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木舟0基础学习Java的第二十九天(Spring，Spring的属性注入(xml,注解))

news 来源：原创 2024/9/22 8:33:29

Spring(Spring FrameWork)

Spring是一个开源框架，最早由Rod Johnson发起 Spring为简化企业级开发而生使用Spring开发可以将Bean对象交给Spring容器来管理这样使得很多复杂的代码在Spring中开发会变得优雅简洁有效的降低代码的耦合度极大的方便项目的后期维护升级和扩展

官网:Https://spring.io

概述：

Spring是一个轻量级控制反转(IOC)和面向切面(AOP)为核心的容器框架

正转

Person.java

javac

→

Person.class

new

→

Person对象

第一个Spring程序（IOC案例）

<?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/beanshttps://www.springframework.org/schema/beans/spring-beans.xsd">
<!--下面这句话等同于 Users user=new User();告诉Spring这个com.spring.pojo.Users类交给你管理了--><bean id="user" class="com.spring.pojo.Users"></bean></beans>

@Data
public class Users implements Serializable {private int id;private String uname;private String pwd;
}

public class Demo {//控制正转的方式@Testpublic void run1(){Users user = new Users();user.setId(1);user.setUname("张三");user.setPwd("333");System.out.println(user);}//Spring中的控制反转技术(简称IOC技术)@Testpublic void run2(){//加载spring.xml配置文件ApplicationContext ac = new ClassPathXmlApplicationContext("spring.xml");//通过id从spring容器的对象缓存池中取bean(Users)对象//ac.getBean("user");//这时对象会被自动提升为Object对象 需要强转回来Users user =(Users) ac.getBean("user");user.setId(1);user.setUname("妮妮");user.setPwd("0105");System.out.println(user);}
}

基于xml映射文件中 bean标签的属性注入

@Data
public class Users implements Serializable {private int id;private String uname;private String pwd;//持有Clazz 引用数据类型private Clazz clazz;private Account account;
}

public class Clazz implements Serializable {
private String cname;
private int room;public Clazz() {}public Clazz(String cname, int room) {this.cname = cname;this.room = room;}public String getCname() {return cname;}public void setCname(String cname) {this.cname = cname;}public int getRoom() {return room;}public void setRoom(int room) {this.room = room;}@Overridepublic String toString() {return "Clazz{" +"cname='" + cname + '\'' +", room=" + room +'}';}
}

/*其他数据类型的注入*/
public class Data implements Serializable {private String[] arr;private List<Integer> list;private Set set;private Map map;private Properties properties;public Data() {}public Data(String[] arr, Properties properties, Map map, Set set, List<Integer> list) {this.arr = arr;this.properties = properties;this.map = map;this.set = set;this.list = list;}public String[] getArr() {return arr;}public void setArr(String[] arr) {this.arr = arr;}public List<Integer> getList() {return list;}public void setList(List<Integer> list) {this.list = list;}public Set getSet() {return set;}public void setSet(Set set) {this.set = set;}public Map getMap() {return map;}public void setMap(Map map) {this.map = map;}public Properties getProperties() {return properties;}public void setProperties(Properties properties) {this.properties = properties;}@Overridepublic String toString() {return "Data{" +"arr=" + Arrays.toString(arr) +", list=" + list +", set=" + set +", map=" + map +", properties=" + properties +'}';}
}

/*账户*/
public class Account {private int aid;private long money;public Account() {}public Account(int aid, long money) {this.aid = aid;this.money = money;}public int getAid() {return aid;}public void setAid(int aid) {this.aid = aid;}public long getMoney() {return money;}public void setMoney(long money) {this.money = money;}@Overridepublic String toString() {return "Account{" +"aid=" + aid +", money=" + money +'}';}
}

