Spring01

/**
 * 程序的耦合
 *      耦合：程序间的依赖关系
 *          包括：
 *              类之间的依赖
 *              方法间的依赖
 *      解耦：
 *          降低程序间的依赖关系
 *      实际开发中：
 *          应该做到：编译期不依赖，运行时才依赖。
 *      解耦的思路：
 *          第一步：使用反射来创建对象，而避免使用new关键字。
 *          第二步：通过读取配置文件来获取要创建的对象全限定类名
 *
 */
public class JdbcDemo1 {
    public static void main(String[] args) throws  Exception{
        //1.注册驱动
//        DriverManager.registerDriver(new com.mysql.jdbc.Driver());
        Class.forName("com.mysql.jdbc.Driver");

        //2.获取连接

package com.itheima.service;
//账户业务层的接口
public interface IAccountService {
//模拟保存账户
  void saveAccount();
}

//账户的业务层实现类
public class AccountServiceImpl implements IAccountService {

    private IAccountDao accountDao=new AccountDaoImpl();
    public void saveAccount() {
        accountDao.saveAccount();
    }
}

package com.itheima.dao;
 //账户的持久层接口
public interface IAccountDao {
    //模拟保存账户
    void saveAccount();
}

public class AccountDaoImpl implements IAccountDao {
    public void saveAccount() {
        System.out.println("保存了账户");
    }
}

//模拟一个表现层，用于调用持久层
public class Client {

    public static void main(String[] args) {
        IAccountService as = new AccountServiceImpl();
        as.saveAccount();
    }
}

/**
 * 一个创建Bean对象的工厂
 *
 * Bean：在计算机英语中，有可重用组件的含义。
 * JavaBean：用java语言编写的可重用组件。
 *      javabean >  实体类
 *
 *   它就是创建我们的service和dao对象的。
 *
 *   第一个：需要一个配置文件来配置我们的service和dao
 *           配置的内容：唯一标识=全限定类名（key=value)
 *   第二个：通过读取配置文件中配置的内容，反射创建对象
 *
 *   我的配置文件可以是xml也可以是properties

<?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
        https://www.springframework.org/schema/beans/spring-beans.xsd">
</beans>

<?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
        https://www.springframework.org/schema/beans/spring-beans.xsd">

    <!--把对象的创建交给spring来管理-->
    <bean id="accountService" class="com.itheima.service.impl.AccountServiceImpl"></bean>

    <bean id="accountDao" class="com.itheima.dao.impl.AccountDaoImpl"></bean>
</beans>

/**
 * 模拟一个表现层，用于调用持久层
 */
public class Client {

    public static void main(String[] args) {
        //IAccountService as = new AccountServiceImpl();
        //1、获取核心容器对象
        ApplicationContext ac = new ClassPathXmlApplicationContext("bean.xml");
        //2、根据id获取bean对象
        IAccountService as=(IAccountService) ac.getBean("accountService");
        IAccountDao ad=ac.getBean("accountDao",IAccountDao.class);
        System.out.println(as);
        System.out.println(ad);
    }
}

/**
 * 模拟一个工厂类（该类可能是存在于jar包中的，我们无法通过修改源码的方式来提供默认构造函数）
 */
public class InstanceFactory {

    public IAccountService getAccountService(){
        return new AccountServiceImpl();
    }
}

public class StaticFactory {

    public static IAccountService getAccountService(){

        return new AccountServiceImpl();
    }
}

ApplicationContext ac=new ClassPathXmlApplicationContext("bean.xml");
IAccountService as1=(IAccountService) ac.getBean("accountService");
IAccountService as2=(IAccountService) ac.getBean("accountService");
System.out.println(as1==as2);

public AccountServiceImpl() {
        System.out.println("对象创建了");
    }

<bean id="accountService" class="com.itheima.service.impl.AccountServiceImpl" scope="prototype"></bean>

