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DI依赖注入和第三方bean管理以及核心容器
1.依赖注入方式
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setter 注入方式
- 简单类型
- 引用类型
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构造器注入
- 简单类型
- 引用类型
1.1 setter 注入简单类型
在实现类中添加简单数据类型，并提供 setter 方法
public class BookDaoImpl implements BookDao { //注入简单类型 private int num; public void setNum(int num) { this.num = num; } @Override public void save() { System.out.println("book dao save......"+num); } }- 1
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配置文件中添加 bean
<bean id="bookDao" class="com.my.dao.impl.BookDaoImpl"> <property name="num" value="10"/> bean>- 1
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测试运行结果
public static void main(String[] args) { ApplicationContext context=new ClassPathXmlApplicationContext("applicationConfig.xml"); BookDao bookDao = (BookDao) context.getBean("bookDao"); bookDao.save(); //book dao save......10 }- 1
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1.2 setter 注入引用数据类型
在实现类中添加引用数据类型，并提供 setter 方法
public class BookServiceImpl implements BookService { //注入引用类型 private BookDao bookDao; @Override public void save() { System.out.println("book service save......"); bookDao.save(); } //提供对应的set方法 public void setBookDao(BookDao bookDao) { this.bookDao = bookDao; } }- 1
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配置文件中添加 bean
<bean id="bookDao" class="com.my.dao.impl.BookDaoImpl"> <property name="connectionNum" value="10"/> bean> <bean id="bookService" class="com.my.service.impl.BookServiceImpl"> //引用类型 <property name="bookDao" ref="bookDao"/> bean>- 1
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测试运行结果
public static void main(String[] args) { ApplicationContext context=new ClassPathXmlApplicationContext("applicationConfig.xml"); BookService bookService = (BookService) context.getBean("bookService"); bookService.save(); //输出结果为： book service save...... //book dao save......10 }- 1
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1.3 构造器注入简单数据类型
在实现类中，添加构造方法
public class BookDaoImpl implements BookDao { private int num; public BookDaoImpl(int num) { this.num = num; } @Override public void save() { System.out.println("book dao save......"+num); } }- 1
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配置文件中配置 bean
<bean id="bookDao" class="com.my.dao.impl.BookDaoImpl"> <constructor-arg name="num" value="10"/> bean>- 1
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测试运行结果
public static void main(String[] args) { ApplicationContext context=new ClassPathXmlApplicationContext("applicationConfig.xml"); BookDao bookDao = (BookDao) context.getBean("bookDao"); bookDao.save(); //输出结果为：book dao save......10 } }- 1
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1.4构造器注入引用类型
在实现类中，添加构造方法
public class BookServiceImpl implements BookService { //注入引用类型 private BookDao bookDao; public BookServiceImpl(BookDao bookDao, UserDao userDao) { this.bookDao = bookDao; } @Override public void save() { System.out.println("book service save......"); bookDao.save(); } }- 1
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配置文件中配置 bean
<bean id="bookDao" class="com.my.dao.impl.BookDaoImpl"> <constructor-arg name="connectionNum" value="10"/> bean> <bean id="bookService" class="com.my.service.impl.BookServiceImpl"> <constructor-arg name="bookDao" ref="bookDao"/> bean>- 1
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测试运行结果
public static void main(String[] args) { ApplicationContext context=new ClassPathXmlApplicationContext("applicationConfig.xml"); BookService bookService = (BookService) context.getBean("bookService"); bookService.save(); //输出结果为：book service save...... //book dao save......10 }- 1
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1.5集合注入
创建一个实现类，添加集合：数组、List、Set、Map、Properties 。 并提供 setter 方法
public class BookDaoImpl implements BookDao { private int[] array; private List<String> list; private Set<String> set; private Map<String,String> map; private Properties properties; public void setArray(int[] array) { this.array = array; } public void setList(List<String> list) { this.list = list; } public void setSet(Set<String> set) { this.set = set; } public void setMap(Map<String, String> map) { this.map = map; } public void setProperties(Properties properties) { this.properties = properties; } @Override public void save() { System.out.println("array数组："+ Arrays.toString(array)); System.out.println("list数组："+list); System.out.println("set数组："+set); System.out.println("map数组："+map); System.out.println("properties数组："+properties); } }- 1
