我要评论applicationcontext的三个常用实现类
filesystemxmlapplicationcontext：可以加载磁盘路径下的配置文件(不常用)
public class client {
public static void main(string[] args) {
applicationcontext context =
new filesystemxmlapplicationcontext("c:\\users\\ghh\\desktop\\bean.xml");
accountservice service = context.getbean("accountservice", accountservice.class);
accountdao accountdao = context.getbean("accountdao", accountdao.class);
system.out.println(service);
system.out.println(accountdao);
}
}
classpathxmlapplicationcontext：可以加载类路径下的配置文件
要求配置文件必须在类路径下面
public class client {
public static void main(string[] args) {
applicationcontext context =
new classpathxmlapplicationcontext("bean.xml");
accountservice service = context.getbean("accountservice", accountservice.class);
accountdao accountdao = context.getbean("accountdao", accountdao.class);
system.out.println(service);
system.out.println(accountdao);
}
}
annotationconfigapplicationcontext：读取注解创建容器
applicationcontext=null的问题
问题
要对一个公共模块项目，进行一个拆分，做一个细化。
调整的时候，调整了启单类的位置（并未注意到），单元测试的时候，就报错。
import org.springframework.beans.beansexception;
import org.springframework.context.applicationcontext;
import org.springframework.context.applicationcontextaware;
import org.springframework.stereotype.component;
@component
public class springutils implements applicationcontextaware {
private static applicationcontext applicationcontext;
@override
public void setapplicationcontext(applicationcontext applicationcontext) throws beansexception {
springutils.applicationcontext = applicationcontext;
}
public static applicationcontext getapplicationcontext() {
return applicationcontext;
}
public static object getbean(string name) {
return applicationcontext.getbean(name);
}
public static <t> t getbean(class<t> requiredtype) {
return applicationcontext.getbean(requiredtype);
}
}setapplicationcontext 调试的时候，方法没进去。说明bean没有初始化。
处理1：检查目录
启动类要在顶层的位置，这样才会读整个，就不用设置@componentscan
处理2：设置@componentscan
指定具体读取的路径
@componentscan(basepackages = {"com.basic.common"})
public class basiccommonapplication {
public static void main(string[] args) {
springapplication.run(basiccommonapplication.class, args);
}
@bean
public dozerbeanmapperfactorybean dozerbeanmapperfactorybean() {
return new dozerbeanmapperfactorybean();
}
}心得：
如果在单个项目中，启动类需要在顶层的位置，才不用设置@componentscan，否则需要进行设置，才能读取得到。
总结
以上为个人经验，希望能给大家一个参考，也希望大家多多支持代码网。
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