spring(二)
一、为对象类型属性赋值
方式一:(引用外部bean)
1.创建班级类Clazz
package com.spring.bean
public class Clazz {
private Integer clazzId;
private String clazzName;
public Integer getClazzId() {
return clazzId;
}
public void setClazzId(Integer clazzId) {
this.clazzId = clazzId;
}
public String getClazzName() {
return clazzName;
}
public void setClazzName(String clazzName) {
this.clazzName = clazzName;
}
@Override
public String toString() {
return "Clazz{" +
"clazzId=" + clazzId +
", clazzName='" + clazzName + '\'' +
'}';
}
public Clazz() {
}
public Clazz(Integer clazzId, String clazzName) {
this.clazzId = clazzId;
this.clazzName = clazzName;
}
}
2.修改Student类
//在Student类中添加以下代码:
private Clazz clazz;
public Clazz getClazz() {
return clazz;
}
public void setClazz(Clazz clazz) {
this.clazz = clazz;
}
3.引用外部bean:
//配置Clazz类型的bean
<bean id="clazzOne" class="com.spring.bean.Clazz">
<property name="clazzId" value="001"></property>
<property name="clazzName" value="一般班"></property>
</bean>
//为Student中的clazz属性赋值
<bean id="studentFour" class="com.spring.bean.Student">
<property name="id" value="004"></property>
<property name="name" value="李寒衣"></property>
<property name="age" value="26"></property>
<property name="sex" value="女"></property>
<!-- ref属性:引用IOC容器中某个bean的id,将所对应的bean为属性赋值 -->
<property name="clazz" ref="clazzOne"></property>
</bean>
方式二:(内部bean)
<bean id="studentFour" class="com.spring.bean.Student">
<property name="id" value="1004"></property>
<property name="name" value="赵六"></property>
<property name="age" value="26"></property>
<property name="sex" value="女"></property>
<property name="clazz">
<!-- 在一个bean中再声明一个bean就是内部bean -->
<!-- 内部bean只能用于给属性赋值,不能在外部通过IOC容器获取,因此可以省略id属性 -->
<bean id="clazzInner" class="com.spring.bean.Clazz">
<property name="clazzId" value="002"></property>
<property name="clazzName" value="无心班"></property>
</bean>
</property>
</bean>
方式三:(级联属性赋值)
<bean id="studentFour" class="com.spring.bean.Student">
<property name="id" value="1004"></property>
<property name="name" value="赵六"></property>
<property name="age" value="26"></property>
<property name="sex" value="女"></property>
<property name="clazz" ref="clazzOne"></property>
<property name="clazz.clazzId" value="003"></property>
<property name="clazz.clazzName" value="天下第一班"></property>
</bean>
二、为数组类型属性赋值
1.在Student类中添加以下代码:
private String[] hobbies;
public String[] getHobbies() {
return hobbies;
}
public void setHobbies(String[] hobbies) {
this.hobbies = hobbies;
}
2.配置bean:
<bean id="studentFour" class="com.spring.bean.Student">
<property name="id" value="1004"></property>
<property name="name" value="赵六"></property>
<property name="age" value="26"></property>
<property name="sex" value="女"></property>
<!-- ref属性:引用IOC容器中某个bean的id,将所对应的bean为属性赋值 -->
<property name="clazz" ref="clazzOne"></property>
<property name="hobbies">
<array>
<value>抽烟</value>
<value>喝酒</value>
<value>烫头</value>
</array>
</property>
</bean>
三、为集合类型属性赋值
1.在clazz中添加以下代码:
private List<Student> students;
public List<Student> getStudents() {
return students;
}
public void setStudents(List<Student> students) {
this.students = students;
}
2.配置bean
<bean id="clazzTwo" class="com.spring.bean.Clazz">
<property name="clazzId" value="004"></property>
<property name="clazzName" value="Javaee"></property>
<property name="students">
<list>
<ref bean="studentOne"></ref>
<ref bean="studentTwo"></ref>
<ref bean="studentThree"></ref>
</list>
</property>
</bean>
<!--若为Set集合类型属性赋值,只需要将其中的list标签改为set标签即可-->
四、为Map集合类型属性赋值
1.创建教师类Teacher:
package com.spring.bean;
public class Teacher {
private Integer teacherId;
private String teacherName;
public Integer getTeacherId() {
return teacherId;
}
public void setTeacherId(Integer teacherId) {
