Solve the problem:
在我们开发过程中总会遇到比如在线程中需要代用service或者mapper等读取数据库,或者某些自动注入bean失效的情况
problem analysis:
In the thread, because the thread is safe, it is impossible to automatically inject the bean
Solution:
1. Obtain the required beans through the tool class in the construction method
Tool class code:
import org.springframework.beans.BeansException;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;
import org.springframework.stereotype.Component;
/**
* @author yang
* @decription 通过工具类获取需要的的bean
*/
@Component
public class BeanContextUtils implements ApplicationContextAware {
/**
* 上下文对象实例
*/
private static ApplicationContext applicationContext;
@Override
public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
this.applicationContext = applicationContext;
}
/**
* 获取applicationContext
*
* @return
*/
public static ApplicationContext getApplicationContext() {
return applicationContext;
}
/**
* 通过name获取 Bean.
*
* @param name
* @return
*/
public static Object getBean(String name) {
return getApplicationContext().getBean(name);
}
/**
* 通过class获取Bean.
*
* @param clazz
* @param <T>
* @return
*/
public static <T> T getBean(Class<T> clazz) {
return getApplicationContext().getBean(clazz);
}
/**
* 通过name,以及Clazz返回指定的Bean
*
* @param name
* @param clazz
* @param <T>
* @return
*/
public static <T> T getBean(String name, Class<T> clazz) {
return getApplicationContext().getBean(name, clazz);
}
}
Test thread code:
public class TestThread implements Runnable {
private ISysUserService iSysUserService;
public TestThread(){
this.iSysUserService = BeanContextUtils.getBean(ISysUserService.class);
}
@Override
public void run() {
SysUser sysUser = iSysUserService.selectUserById(1l);
System.out.println("测试通过工具类获取bean 获取用户名 : {} "+sysUser.getUserName());
}
}
The calling thread executes:
TestThread testThread = new TestThread();
testThread.run();
Test Results:
Note: There is no need to add @Component, @Service and other annotations on the class
2. Inject the bean
test thread code through the set method:
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;
@Component
public class TestThread implements Runnable {
private static ISysUserService iSysUserService;
@Autowired
public void setISysUserService(ISysUserService iSysUserService){
TestThread.iSysUserService = iSysUserService;
}
@Override
public void run() {
SysUser sysUser = iSysUserService.selectUserById(1l);
System.out.println("测试通过set方法获取bean 获取用户名 : {} "+sysUser.getUserName());
}
}
Call code:
TestThread testThread = new TestThread();
testThread.run();
测试结果:
Note: @Component annotation needs to be added above the class
3. Call the bean test thread code in the class by statically initializing the execution class :
import javax.annotation.PostConstruct;
@Component
public class TestThread implements Runnable {
@Autowired
private ISysUserService iSysUserService;
//创建静态的线程类属性
private static TestThread testThread;
@PostConstruct
public void testThreadInit(){
System.out.println("执行成功");
testThread = this;
}
@Override
public void run() {
SysUser sysUser = this.testThread.iSysUserService.selectUserById(1l);
System.out.println("测试通过静态初始化执行类 获取bean 获取用户名 : {} "+sysUser.getUserName());
}
}
Call test:
TestThread testThread = new TestThread();
testThread.run();
Test Results:
4. Pass in through a parameterized construction method
Test thread code:
public class TestThread implements Runnable {
private ISysUserService iSysUserService;
public TestThread(ISysUserService iSysUserService){
this.iSysUserService = iSysUserService;
}
@Override
public void run() {
SysUser sysUser = iSysUserService.selectUserById(1l);
System.out.println("测试通过有参构造方法传入 获取bean 获取用户名 : {} "+sysUser.getUserName());
}
}
Call code:
//在引用类中自动注入bean或者其他方式注入bean
@Autowired
private ISysUserService iSysUserService;
//再引用方法中引用测试线程
TestThread testThread = new TestThread(iSysUserService);
testThread.run();
Test Results:
The personal test is available, and the above beans are created by yourself, so I won’t show examples here! ! !
There are also other bean injection methods here for reference.
Several other ways to inject beans