spring boot 的conditioanal的解析
一：
package com.zcp.springstart2;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.ConfigurableApplicationContext;
@SpringBootApplication
public class App {
public static void main(String[] args) {
ConfigurableApplicationContext context = SpringApplication.run(App.class, args);
System.out.println(System.getProperty("file.encoding"));
System.out.println(context.getBeansOfType(EncodingConvert.class));
System.out.println(">>>>>>>>>>>>>start>>>>>>>>>>>>");
System.out.println(context.getBeansOfType(Runnable.class));
System.out.println(">>>>>>>>>>>>>end>>>>>>>>>>>>");
context.close();
}
}
接口：
package com.zcp.springstart2;
public interface EncodingConvert {
}
接口的实现:
package com.zcp.springstart2;
public class UTF8EncodingConvert implements EncodingConvert {
}
package com.zcp.springstart2;
public class GBKEncodingConvert implements EncodingConvert {
}
package com.zcp.springstart2;
import org.springframework.context.annotation.Condition;
import org.springframework.context.annotation.ConditionContext;
import org.springframework.core.type.AnnotatedTypeMetadata;
public class GBKCondition implements Condition {
@Override
public boolean matches(ConditionContext context, AnnotatedTypeMetadata metadata) {
String encoding = System.getProperty("file.encoding");
if(null != encoding){
return "gbk".equals(encoding.toLowerCase());
}
return false;
}
}
package com.zcp.springstart2;
import org.springframework.context.annotation.Condition;
import org.springframework.context.annotation.ConditionContext;
import org.springframework.core.type.AnnotatedTypeMetadata;
public class UTF8Condition implements Condition {
@Override
public boolean matches(ConditionContext context, AnnotatedTypeMetadata metadata) {
String encoding = System.getProperty("file.encoding");
if(null != encoding){
return "utf-8".equals(encoding.toLowerCase());
}
return false;
}
}
常用的conditional的使用:
package com.zcp.springstart2;
import org.springframework.boot.SpringBootConfiguration;
import org.springframework.boot.autoconfigure.condition.ConditionalOnBean;
import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;
import org.springframework.context.annotation.Bean;
@SpringBootConfiguration
public class UserConfig {
@Bean
@ConditionalOnProperty(name="runnable.enabled",havingValue="true",matchIfMissing=true)
public Runnable createRunnable(){
return new Runnable() {
@Override
public void run() {
System.out.println("UserConfig中的Runnable");
}
};
}
@Bean
@ConditionalOnClass(name="com.zcp.springstart2.User")
public Runnable createRunnableOnClass(){
return new Runnable() {
@Override
public void run() {
System.out.println("UserConfig中的createRunnableOnBean");
}
};
}
@Bean
@ConditionalOnBean(name="user")
public Runnable createRunnableOnBean(){
return new Runnable() {
@Override
public void run() {
System.out.println("UserConfig中的createRunnableOnBean");
}
};
}
}
