Spring框架浅入
SpringFramework概述及IOC
一：Spring概述、Spring体系介绍
Spring的核心是控制反转（IoC）和面向切面（AOP）
spring是开源的、轻量级的、一站式的框架，以 IoC（Inverse Of Control： 反转控制）和 AOP（Aspect Oriented Programming：面向切面编程）为内核
二：Spring安装配置
在工程目录下的pom.xml中配置
<dependency>
<groupId>org.springframeworkgroupId>
<artifactId>spring-contextartifactId>
<version>5.2.0.RELEASEversion>
dependency>
可在网上查找，粘贴过来
三：IOC
IOC容器初始化
ApplicationContext实现类
ApplicationContext是一个接口,有以下几个不同的实现类：
ClassPathXmlApplicationContext
AnnotationConfigApplicationContext
FileSystemXmlApplicationContext
XmlWebApplicationContext
ClassPathXmlApplicationContext
使用方法：
-
创建实体类
package com.lanou3g.bean; import lombok.Getter; import lombok.Setter; @Getter @Setter public class Man { private Food name; private String hobby; private int age; private String sex; private String food; public void eat(){ System.out.println("我叫" + name + ",我今年" + age + "岁了，我喜欢吃：" + food); } public void play(){ System.out.println("我叫" + name + ",我今年" + age + "岁了，我喜欢玩：" + hobby); } } -
配置Spring xml文件
<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 http://www.springframework.org/schema/beans/spring-beans.xsd"> <bean id="man" class="com.lanou3g.bean.Man"> <property name="age" value="18">property> <property name="food" value="橘子">property> <property name="hobby" value="吃鸡">property> <property name="name" ref="apple">property> <property name="sex" value="女">property> bean> <bean id="apple" class="com.lanou3g.bean.Food"> <property name="name" value="张飞">property> bean> beans> -
使用
public class App { public static void main( String[] args ) { useSpringIOC(); } public static void useSpringIOC(){ //加载Spring上下文配置文件 ApplicationContext cxt = new ClassPathXmlApplicationContext("applicationContext.xml"); //获取bean Man man = (Man) cxt.getBean("man"); Man man1 = cxt.getBean("man",Man.class); Man man2 = cxt.getBean(Man.class); man.eat(); man.play(); System.out.println("man:" + man); System.out.println("man1:" + man1); System.out.println("man2:" + man2); } }如果是两个xml文件以上，可以使用字符串数组
ApplicationContext cxt = new ClassPathXmlApplicationContext(new String[]{“applicationContext.xml”,“applicationContext1.xml”});
或者使用通配符
ApplicationContext cxt = new ClassPathXmlApplicationContext(“classpath:/*.xml”);
AnnotationConfigApplicationContext
使用方法:
-
创建实体类
package com.lanou3g.bean; import lombok.Getter; import lombok.Setter; @Getter @Setter public class Student { private String name; private int age; } -
创建@Configuration配置类
package com.lanou3g; import com.lanou3g.bean.Student; import org.springframework.context.annotation.Bean; import org.springframework.context.annotation.Configuration; @Configuration //表明是bean的配置类 public class AppConfig { @Bean public Student student1(){ //方法名相当于id Student student = new Student(); student.setName("张三"); student.setAge(18); return student; } @Bean public Student student2(){ Student student = new Student(); student.setName("赵云"); student.setAge(20); return student; } }@configuration可理解为用Spring的时候xml里面的标签
@Bean可理解为用Spring的时候xml里面的标签
-
使用
public class App { public static void main( String[] args ) { // useSpringIOC(); useSpringIOC2(); } public static void useSpringIOC2(){ AnnotationConfigApplicationContext ctx = new AnnotationConfigApplicationContext("AppConfig.class"); Student student1 = (Student) ctx.getBean("student1"); System.out.println(student1.getName()); System.out.println(student1.getAge()); Student student2 = (Student) ctx.getBean("student2"); System.out.println(student2.getName()); System.out.println(student2.getAge()); } }
