CheckStyle插件

时间:2024-01-07 20:47:26

CheckStyle插件

如今代码静态检查越来越重要,已经成为构建高质量软件的不可或缺的一个验证步骤。如果你使用的是java语言,那么CheckStyle则是一个利器。 CheckStyle能够帮助程序员检查代码是否符合制定的规范。通过将CheckStyle的检查引入到项目构建中,可以强制让项目中的所有的开发者遵循制定规范,而不是仅仅停留在纸面上。如果发现代码违反了标准,比如类名未以大写开头、单个方法超过了指定行数、甚至单个方法抛出了3个以上的异常等。这些检查由于是基于源码的,所以不需要编译,执行速度快。

CheckStyle有针对不同IDE和构建工具的各种插件,方便开发者随时随地对代码进行静态检查。下面就讲解下如何将CheckStyle引入到maven构建中。

配置CheckStyle插件

在maven中一个名为maven-checkstyle-plugin的插件,用于执行CheckStyle task。下面是一个简单的配置。

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<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-checkstyle-plugin</artifactId>
<version>2.10</version>
<executions>
<execution>
<id>checkstyle</id>
<phase>validate</phase>
<goals>
<goal>check</goal>
</goals>
<configuration>
<failOnViolation>true</failOnViolation>
</configuration>
</execution>
</executions>
</plugin>

我们定义了在maven lifecycle的validate阶段执行check task,并且如果发现有违反标准的情况就会fail当前的build。

maven-checkstyle-plugin内置了4种规范.

  • config/sun_checks.xml
  • config/maven_checks.xml
  • config/turbine_checks.xml
  • config/avalon_checks.xml

其中sun_checks.xml为默认值。如果想要使用其他三种规范,则只需配置configuration。下面是使用maven_checks.xml的示例。

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<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-checkstyle-plugin</artifactId>
<version>2.10</version>
<configuration>
<configLocation>config/maven_checks.xml</configLocation>
</configuration>
<executions>
<execution>
<id>checkstyle</id>
<phase>validate</phase>
<goals>
<goal>check</goal>
</goals>
<configuration>
<failOnViolation>true</failOnViolation>
</configuration>
</execution>
</executions>
</plugin>

