【Java Web開發學習】Spring4條件化的bean

轉載：https://www.cnblogs.com/yangchongxing/p/9071960.html

Spring4引入了@Conditional注解，可以用到帶有@Bean注解的地方，若給定的條件計算為true則創建bean，否則bean被忽略

用法：@Conditional(PlayerCondition.class)，設置為@Conditional注解的類必須是任意實現了org.springframework.context.annotation.Condition接口的類。該接口只有一個方法

public boolean matches(ConditionContext context, AnnotatedTypeMetadata matadata) {}，返回boolean

package cn.ycx.web.config;import org.springframework.context.annotation.Bean; import org.springframework.context.annotation.Conditional; import org.springframework.context.annotation.Configuration;import cn.ycx.web.model.Painter; import cn.ycx.web.model.PainterCondition; import cn.ycx.web.model.Player; import cn.ycx.web.model.PlayerCondition; @Configuration public class TestConfig {@Bean@Conditional(PlayerCondition.class)public Player player() {return new Player();}@Bean@Conditional(PainterCondition.class)public Painter painter() {return new Painter();} } package cn.ycx.web.model;import org.springframework.context.annotation.Condition; import org.springframework.context.annotation.ConditionContext; import org.springframework.core.env.Environment; import org.springframework.core.type.AnnotatedTypeMetadata;public class PlayerCondition implements Condition {@Overridepublic boolean matches(ConditionContext context, AnnotatedTypeMetadata matadata) {Environment env = context.getEnvironment();return env.containsProperty("CONDITION_PALY");} } package cn.ycx.web.model;import org.springframework.context.annotation.Condition; import org.springframework.context.annotation.ConditionContext; import org.springframework.core.env.Environment; import org.springframework.core.type.AnnotatedTypeMetadata;public class PainterCondition implements Condition {@Overridepublic boolean matches(ConditionContext context, AnnotatedTypeMetadata matadata) {Environment env = context.getEnvironment();return env.containsProperty("CONDITION_PAINT");} }

環境變量包含CONDITION_PALY就創建PlayerCondition

環境變量設置：

windows系統

spring.CONDITION_PALY=play

ubuntu系統

當前用戶

$ vim ~/.bashrc 追加 export CONDITION_PALY=play $ source ~/.bashrc

所有用戶

# vim /etc/profile 追加 export CONDITION_PALY=play # source /etc/profile

轉載于:https://www.cnblogs.com/yangchongxing/p/9071960.html

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