<?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/beanshttps://www.springframework.org/schema/beans/spring-beans.xsd"default-autowire="byName"
>
<!--全局自动注入↑  下面的每个bean都会自动注入--><!--下面这句话等同于 Users user=new User();告诉Spring这个com.spring.pojo.Users类交给你管理了--><bean id="user" class="com.spring.pojo.Users" scope="prototype"><!--scope="singleton"单态模式 默认是这个 从bean取出的对象为 同一 对象--><!--scope="prototype"原型模式 从bean取出的对象为 不同 对象--><!--这个标签不仅可以声明类 也可以给该类赋值--><property name="id" value="1"></property><property name="uname" value="小依"></property><!--等同于user.setUname("小依");--><property name="pwd" value="111"></property></bean>
<!--通过set方法给属性注入值--><bean id="clazz" class="com.spring.pojo.Clazz"><property name="cname" value="计算机应用科学"></property><property name="room" value="101"></property></bean><!--通过构造方法给属性注入值相当于new Clazz("英语",201)-->
<bean id="claz" class="com.spring.pojo.Clazz"><constructor-arg name="cname" value="英语"></constructor-arg><constructor-arg name="room" value="201"></constructor-arg>
</bean>
<!--给引用数据类型 持有的Clazz注入值--><bean id="user2" class="com.spring.pojo.Users" scope="prototype"><!--scope="singleton"单态模式 默认是这个 从bean取出的对象为 同一 对象--><!--scope="prototype"原型模式 从bean取出的对象为 不同 对象--><!--这个标签不仅可以声明类 也可以给该类赋值--><property name="id" value="2"></property><property name="uname" value="小贰"></property><property name="pwd"><value/></property><!--<value/>或者<null/>空值注入--><property name="clazz" ref="clazz"></property><!--ref="clazz"关联clazz--></bean><bean id="data" class="com.spring.pojo.Data"><property name="arr"><array><value>北京</value><value>上海</value><value>广州</value><value>深圳</value></array></property><property name="list"><list><value>10</value><value>20</value><value>30</value><value>40</value></list></property><property name="set"><set><value>庐山</value><value>衡山</value><value>华山</value><value>庐山</value></set></property><property name="map"><map><entry key="北京" value="010"></entry><entry key="广州" value="021"></entry><entry key="上海" value="020"></entry></map></property><property name="properties"><props><prop key="省会">奉天</prop><prop key="菜品">烧烤</prop><prop key="特色">洗浴</prop></props></property></bean>
<!--局部自动注入--><bean id="account" class="com.spring.pojo.Account"><property name="aid" value="11"></property><property name="money" value="12000"></property></bean><bean id="user3" class="com.spring.pojo.Users" scope="prototype" autowire="byType"><!--autowire=""自动注入--><!--autowire="byName"根据名字account自动注入 名字对应Users中持有的名称private Account account;--><!--autowire="byType"根据类型com.spring.pojo.Account自动注入 注意:不能同时有两个com.spring.pojo.Account--><property name="id" value="3"></property><property name="uname" value="小山"></property><property name="pwd" value="333"></property><property name="clazz" ref="clazz"></property><!--ref="clazz"关联clazz--></bean>
</beans>

基于注解的注入

<?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:context="http://www.springframework.org/schema/context"xsi:schemaLocation="http://www.springframework.org/schema/beans https://www.springframework.org/schema/beans/spring-beans.xsdhttp://www.springframework.org/schema/context https://www.springframework.org/schema/context/spring-context.xsd"><!-- bean definitions here --><!--以下的标签是在当前文件被加载之后，扫描指定的包下所有的实体类--><context:component-scan base-package="com.spring.pojo"></context:component-scan></beans>

@Component/*这个注解是告诉spring容器，当你扫描com.spring.pojo包下所有的实体类时
捕捉该@Component注解 将含有这个注解的类 加载到容器中 并创建对象。。。*/
/*该注解相当于 Users users=new Users(); 当前并没有指定该类名称 默认首字母小写为该类名称 users*/
/*@Component("u") 指定该类名称为u*/
//@Scope("singleton")//默认 指定该类为单例模式
@Scope("prototype")//指定该类为多例(原形)模式
public class Users implements Serializable {@Value("2")private int id;@Value("小贰")//给uname 赋值private String uname;@Value("222")private String pwd;//@Resource//引用类型的数据 根据bean的类型自动注入@Autowired//自动注入 同@Resource一样 建议使用private Clazz clazz;//@Qualifier//声明注入 根据指定的bean的名字自动注入 要与@Autowired搭配使用 建议不用@Resource//引用类型的数据 根据其类型自动注入private Account account;public Users() {}public Users(int id, String uname, String pwd, Clazz clazz, Account account) {this.id = id;this.uname = uname;this.pwd = pwd;this.clazz = clazz;this.account = account;}public int getId() {return id;}public void setId(int id) {this.id = id;}public String getUname() {return uname;}public void setUname(String uname) {this.uname = uname;}public String getPwd() {return pwd;}public void setPwd(String pwd) {this.pwd = pwd;}public Clazz getClazz() {return clazz;}public void setClazz(Clazz clazz) {this.clazz = clazz;}public Account getAccount() {return account;}public void setAccount(Account account) {this.account = account;}@Overridepublic String toString() {return "Users{" +"id=" + id +", uname='" + uname + '\'' +", pwd='" + pwd + '\'' +", clazz=" + clazz +", account=" + account +'}';}
}

/*账户*/
@Component(value = "account")//括号内的value可以省略
public class Account {@Value("101")private int aid;@Value("12000")private long money;public Account() {}public Account(int aid, long money) {this.aid = aid;this.money = money;}public int getAid() {return aid;}public void setAid(int aid) {this.aid = aid;}public long getMoney() {return money;}public void setMoney(long money) {this.money = money;}@Overridepublic String toString() {return "Account{" +"aid=" + aid +", money=" + money +'}';}
}

public class Demo {@Testpublic void run1(){ApplicationContext ca = new ClassPathXmlApplicationContext("Spring.xml");Users users =(Users) ca.getBean("users");users.setId(1);users.setUname("小依");users.setPwd("111");users.setClazz(new Clazz("计算机",101));users.setAccount(new Account(1,12000));System.out.println(users);}@Testpublic void run2(){ApplicationContext ca = new ClassPathXmlApplicationContext("Spring.xml");Users users =(Users) ca.getBean("users");System.out.println(users);}
}