.Hello" scope="singleton"lazy-init="true"/>