public static void main(String[] args) {
ApplicationContext context=new ClassPathXmlApplicationContext("applicationContext.xml");
DBSpringDao bean = context.getBean(DBSpringDao.class);
//BeanFactory factory = context;
//DBSpringDao bean = factory.getBean(DBSpringDao.class);
String sql="select * from i_user";
List<Map<String, Object>> list=bean.queryForList(sql);
}
擷取Bean的其他方式
注意 ClassPathXmlApplicationContext 和 FileSystemXmlApplicationContext 的差別
// 用classpath路徑,不加classpath預設字首
ApplicationContext context = new ClassPathXmlApplicationContext("classpath:applicationContext.xml");
ApplicationContext context = new ClassPathXmlApplicationContext("applicationContext.xml");
// ClassPathXmlApplicationContext使用了file字首是可以使用絕對路徑的
ApplicationContext context = new ClassPathXmlApplicationContext("file:F:/workspace/project/src/applicationContext.xml");
// 用檔案系統的路徑,預設指項目的根路徑
ApplicationContext context = new FileSystemXmlApplicationContext("src/applicationContext.xml");
ApplicationContext context = new FileSystemXmlApplicationContext("webRoot/WEB-INF/applicationContext.xml");
// 使用了classpath:字首,這樣,FileSystemXmlApplicationContext也能夠讀取classpath下的相對路徑
ApplicationContext context = new FileSystemXmlApplicationContext("classpath:applicationContext.xml");
ApplicationContext context = new FileSystemXmlApplicationContext("file:F:/workspace/project/src/applicationContext.xml");
// 不加file字首
ApplicationContext context = new FileSystemXmlApplicationContext("F:/workspace/project/src/applicationContext.xml");
為了避免重新裝載applicationContext.xml并執行個體化上下文bean不用類似
new ClassPathXmlApplicationContext()的方式,從已有的spring上下文取得已執行個體化的bean。
首先建立一個工具類
//實作ApplicationContextAware
public class ApplicationContextUtil implements ApplicationContextAware {
private ApplicationContext context;//聲明一個靜态變量
@Override
public void setApplicationContext(ApplicationContext applicationContext)
throws BeansException {
this.context=applicationContext;
}
public ApplicationContext getContext(){
return context;
}
}
注入
springboot使用注解進行注入
//初始化并注入
<bean id="applicationContextUtil" class="com.service.utils.ApplicationContextUtil"></bean>
//業務類進行注入applicationContextUtil執行個體
<bean id="xxxx" class="com.service.xx.xx.xx" >
<property name="appContextUtil" ref="applicationContextUtil" />
</bean>
使用
ApplicationContext context=appContextUtil.getContext();
DBSpringDao bean = context.getBean(DBSpringDao.class);
String sql="select * from i_user";
List<Map<String, Object>> list=bean.queryForList(sql);