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  • springBoot按条件装配:Condition

    编码格式转换器接口

    package com.boot.condition.bootconditionconfig.converter;
    
    /**
     * 编码格式转换器接口
     */
    public interface EncodingConverter {
    }

    GBK转换器

     

    package com.boot.condition.bootconditionconfig.converter;
    
    public class GBKEncodingConverter implements EncodingConverter {
    }

     

    UTF-8转换器

     

    package com.boot.condition.bootconditionconfig.converter;
    
    public class UTF8EncodingConverter implements EncodingConverter {
    }

     

    装配配置类

    package com.boot.condition.bootconditionconfig.config;
    
    import com.boot.condition.bootconditionconfig.condition.GBKCondition;
    import com.boot.condition.bootconditionconfig.condition.UTF8Condition;
    import com.boot.condition.bootconditionconfig.converter.EncodingConverter;
    import com.boot.condition.bootconditionconfig.converter.GBKEncodingConverter;
    import com.boot.condition.bootconditionconfig.converter.UTF8EncodingConverter;
    import org.springframework.boot.SpringBootConfiguration;
    import org.springframework.context.annotation.Bean;
    import org.springframework.context.annotation.Conditional;
    
    /**
     * 使用按照条件装配的过程:
     * 1、@Conditional [value值必须是实现Condition接口的类]
     * 2、根据接口中的matches方法的返回结果确定是否装配bean对象到spring容器中
     *    false 不装配 , true 就会装配到spring容器中
     */
    @SpringBootConfiguration
    // @Conditional(UTF8Condition.class)
    public class EncodingConverterConfig {
    
        @Bean
        @Conditional(UTF8Condition.class)
        public EncodingConverter createUTF8Converter() {
            return new UTF8EncodingConverter();
        }
    
        @Bean
        @Conditional(GBKCondition.class)
        public EncodingConverter createGBKConverter() {
            return new GBKEncodingConverter();
        }
    }

    GBK装配条件类

     

    package com.boot.condition.bootconditionconfig.condition;
    
    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 ("gbk".equals(encoding.toLowerCase())) {
                return true;
            }
            return false;
        }
    }

     

    UTF-8装配条件类

     

    package com.boot.condition.bootconditionconfig.condition;
    
    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 ("utf-8".equals(encoding.toLowerCase())) {
                return true;
            }
            return false;
        }
    }

     

    测试类

    package com.boot.condition.bootconditionconfig;
    
    import com.boot.condition.bootconditionconfig.converter.EncodingConverter;
    import org.springframework.boot.SpringApplication;
    import org.springframework.boot.autoconfigure.SpringBootApplication;
    import org.springframework.context.ConfigurableApplicationContext;
    
    import java.util.Map;
    
    @SpringBootApplication
    public class BootConditionConfigApplication {
    
    
        public static void main(String[] args) {
            ConfigurableApplicationContext context =
                    SpringApplication.run(BootConditionConfigApplication.class, args);
    
            Map<String, EncodingConverter> beansOfType = context.getBeansOfType(EncodingConverter.class);
            System.out.println(beansOfType);
            // 使用获取系统的编码格式的系统变量的key
            System.out.println(System.getProperty("file.encoding"));
    
            context.close();
        }
    }

    结果分析:

    file.encoding=’gbk’,则只装配GBKEncodingConverter

    file.encoding=’utf-8’,则只装配UTF8EncodingConverter

     

     

     

     

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  • 原文地址:https://www.cnblogs.com/lm970585581/p/9803965.html
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