java在变量和方法名中使用下划线

Question

我对（命名约定）在变量名和方法名中使用下划线_作为起始字母感到困惑。例如_sampleVariable和_getUserContext()。谁能澄清一下什么时候使用它吗

Answer 1

通常在变量中使用u，将它们表示为类级私有变量

Answer 2

参见Java Naming Convetions

Except for variables, all instance, class, and class constants are in mixed case with a lowercase first letter. Internal words start with capital letters. Variable names should not start with underscore _ or dollar sign $ characters, even though both are allowed.

The names of variables declared class constants and of ANSI constants should be all uppercase with words separated by underscores ("_"). (ANSI constants should be avoided, for ease of debugging.)

Answer 3

通常不应使用，除非在所有大写常量中用作分隔符，这些大写常量通常是最终的（allStars但all_STARS）

正是因为通常不需要下划线，所以生成的代码中有大量的下划线。它也可以在一些旧代码中找到，这不是继续使用它的原因

Answer 4

引用罗伯特·C·马丁的《清洁代码》一书

Sometimes it is useful to warn other programmers about certain consequences.

范例

// Don't run unless you
// have some time to kill.
public void _testWithReallyBigFile() {
writeLinesToFile(10000000);
response.setBody(testFile);
response.readyToSend(this);
String responseString = output.toString(); assertSubString("Content-Length: 1000000000", responseString); assertTrue(bytesSent > 1000000000);
}

Nowadays, of course, we’d turn off the test case by using the @Ignore attribute with an appropriate explanatory string. @Ignore("Takes too long to run"). But back in the days before JUnit 4, putting an underscore in front of the method name was a common convention.

Answer 5

有时人们使用下划线来表示他们的变量或方法是私有的。我不喜欢这样做。我建议你也使用camelCase