SpringBoot进阶教程(六十九)ApplicationContextAware

1. 添加实现ApplicationContextAware的工具类

package learn.utils;

import org.springframework.beans.BeansException;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;
import org.springframework.stereotype.Component;

/**
* @author toutou
* @date by 2020/12
* @des
*/
@Component
public class SpringContextUtil implements ApplicationContextAware {
private static ApplicationContext applicationContext;

@Override
public void setApplicationContext(ApplicationContext context) throws BeansException {
applicationContext = context;
}

public static ApplicationContext getApplicationContext() {
return applicationContext;
}
//获取Bean
public static <T> T getBean(
ad8
Class<T> requiredType){
return getApplicationContext().getBean(requiredType);
}
public static <T> T getBean(String name){
return (T) getApplicationContext().getBean(name);
}
}

2. 接口中直接调用

@GetMapping("home")
public Result getUser(){
UserAccountService userAccountService = SpringContextUtil.getBean(UserAccountService.class);
return Result.setSuccessResult(userAccountService.getUserAccountById(1));
}

3. service中内部调用

由于项目中配置了多个数据源，若所有mybatis mapper访问都集中在单个service方法中，@AutoDBDecision声明的数据源会串。所以需要颗粒化。这样就会在单个service中需要请求内部的方法，这时候也可以用上ApplicationContextAware工具类。

3.1 service中声明内部专用调用方法inside()

/**
* @author toutou
* @date by 2020/12
* des https://www.cnblogs.com/toutou/
*/
public interface UserAccountService {
default UserAccountService inside() {
return SpringContextUtil.getBean(UserAccountService.class);
}

UserAccountVO getUserAccountById(Integer id);

UserAccountVO getUserAccountById2(Integer id);
}

3.2 impl中调用方法

/**
* @author toutou
* @date by 2020/12
* des https://www.cnblogs.com/toutou/
*/
@Service
public class UserAccountServiceImpl implements UserAccountService{
@Autowired
UserAccountMapper userMapper;

public UserAccountVO getUserAccountById(Integer id){
UserAccountVO accountVO = null;
UserAccount account = userMapper.selectByPrimaryKey(id);
if (account != null) {
accountVO = new UserAccountVO();
accountVO.setId(account.getId());
accountVO.setAccount(account.getAccount());
accountVO.setAge(account.getAge());
accountVO.setEmail(account.getEmail());
accountVO.setUsername(account.getUsername());
accountVO.setPhone(account.getPhone());
}

return accountVO;
}

public UserAccountVO getUserAccountById2(Integer id){
return inside().getUserAccountById(id);
}
}

其他参考/学习资料：

• ApplicationContextAware (Spring Framework 5.3.2 API)
• How does ApplicationContextAware work in Spring?
• How to Get ApplicationContext in Spring Boot

v源码地址

https://github.com/toutouge/javademosecond/tree/master/hellolearn

作　　者：请叫我头头哥
出　　处：http://www.cnblogs.com/touto ad8 u/
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