第二章 通過實例瞭解Spring IOC

一、通過Bean類型從IOC容器中獲取Bean實例

<code>
<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>
​
        <property>
        <property>
        <property>
    /<bean>
    
    <bean>
        <property>
    /<bean>
/<beans>/<code>

<code>package com.bigdata.test;
​
import com.bigdata.spring.Person;
import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
​
public class PersonTest {
​
    /**
     * 實驗2：根據Bean的類型從IOC容器中獲取Bean的實例
     * 如果ioc容器中這個類型的bean有多個，查找就會報錯。
     */
    @Test
    public void testGetPersonBean() {
        ApplicationContext ioc = new ClassPathXmlApplicationContext("ioc.xml");
        Person person = ioc.getBean(Person.class);
        System.out.println(person);
​
        Person person02 = ioc.getBean("person02", Person.class);
        System.out.println(person02); 

    }
}
​/<code>

二、通過構造器為Bean的屬性賦值

1、在Person類中創建有參和無參構造器

<code>package com.bigdata.spring;
​
public class Person {
    private String lastName;
    private int age;
    private String email;
​
    public Person() {
        super();
        System.out.println("無參構造器被調用了");
    }
​
    public Person(String lastName, int age, String email) {
        super();
        this.lastName = lastName;
        this.age = age;
        this.email = email;
        System.out.println("#########有參構造器被調用了###########");
    }
​
    public String getLastName() {
        return lastName;
    }
​
    public void setLastName(String lastName) {
        this.lastName = lastName;
    }
​
    public int getAge() {
        return age;
    }
​
    public void setAge(int age) {
        this.age = age;
    } 

​
    public String getEmail() {
        return email;
    }
​
    public void setEmail(String email) {
        this.email = email;
    }
​
    @Override
    public String toString() {
        return "Person{" +
                "lastName='" + lastName + '\\'' +
                ", age=" + age +
                ", email='" + email + '\\'' +
                '}';
    }
}
​/<code>

2、在ioc.xml文件中配置有參注入方法

<code>
<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>
​
        <property>
        <property>
        <property>
    /<bean>
​
    <bean>
        <property>
    /<bean>
​
    
    <bean>
         

        <constructor-arg>
        <constructor-arg>
        <constructor-arg>
    /<bean>
/<beans>/<code>

3、測試參數構造器給Bean屬性賦值

<code>    @Test
    public void testGetPersonBean() {
        ApplicationContext ioc = new ClassPathXmlApplicationContext("ioc.xml");
//        Person person = ioc.getBean(Person.class);
//        System.out.println(person);
​
        Person person02 = ioc.getBean("person02", Person.class);
        System.out.println(person02);
​
        Person person03 = ioc.getBean("person03", Person.class);
        System.out.println(person03);
    }/<code>

三、通過有參構造器給Bean屬性賦值index type

1、在ioc.xml添加配置信息

<code>     
<bean>
        
        <constructor-arg>
        <constructor-arg>
        <constructor-arg>
    /<bean>/<code>

2、測試有參構造器給Bean屬性賦值--index type

<code>    @Test
    public void testGetPersonBean() {
        ApplicationContext ioc = new ClassPathXmlApplicationContext("ioc.xml");
//        Person person = ioc.getBean(Person.class);
//        System.out.println(person);
​
//        Person person02 = ioc.getBean("person02", Person.class);
//        System.out.println(person02);
//
//        Person person03 = ioc.getBean("person03", Person.class);
//        System.out.println(person03);
​
        Person person04 = ioc.getBean("person04", Person.class);
        System.out.println(person04);
    }/<code>

四、通過P命名空間為Bean賦值

1、在ioc.xml文件中添加p標籤

<code>
<beans>       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:context="http://www.springframework.org/schema/context"
       xmlns:p="http://www.springframework.org/schema/p"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd">
​
    
    <bean>
​
    /<bean>
/<beans>/<code>

2、在PersonTest.java中添加測試方法

<code>    @Test
    public void testGetPersonBean() {
        ApplicationContext ioc = new ClassPathXmlApplicationContext("ioc.xml");
//        Person person = ioc.getBean(Person.class);
//        System.out.println(person);
​
//        Person person02 = ioc.getBean("person02", Person.class);
//        System.out.println(person02);
//
//        Person person03 = ioc.getBean("person03", Person.class);
//        System.out.println(person03);
​
//        Person person04 = ioc.getBean("person04", Person.class);
//        System.out.println(person04);
​
        Person person05 = ioc.getBean("person05", Person.class);
        System.out.println(person05); 

    }/<code>

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