Spring4 根据类型自动装配属性类型为java.util.Properties

Question

1.配置文件：

<bean id="person4" class=".." autowire="byType" />

<util:properties id="propertiesReader" location="classpath:yuan.properties" /> 

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2.相关代码

    public class Person{
        private Properties props;
    
        @Value("#{propertiesReader[username}")
        public void setProps(Properties props) {
            this.props = props;
        }
        //..
    }

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3.尝试解决的方案：

1.<util:properties id="propertiesReader" location="classpath:test.properties" />

2、在类中需要注入的属性实现 setter 和 getter 方法。

3、在 setter 方法前，添加 @Value 注解

@Value ("#{propertiesReader[propertiesName]}")

propertiesName 为 properties 文件中的键。这样，在容器启动过程中， Spring 将自动注入值。

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4.异常信息（说找到2个.properties 文件）：org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'person4' defined in class path resource [beans.xml]: Unsatisfied dependency expressed through bean property 'props': : No qualifying bean of type [java.util.Properties] is defined: expected single matching bean but found 2: propertiesReader,systemProperties; nested exception is org.springframework.beans.factory.NoUniqueBeanDefinitionException: No qualifying bean of type [java.util.Properties] is defined: expected single matching bean but found 2: propertiesReader,systemProperties

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5.控制台：

信息: Loading properties file from class path resource [yuan.properties]（从类路径资源加载属性文件[yuan.properties]）

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Answer 1

不需要 get set 方法

@Value("#{propertiesReader}")
public Properties props;

@Value("#{propertiesReader['username']}")
public String username;

Answer 2

既然你要注入的是整个 properties，那么应该写的是：

@Value("#{propertiesReader}")
public void setProps(Properties props) {
    this.props = props;
}

而不是

@Value("#{propertiesReader[username]}")