整合 IOC创建对象

创建对象的方式：

• 无参构造函数创建对象
  
• 带参数的构造函数创建对象
  • 一般参数
  • 参数是其他类的对象
  • 参数是集合类型
    
• 工厂创建对象
  
  • 静态方法创建对象
    
  • 非静态方法创建对象

示例工程：

代码：

applicationContext.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"
    xmlns:p="http://www.springframework.org/schema/p"
    xmlns:context="http://www.springframework.org/schema/context"
    xsi:schemaLocation="
        http://www.springframework.org/schema/beans
        http://www.springframework.org/schema/beans/spring-beans.xsd
        http://www.springframework.org/schema/context
        http://www.springframework.org/schema/context/spring-context.xsd">
    <!--
        使用bean节点来创建对象
        id属性标识着对象
        name属性代表着要创建对象的类全名
    -->
    <bean id="user" class="com.bean.User"/>
    <bean id="person" class="com.bean.Person"/>
    <bean id="userWithParams" class="com.bean.User">
        <!-- 通过constructor这个节点来指定构造函数的参数类型、名称、第几个 -->
        <constructor-arg index="0" name="id" type="java.lang.String" value="1"></constructor-arg>
        <constructor-arg index="1" name="username" type="java.lang.String" value="yue"></constructor-arg>
        <!-- 如果参数是对象，需要用ref引用 -->
          <constructor-arg index="2" name="person" type="com.bean.Person" ref="person"></constructor-arg>
    </bean>
      <!-- 工厂静态方法创建对象  -->
    <bean id="userByFactory" class="com.factory.Factory" factory-method="getBeanByStatic" >
    </bean>
      <!-- 工厂非静态方法创建对象 -->
    <bean id="factory" class="com.factory.Factory"/>
    <bean id="userByFactory2" class="com.bean.User" factory-bean="factory" factory-method="getBean" >
    </bean>
      <!-- 参数为集合 -->
         <bean id="personWithParams" class="com.bean.Person">
                <property name="lists">
            <list>
                <value>list1</value>
                <value>list2</value>
                <value>list3</value>
            </list>
        </property>
        <property name="sets">
            <set>
                <value>set1</value>
                <value>set2</value>
                <value>set3</value>
            </set>
        </property>
        <property name="maps">
            <map>
                <entry key="1" value="map1" />
                <entry key="2" value="map2" />
            </map>
        </property>
    </bean>
</beans>

User.java

package com.bean;
public class User {
    private String id;
    private String username;
    private Person person;
    public User() {}
    public User(String id, String username, Person person) {
        this.id = id;
        this.username = username;
        this.person = person;
    }
    public String getId() {
        return id;
    }
    public void setId(String id) {
        this.id = id;
    }
    public String getUsername() {
        return username;
    }
    public void setUsername(String username) {
        this.username = username;
    }
    public Person getPerson() {
        return person;
    }
    public void setPerson(Person person) {
        this.person = person;
    }
}

Person.java

package com.bean;
import java.util.List;
import java.util.Map;
import java.util.Set;
public class Person {
    public String personID = "1";
    private List<String> lists;
    private Set<String> sets;
    private Map<String, String> maps;
    public Person() {}
    public Person(String personID, List<String> lists) {
        this.personID = personID;
        this.setLists(lists);
    }
    public Map<String, String> getMaps() {
        return maps;
    }
    public void setMaps(Map<String, String> maps) {
        this.maps = maps;
    }
    public Set<String> getSets() {
        return sets;
    }
    public void setSets(Set<String> sets) {
        this.sets = sets;
    }
    public List<String> getLists() {
        return lists;
    }
    public void setLists(List<String> lists) {
        this.lists = lists;
    }
}

Factory.java

package com.factory;
import com.bean.User;
public class Factory {
    public static User getBeanByStatic() {
        return new User();
    }
    public User getBean() {
        return new User();
    }
}

TestMain.java

package com.main;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import com.bean.User;
public class TestMain {
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        ApplicationContext ac = new ClassPathXmlApplicationContext("applicationContext.xml");
        User user = (User)ac.getBean("user");
        User user2 = (User)ac.getBean("userWithParams");
        System.out.println(user);
        System.out.println(user2);
        System.out.println(user2.getUsername());
        System.out.println(user2.getPerson().personID);
        User user3 = (User)ac.getBean("userByFactory");
        System.out.println(user3);
        User user4 = (User)ac.getBean("userByFactory2");
        System.out.println(user4);
        Person person = (Person)ac.getBean("personWithParams");
        for (String list: person.getLists()) {
            System.out.println(list);
        }
        for (String set: person.getSets()) {
            System.out.println(set);
        }
        for (Entry<String, String> entry: person.getMaps().entrySet()) {
            System.out.println(entry);
        }
    }
}

运行结果：