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弹簧引导自动布线BeanCreationException for Static Field

spring-boot spring java

Robin · 技术社区 · 7 年前

当我自动连接我的属性类时,我遇到了一个问题。

下面是我的properties类,当我在@service类中自动连接它时,它的行为很好。

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.cloud.context.config.annotation.RefreshScope;
import org.springframework.core.env.Environment;
import org.springframework.stereotype.Component;

@Component
@RefreshScope
public class SMSHistoryProperties {

    @Autowired
    Environment env;

    /**
     * Return the property value associated with the given key, or null if the
     * key cannot be resolved.
     * 
     * @param propName
     * @return
     */ 
    public String getProperty(String propName){     
        return env.getProperty(propName);
    }

但是当我在我的sqlconstants类(它只有静态常量变量)中自动连接它时,我得到了一个异常。

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;

import com.vzw.onem.search.properties.SMSHistoryProperties;

@Component
public class SQLConstants {

    @Autowired
    private static SMSHistoryProperties prop;

    //~ Static fields/initializers ------------------------------------------

    private static final String SMS_SCHEMA = prop.getProperty("sms.schema");

我得到的例外情况如下:

org.springframework.beans.factory.BeanCreationException: Error
creating bean with name 'SQLConstants' defined in file
[...\SQLConstants.class]: Instantiation of bean failed; nested
exception is org.springframework.beans.BeanInstantiationException:
Failed to instantiate [com.search.constants.SQLConstants]: Constructor
threw exception; nested exception is java.lang.NullPointerException

编辑:

我取出了静态的最终引用,但仍然得到一个空指针异常。

@Autowired
private SMSHistoryProperties prop;

private String BATCH_SMS_SQL = "SELECT ACK_CODE FROM "
            + prop.getProperty("sms.schema");

这个 nullpointer 发生在 prop.getProperty("sms.schema") .

org.springframework.beans.factory.unsuspeedPendencyException:未满足的待处理异常: 创建名为“smscontroller”的bean时出错:依赖项不满意通过字段“smsbuilder”表示;嵌套异常为 org.springframework.beans.factory.unsuspeedPendencyException:未满足的待处理异常: 创建名为“smsbuilder”的bean时出错:不满足的依赖项通过字段“searchhelper”表示;嵌套异常为 org.springframework.beans.factory.unsuspeedPendencyException:未满足的待处理异常: 创建名为“smsjdbcsearchhelper”的bean时出错:未满足通过字段“cccdao”表示的依赖项;嵌套异常为 org.springframework.beans.factory.beanCreationException:错误正在创建文件中定义的名为“smssearchdaoimpl”的bean [..\smssearchdaoimpl.class]:bean的实例化失败;嵌套异常为org.springframework.beans.bean InstantiationException: 未能实例化[com.vzw.onem.search.dao.impl.smssearchdaoimpl]: 构造函数引发异常;嵌套异常为 java.lang.NullPointerException(空指针异常)

2 回复 | 直到 7 年前

davidxxx 7 年前

static

@PostConstruct

@Component
public class SQLConstants {

   @Autowired
   private SMSHistoryProperties prop;

   //~ Static fields/initializers ------------------------------------------

   private String SMS_SCHEMA; 

   @PostConstruct
   public void init(){
        SMS_SCHEMA = prop.getProperty("sms.schema"); 
   }
}

final

private final String schema;   

public SQLConstants(@Value("${sms.schema}")String schema){
    this.schema = schema;
}

@Value("${sms.schema}")
private String schema;

SMSHistoryProperties

@Component
@RefreshScope
public class SMSHistoryProperties {

    @Autowired
    Environment env;

    public String getSchema(){     
        return env.getProperty("sms.schema");
    }

    public String getOtherValue(){     
        return env.getProperty("sms.otherValue");
    }
}

Amit Bera 7 年前

Autowired Spring SMSHistoryProperties prop null prop getProperty("sms.schema"); NullPointerException