this.teacherId = teacherId;
}
public String getTeacherName() {
return teacherName;
}
public void setTeacherName(String teacherName) {
this.teacherName = teacherName;
}
public Teacher(Integer teacherId, String teacherName) {
this.teacherId = teacherId;
this.teacherName = teacherName;
}
public Teacher() {
}
@Override
public String toString() {
return "Teacher{" +
"teacherId=" + teacherId +
", teacherName='" + teacherName + '\'' +
'}';
}
}
2.在Student类中添加以下代码:
private Map<String, Teacher> teacherMap;
public Map<String, Teacher> getTeacherMap() {
return teacherMap;
}
public void setTeacherMap(Map<String, Teacher> teacherMap) {
this.teacherMap = teacherMap;
}
3.配置bean:
<bean id="teacherOne" class="com.spring.bean.Teacher">
<property name="teacherId" value="10010"></property>
<property name="teacherName" value="沈眉庄"></property>
</bean>
<bean id="teacherTwo" class="com.atguigu.spring6.bean.Teacher">
<property name="teacherId" value="10086"></property>
<property name="teacherName" value="陆沉"></property>
</bean>
<bean id="studentFour" class="com.spring.bean.Student">
<property name="id" value="004"></property>
<property name="name" value="李寒衣"></property>
<property name="age" value="26"></property>
<property name="sex" value="女"></property>
<!-- ref属性:引用IOC容器中某个bean的id,将所对应的bean为属性赋值 -->
<property name="clazz" ref="clazzOne"></property>
<property name="hobbies">
<array>
<value>抽烟</value>
<value>喝酒</value>
<value>烫头</value>
</array>
</property>
<property name="teacherMap">
<map>
<entry>
<key>
<value>10010</value>
</key>
<ref bean="teacherOne"></ref>
</entry>
<entry>
<key>
<value>10086</value>
</key>
<ref bean="teacherTwo"></ref>
</entry>
</map>
</property>
</bean>
4.引用集合类型的bean
<!--list集合类型的bean-->
<util:list id="students">
<ref bean="studentOne"></ref>
<ref bean="studentTwo"></ref>
<ref bean="studentThree"></ref>
</util:list>
<!--map集合类型的bean-->
<util:map id="teacherMap">
<entry>
<key>
<value>10010</value>
</key>
<ref bean="teacherOne"></ref>
</entry>
<entry>
<key>
<value>10086</value>
</key>
<ref bean="teacherTwo"></ref>
</entry>
</util:map>
<bean id="clazzTwo" class="com.spring.bean.Clazz">
<property name="clazzId" value="004"></property>
<property name="clazzName" value="Javaee"></property>
<property name="students" ref="students"></property>
</bean>
<bean id="studentFour" class="com.pring.bean.Student">
<property name="id" value="004"></property>
<property name="name" value="李寒衣"></property>
<property name="age" value="26"></property>
<property name="sex" value="女"></property>
<!-- ref属性:引用IOC容器中某个bean的id,将所对应的bean为属性赋值 -->
<property name="clazz" ref="clazzOne"></property>
<property name="hobbies">
<array>
<value>抽烟</value>
<value>喝酒</value>
<value>烫头</value>
</array>
</property>
<property name="teacherMap" ref="teacherMap"></property>
</bean>
使用util:list、util:map标签必须引入相应的命名空间
<?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:util="http://www.springframework.org/schema/util"
xsi:schemaLocation="http://www.springframework.org/schema/util
http://www.springframework.org/schema/util/spring-util.xsd
http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans.xsd">
五、p命名空间
引入p命名空间
<?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:util="http://www.springframework.org/schema/util"
xmlns:p="http://www.springframework.org/schema/p"
xsi:schemaLocation="http://www.springframework.org/schema/util
http://www.springframework.org/schema/util/spring-util.xsd
http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans.xsd">
引入p命名空间后,可以通过以下方式为bean的各个属性赋值
<bean id="studentSix" class="com.spring.bean.Student"
p:id="006" p:name="小明" p:clazz-ref="clazzOne" p:teacherMap-ref="teacherMap"></bean>
六、引入外部属性文件
1.加入依赖
<!-- MySQL驱动 -->
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>8.0.30</version>
