java - 记录对象哈希码有用吗？

Question

我在接手的项目中看到了很多这样的行:

log.debug(submitObject(" + object + ")");
log.debug(registerUser(" + user + ")");

等等。

在日志中打印出如下内容:

SubmitObject(java.lang.Object@13a317a)

仅记录对象类型及其哈希码是否有用？假设我想知道用户对象的名称，但我只有哈希码，我是否可以根据哈希码重建对象？

来自 object.toString() 的 javadoc

Returns a string representation of the object. In general, the toString method returns a string that "textually represents" this object. The result should be a concise but informative representation that is easy for a person to read. It is recommended that all subclasses override this method. The toString method for class Object returns a string consisting of the name of the class of which the object is an instance, the at-sign character `@', and the unsigned hexadecimal representation of the hash code of the object. In other words, this method returns a string equal to the value of:

getClass().getName() + '@' + Integer.toHexString(hashCode())
Returns: a string representation of the object.

我自己总是覆盖自定义对象的 toString() 以便它打印出对象的所有字段。我应该改为打印目标代码吗？

Answer 1

您可以使用 org.apache.commons 中的 ReflectionToStringBuilder，如果您无权访问源代码，或者如果您不想实现 toString 以更改现有代码.

例如:


如果 (LOGGER.isDebugEnabled()) {

 LOGGER.debug("用户:"
    + reflectionToStringBuilder.toString(用户，
         ToStringStyle.MULTI_LINE_STYLE))

}


"LOGGER.isDebugEnabled() 非常重要，因为 toString 操作或 reflectionToStringBuilder 将在调用 log.debug 之前执行，因此您不希望进行如此昂贵的操作.

ReflectionToStringBuilderJavaDoc:http://commons.apache.org/proper/commons-lang/javadocs/api-2.6/org/apache/commons/lang/builder/ReflectionToStringBuilder.html