FileSystemXmlApplicationContext
XmlWebApplicationContext
这两种跟上面的类似
Application初始化路径
路径前缀
// 前缀classpath：表示的是项目的classpath下相对路径
ApplicationContext ac = new ClassPathXmlApplicationContext("classpath:applicationContext.xml");
路径中的通配符
// 使用通配符加载所有符合要求的文件
ApplicationContext ac = new ClassPathXmlApplicationContext("classpath*:applicationContext.xml");
通过Xml方式配置管理bean
schema约束地址不能用https，否则每次都要从Spring加载，无网不能运行（新版本已解决这个问题）
使用步骤：
- 创建实体类
package com.lanou3g.bean;
import lombok.Getter;
import lombok.Setter;
@Getter
@Setter
public class Man {
private String hobby;
private int age;
private String sex;
private String food;
public void eat(){
System.out.println("我叫" + name + ",我今年" + age + "岁了，我喜欢吃：" + food);
}
public void play(){
System.out.println("我叫" + name + ",我今年" + age + "岁了，我喜欢玩：" + hobby);
}
}
- 配置xml
<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 http://www.springframework.org/schema/beans/spring-beans.xsd">
<bean id="man" class="com.lanou3g.bean.Man">
<property name="age" value="18">property>
<property name="food" value="橘子">property>
<property name="hobby" value="吃鸡">property>
<property name="name" ref="apple">property>
<property name="sex" value="女">property>
bean>
beans>
通过注解方式管理bean
两种方式：
第一种：
- 创建实体类
package com.lanou3g.bean;
import lombok.Getter;
import lombok.Setter;
import org.springframework.stereotype.Component;
@Component //把普通实体类实例化到spring容器中，相当于配置文件中的- 创建配置类
package com.lanou3g;
import com.lanou3g.bean.Student;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
@Configuration //表明该类是Spring的一个配置类，该类中会包含应用上下文创建bean的具体细节
@ComponentScan(basePackages = "com.lanou3g")//开启注解扫描支持，同时指定扫描包根路径
public class MyConfiguration {
}
- 使用
package com.lanou3g;
import com.lanou3g.bean.Student;
import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;
public class App {
public static void main( String[] args ) {
//加载Spring上下文配置文件
ApplicationContext cxt = new AnnotationConfigApplicationContext(MyConfiguration.class);
testIOCBean(cxt);
}
public static void testIOCBean(ApplicationContext cxt){
//获取bean
Student stu = cxt.getBean(Student.class);
System.out.println(stu.getName());
System.out.println(stu.getAge());
}
}
第二种：
- 创建实体类
package com.lanou3g.bean;
import lombok.Getter;
import lombok.Setter;
@Getter
@Setter
public class Student {
private String name;
private int age;
}
- 创建配置类
package com.lanou3g;
import com.lanou3g.bean.Student;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
//加上@Configuration注解后，这个类就相当于变成了一个Spring上下文配置文件
@Configuration
public class AppConfig {
@Bean
public Student student1(){
//方法名相当于id
Student student = new Student();
student.setName("张三");
student.setAge(18);
return student;
}
@Bean
public Student student2(){
Student student = new Student();
student.setName("赵云");
student.setAge(20);
return student;
}
}
@configuration可理解为用Spring的时候xml里面的标签
@Bean可理解为用Spring的时候xml里面的标签
- 使用
public class App {
public static void main( String[] args ) {
// useSpringIOC();
useSpringIOC2();
}
public static void useSpringIOC2(){
AnnotationConfigApplicationContext ctx = new AnnotationConfigApplicationContext("AppConfig.class");
Student student1 = (Student) ctx.getBean("student1");
System.out.println(student1.getName());
System.out.println(student1.getAge());
Student student2 = (Student) ctx.getBean("student2");
System.out.println(student2.getName());
System.out.println(student2.getAge());