</dependency>
<!-- 数据源 -->
<dependency>
<groupId>com.alibaba</groupId>
<artifactId>druid</artifactId>
<version>1.2.15</version>
</dependency>
2.创建外部属性文件
<!--properties-->
jdbc.user=root
jdbc.password=root
jdbc.url=jdbc:mysql://localhost:3306/ssm?serverTimezone=UTC
jdbc.driver=com.mysql.cj.jdbc.Driver
3.引入属性文件
<!--xml-->
<!-- 引入外部属性文件 -->
<context:property-placeholder location="classpath:jdbc.properties"/>
4.配置bean
<bean id="druidDataSource" class="com.alibaba.druid.pool.DruidDataSource">
<property name="url" value="${jdbc.url}"/>
<property name="driverClassName" value="${jdbc.driver}"/>
<property name="username" value="${jdbc.user}"/>
<property name="password" value="${jdbc.password}"/>
</bean>
5.测试
@Test
public void testDataSource() throws SQLException {
ApplicationContext ac = new ClassPathXmlApplicationContext("spring-datasource.xml");
DataSource dataSource = ac.getBean(DataSource.class);
Connection connection = dataSource.getConnection();
System.out.println(connection);
}
七、bean的作用域
取值 | 含义 | 创建对象的时机 |
singleton(默认) | 在IOC容器中,这个bean的对象始终为单实例 | IOC容器初始化时 |
prototype | 这个bean在IOC容器中有多个实例 | 获取bean |
如果是在WebApplicationContext环境下还会有另外几个作用域(但不常用):
取值 | 含义 |
request | 在一个请求范围内有效 |
session | 在一个会话范围内有效 |
1、创建类User
package com.spring.bean;
public class User {
private Integer id;
private String username;
private String password;
private Integer age;
public User() {
}
public User(Integer id, String username, String password, Integer age) {
this.id = id;
this.username = username;
this.password = password;
this.age = age;
}
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getUsername() {
return username;
}
public void setUsername(String username) {
this.username = username;
}
public String getPassword() {
return password;
}
public void setPassword(String password) {
this.password = password;
}
public Integer getAge() {
return age;
}
public void setAge(Integer age) {
this.age = age;
}
@Override
public String toString() {
return "User{" +
"id=" + id +
", username='" + username + '\'' +
", password='" + password + '\'' +
", age=" + age +
'}';
}
}
2.配置bean
<!-- scope属性:取值singleton(默认值),bean在IOC容器中只有一个实例,IOC容器初始化时创建对象 -->
<!-- scope属性:取值prototype,bean在IOC容器中可以有多个实例,getBean()时创建对象 -->
<bean class="com.spring.bean.User" scope="prototype"></bean>
3.测试
@Test
public void testBeanScope(){
ApplicationContext ac = new ClassPathXmlApplicationContext("spring-scope.xml");
User user1 = ac.getBean(User.class);
User user2 = ac.getBean(User.class);
System.out.println(user1==user2);
}
八、bean生命周期
1.具体生命周期过程
- bean对象创建
- 给bean对象设置属性
- bean的后置处理器(初始化之前)
- bean对象初始化(需要在配置bean时指定初始化方法)
- bean的后置处理器(bean的后置处理器会在生命周期的初始化前后添加额外的操作,需要实现BeanPostProcessor接口,且配置到IOC容器中,需要注意的是,bean后置处理器不是单独针对某一个bean生效,而是针对IOC容器中所有bean都会执行)
- bean对象就绪可以使用
- bean对象销毁
- IOC容器关闭
九、FactoryBean
FactoryBean是Spring提供的一种整合第三方框架的常用机制。和普通bean不同,配置一个FactoryBean类型的bean,在获取bean的时候得到的并不是class属性中配置的这个类的对象,而是getObject()方法的返回值。通过这种机制,Spring可以帮我们把复杂组件创建的详细过程和繁琐细节都屏蔽起来,只把最简洁的使用界面展示给我们。
将来我们整合Mybatis时,Spring就是通过FactoryBean机制来帮我们创建SqlSessionFactory对象的。
1.创建类UserFactoryBean
package com.spring.bean;
public class UserFactoryBean implements FactoryBean<User> {
@Override
public User getObject() throws Exception {
return new User();
}
@Override
public Class<?> getObjectType() {
return User.class;
}
}
2.配置bean
<bean id="user" class="com.spring.bean.UserFactoryBean"></bean>
3.测试
@Test
public void testUserFactoryBean(){
//获取IOC容器
ApplicationContext ac = new ClassPathXmlApplicationContext("spring-factorybean.xml");
User user = (User) ac.getBean("user");
System.out.println(user);
}
原文地址:https://blog.csdn.net/weixin_73975059/article/details/140613132
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