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配置文件，注入集合类型数据
<bean id="bookDao" class="com.my.dao.impl.BookDaoImpl"> <property name="array"> <array> <value>1value> <value>2value> <value>3value> array> property> <property name="list"> <list> <value>avalue> <value>bvalue> <value>cvalue> list> property> <property name="set"> <set> <value>avalue> <value>bvalue> <value>cvalue> <value>cvalue> set> property> <property name="map"> <map> <entry key="1" value="a"/> <entry key="2" value="b"/> <entry key="3" value="c"/> map> property> <property name="properties"> <props> <prop key="4">dprop> <prop key="5">eprop> <prop key="6">fprop> props> property> bean>- 1
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测试运行结果
public static void main(String[] args) { ApplicationContext context=new ClassPathXmlApplicationContext("applicationConfig.xml"); BookDao bookDao = (BookDao) context.getBean("bookDao"); bookDao.save(); //输出结果为：array数组：[1, 2, 3] //list数组：[a, b, c] //set数组：[a, b, c] //map数组：{1=a, 2=b, 3=c} //properties数组：{4=d, 5=e, 6=f} }- 1
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2. 第三方数据源对象管理（管理第三方 bean）
- 导入 spring-context 依赖和 第三方 Druid 依赖
<dependency> <groupId>org.springframeworkgroupId> <artifactId>spring-contextartifactId> <version>5.2.22.RELEASEversion> dependency> <dependency> <groupId>com.alibabagroupId> <artifactId>druidartifactId> <version>1.2.11version> dependency>- 1
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- 开启命名空间，在 beans 标签里添加 context ，如下：
<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 http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd ">- 1
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- 创建资源包 properties 文件
jdbc.driver=com.mysql.jdbc.Driver jdbc.url=jdbc:mysql://localhost:3306/spring jdbc.username=root jdbc.password=root- 1
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- 配置文件中加载 properties 文件，使用 ${} 读取文件里的属性值
<context:property-placeholder location="jdbc.properties"/> <bean id="dataSource" class="com.alibaba.druid.pool.DruidDataSource"> <property name="driverClassName" value="${jdbc.driver}"/> <property name="url" value="${jdbc.url}"/> <property name="username" value="${jdbc.username}"/> <property name="password" value="${jdbc.password}"/> bean>- 1
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测试运行结果
public static void main(String[] args) { ApplicationContext context =new ClassPathXmlApplicationContext("applicationConfig.xml"); DataSource dataSource = (DataSource) context.getBean("dataSource"); System.out.println(dataSource); //输出结果为：{ // CreateTime:"2022-09-18 19:45:03", // ActiveCount:0, // PoolingCount:0, // CreateCount:0, // DestroyCount:0, // CloseCount:0, // ConnectCount:0, // Connections:[ // ] //} }- 1
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3.核心容器
3.1创建容器的方式
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类路径加载配置文件
ApplicationContext context =new ClassPathXmlApplicationContext("applicationConfig.xml");- 1
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文件路径加载配置文件
ApplicationContext context1=new FileSystemXmlApplicationContext("D:\\SpringProjects\\spring_07_dataSource\\src\\main\\resources\\applicationConfig.xml");- 1
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加载多个配置文件，用逗号隔开
ApplicationContext context =new ClassPathXmlApplicationContext("applicationConfig.xml","applicationConfig2.xml");- 1
3.2获取 bean 的方式
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使用 bean 名称获取
BookDao bookDao = (BookDao) context.getBean("bookDao");- 1
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使用 bean 名称获取并指定类型
BookDao bookDao = context.getBean("bookDao", BookDao.class);- 1
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使用 bean 类型获取
BookDao bookDao = context.getBean(BookDao.class);- 1
3.3容器类层次结构
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- 原文地址：https://blog.csdn.net/m0_59564754/article/details/126922550