<!--bean标签的scope属性-->
    <bean id="accountService" class="com.itheima.service.impl.AccountServiceImpl"
          scope="singleton" init-method="init" destroy-method="destroy"></bean>

package com.itheima.service.impl;

import com.itheima.service.IAccountService;

public class AccountServiceImpl implements IAccountService{

    public AccountServiceImpl() {
        System.out.println("对象创建了");
    }

    public void saveAccount() {
        System.out.println("service中的saveAccount方法执行了。。。");
    }

    public void init() {
        System.out.println("对象初始化了。。。");
    }
    public void destroy() {
        System.out.println("对象销毁了。。。");
    }
}

public class Client {

    public static void main(String[] args) {

        ApplicationContext ac=new ClassPathXmlApplicationContext("bean.xml");
        IAccountService as1=(IAccountService) ac.getBean("accountService");
        as1.saveAccount();
    }
}

为什么红了？多态，

public class AccountServiceImpl implements IAccountService{

    private String name;
    private Integer age;
    private Date birthday;

    public AccountServiceImpl(String name,Integer age,Date birthday) {
        this.name=name;
        this.age=age;
        this.birthday=birthday;
    }

    public void saveAccount() {
        System.out.println("service中的saveAccount方法执行了。。。"+name+","+age+","+birthday);
    }
}

<bean id="accountService" class="com.itheima.service.impl.AccountServiceImpl">
        <constructor-arg name="name" value="泰斯特"></constructor-arg>
        <constructor-arg name="age" value="18"></constructor-arg>
        <constructor-arg name="birthday" ref="now"></constructor-arg>
</bean>

<!-- 配置一个日期对象 -->
<bean id="now" class="java.util.Date"></bean>

<constructor-arg name="age" value="18"></constructor-arg>

public class AccountServiceImpl2 implements IAccountService{

    private String name;
    private Integer age;
    private Date birthday;

    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;
    }

    public Date getBirthday() {
        return birthday;
    }

    public void setBirthday(Date birthday) {
        this.birthday = birthday;
    }

    public void saveAccount() {
        System.out.println("service中的saveAccount方法执行了。。。"+name+","+age+","+birthday);
    }
}

public class AccountServiceImpl3 implements IAccountService{

    private String[] myStrs;
    private List<String> myList;
    private Set<String> mySet;
    private Map<String,String> myMap;
    private Properties myProps;

    public void setMyStrs(String[] myStrs) {
        this.myStrs = myStrs;
    }

    public void setMyList(List<String> myList) {
        this.myList = myList;
    }

    public void setMySet(Set<String> mySet) {
        this.mySet = mySet;
    }

    public void setMyMap(Map<String, String> myMap) {
        this.myMap = myMap;
    }

    public void setMyProps(Properties myProps) {
        this.myProps = myProps;
    }

    public void saveAccount() {
        System.out.println(Arrays.toString(myStrs));
        System.out.println(myList);
        System.out.println(mySet);
        System.out.println(myMap);
        System.out.println(myProps);
    }
}

    <bean id="accountService3" class="com.itheima.service.impl.AccountServiceImpl3">
        <property name="myStrs">
            <array>
                <value>AAA</value>
                <value>BBB</value>
                <value>CCC</value>
            </array>
        </property>
        <property name="myList">
            <list>
                <value>AAA</value>
                <value>BBB</value>
                <value>CCC</value>
            </list>
        </property>
        <property name="mySet">
            <set>
                <value>AAA</value>
                <value>BBB</value>
                <value>CCC</value>
            </set>
        </property>
        <property name="myMap">
            <map>
                <entry key="aaa" value="AAA"></entry>
                <entry key="bbb" value="BBB"></entry>
                <entry key="ccc">
                    <value>CCC</value>
                </entry>
            </map>
        </property>
        <property name="myProps">
            <props>
                <prop key="a">jack</prop>
                <prop key="b">robin</prop>
                <prop key="c">pony</prop>
            </props>
        </property>

    </bean>