一.使用注解@Configuration
1.创建实体Author.class：
public class Author { private String firstName; private String lastName; public Author() { super(); // TODO Auto-generated constructor stub System.out.println("Author constructor"); } //省略 setter, getter }
2.创建配置AppConfig.class：
@Configuration//告诉ApplicationContext这个类定义了bean public class AppConfig { @Bean public Author author1() { return new Author(); } }
3.创建Main.class，读取配置：
public class Main { public static void main(String[] args) { AnnotationConfigApplicationContext context = new AnnotationConfigApplicationContext(AppConfig.class);//读取AppConfig Author author = (Author) context.getBean("author1");//获取方法名为author1的bean System.out.println(author); } }
4.控制台输出：
Author constructor说明在初始化的时候spring读取配置并调用@bean注解的方法author1，返回new Author并创建了实体Author，在构造函数处打印输出
5.源码地址：https://github.com/Jamie956/simpleSpring/tree/master/01-configBean
二.使用XML
1.创建实体Employee.class：
public class Employee { private String name; public void displayName() { System.out.println(name); } //省略setter, getter }
2.创建配置文件beans.xml：
<?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 http://www.springframework.org/schema/beans/spring-beans-4.3.xsd"> <bean id="employee" class="com.example.Employee"> <property name="name" value="test spring"></property> </bean> </beans>id：当我们读取beans.xml时，就是靠id来找到这个bean
class：就是这个bean代表的实体
property：给这个bean的name变量赋值“test spring”
3.创建Main.class读取配置：
public class Main { public static void main(String[] args) { ApplicationContext context = new ClassPathXmlApplicationContext("beans.xml");//读取beans.xml Employee employee = (Employee) context.getBean("employee");//获取id为employee的bean employee.displayName();//调用employee的方法 } }
4.控制台输出：
test spring
5.源码地址：https://github.com/Jamie956/simpleSpring/tree/master/01-xmlBean
三.使用注解@Component
1.创建实体Author.class：
@Component//能让applicationcontext扫描到 public class Author { private String firstName = "Steven"; private String lastName = "King"; //省略setter, getter }
2.读取配置：
public class Main { public static void main(String[] args) { AnnotationConfigApplicationContext context = new AnnotationConfigApplicationContext(); context.scan("com.example");//扫描com.example包下包含@component注解的类 context.refresh(); Author author = context.getBean(Author.class); System.out.println(author); } }
3.控制输出：
com.example.entity.Author@4e7dc304说明Author已经创建
源码地址： https://github.com/Jamie956/simpleSpring/tree/master/01-annotationBean
转载于:https://www.cnblogs.com/jamie956/p/9017145.html