自定义规范文件

我们可以使用默认的规范未见,当然也支持自定义。下面是google的一个checkstyle规范文件。

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<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE module PUBLIC
"-//Puppy Crawl//DTD Check Configuration 1.3//EN"
"http://www.puppycrawl.com/dtds/configuration_1_3.dtd"> <!-- This is a checkstyle configuration file. For descriptions of
what the following rules do, please see the checkstyle configuration
page at http://checkstyle.sourceforge.net/config.html --> <module name="Checker"> <module name="RegexpSingleline">
<!-- Requires a Google copyright notice in each file.
Code intended to be open-sourced may have a multi-line copyright
notice, so that this required text appears on the second line:
<pre>
/*
* Copyright 2008 Google Inc.
*
* (details of open-source license...)
</pre>
-->
<property name="format"
value="^(//| \*) Copyright (\([cC]\) )?[\d]{4}(\-[\d]{4})? (Google Inc\.).*$" />
<property name="minimum" value="1" />
<property name="maximum" value="10" />
<property name="message" value="Google copyright is missing or malformed." />
<property name="severity" value="error" />
</module> <module name="FileTabCharacter">
<!-- Checks that there are no tab characters in the file.
-->
</module> <module name="NewlineAtEndOfFile"/> <module name="RegexpSingleline">
<!-- Checks that FIXME is not used in comments. TODO is preferred.
-->
<property name="format" value="((//.*)|(\*.*))FIXME" />
<property name="message" value='TODO is preferred to FIXME. e.g. "TODO(johndoe): Refactor when v2 is released."' />
</module> <module name="RegexpSingleline">
<!-- Checks that TODOs are named. (Actually, just that they are followed
by an open paren.)
-->
<property name="format" value="((//.*)|(\*.*))TODO[^(]" />
<property name="message" value='All TODOs should be named. e.g. "TODO(johndoe): Refactor when v2 is released."' />
</module> <!-- All Java AST specific tests live under TreeWalker module. -->
<module name="TreeWalker"> <!-- IMPORT CHECKS --> <module name="RedundantImport">
<!-- Checks for redundant import statements. -->
<property name="severity" value="error"/>
</module> <module name="ImportOrder">
<!-- Checks for out of order import statements. --> <property name="severity" value="warning"/>
<property name="groups" value="com.google,android,junit,net,org,java,javax"/>
<!-- This ensures that static imports go first. -->
<property name="option" value="top"/>
<property name="tokens" value="STATIC_IMPORT, IMPORT"/>
</module> <!-- JAVADOC CHECKS --> <!-- Checks for Javadoc comments. -->
<!-- See http://checkstyle.sf.net/config_javadoc.html -->
<module name="JavadocMethod">
<property name="scope" value="protected"/>
<property name="severity" value="warning"/>
<property name="allowMissingJavadoc" value="true"/>
<property name="allowMissingParamTags" value="true"/>
<property name="allowMissingReturnTag" value="true"/>
<property name="allowMissingThrowsTags" value="true"/>
<property name="allowThrowsTagsForSubclasses" value="true"/>
<property name="allowUndeclaredRTE" value="true"/>
</module> <module name="JavadocType">
<property name="scope" value="protected"/>
<property name="severity" value="error"/>
</module> <module name="JavadocStyle">
<property name="severity" value="warning"/>
</module> <!-- NAMING CHECKS --> <!-- Item 38 - Adhere to generally accepted naming conventions --> <module name="PackageName">
<!-- Validates identifiers for package names against the
supplied expression. -->
<!-- Here the default checkstyle rule restricts package name parts to
seven characters, this is not in line with common practice at Google.
-->
<property name="format" value="^[a-z]+(\.[a-z][a-z0-9]{1,})*$"/>
<property name="severity" value="warning"/>
</module> <module name="TypeNameCheck">
<!-- Validates static, final fields against the
expression "^[A-Z][a-zA-Z0-9]*$". -->
<metadata name="altname" value="TypeName"/>
<property name="severity" value="warning"/>
</module> <module name="ConstantNameCheck">
<!-- Validates non-private, static, final fields against the supplied
public/package final fields "^[A-Z][A-Z0-9]*(_[A-Z0-9]+)*$". -->
<metadata name="altname" value="ConstantName"/>
<property name="applyToPublic" value="true"/>
<property name="applyToProtected" value="true"/>
<property name="applyToPackage" value="true"/>
<property name="applyToPrivate" value="false"/>
<property name="format" value="^([A-Z][A-Z0-9]*(_[A-Z0-9]+)*|FLAG_.*)$"/>
<message key="name.invalidPattern"
value="Variable ''{0}'' should be in ALL_CAPS (if it is a constant) or be private (otherwise)."/>
<property name="severity" value="warning"/>
</module> <module name="StaticVariableNameCheck">
<!-- Validates static, non-final fields against the supplied
expression "^[a-z][a-zA-Z0-9]*_?$". -->
<metadata name="altname" value="StaticVariableName"/>
<property name="applyToPublic" value="true"/>
<property name="applyToProtected" value="true"/>
<property name="applyToPackage" value="true"/>
<property name="applyToPrivate" value="true"/>
<property name="format" value="^[a-z][a-zA-Z0-9]*_?$"/>
<property name="severity" value="warning"/>
</module> <module name="MemberNameCheck">
<!-- Validates non-static members against the supplied expression. -->
<metadata name="altname" value="MemberName"/>
<property name="applyToPublic" value="true"/>
<property name="applyToProtected" value="true"/>
<property name="applyToPackage" value="true"/>
<property name="applyToPrivate" value="true"/>
<property name="format" value="^[a-z][a-zA-Z0-9]*$"/>
<property name="severity" value="warning"/>
</module> <module name="MethodNameCheck">
<!-- Validates identifiers for method names. -->
<metadata name="altname" value="MethodName"/>
<property name="format" value="^[a-z][a-zA-Z0-9]*(_[a-zA-Z0-9]+)*$"/>
<property name="severity" value="warning"/>
</module> <module name="ParameterName">
<!-- Validates identifiers for method parameters against the
expression "^[a-z][a-zA-Z0-9]*$". -->
<property name="severity" value="warning"/>
</module> <module name="LocalFinalVariableName">
<!-- Validates identifiers for local final variables against the
expression "^[a-z][a-zA-Z0-9]*$". -->
<property name="severity" value="warning"/>
</module> <module name="LocalVariableName">
<!-- Validates identifiers for local variables against the
expression "^[a-z][a-zA-Z0-9]*$". -->
<property name="severity" value="warning"/>
</module> <!-- LENGTH and CODING CHECKS --> <module name="LineLength">
<!-- Checks if a line is too long. -->
<property name="max" value="${com.puppycrawl.tools.checkstyle.checks.sizes.LineLength.max}" default="100"/>
<property name="severity" value="error"/> <!--
The default ignore pattern exempts the following elements:
- import statements
- long URLs inside comments
--> <property name="ignorePattern"
value="${com.puppycrawl.tools.checkstyle.checks.sizes.LineLength.ignorePattern}"
default="^(package .*;\s*)|(import .*;\s*)|( *\* *https?://.*)$"/>
</module> <module name="LeftCurly">
<!-- Checks for placement of the left curly brace ('{'). -->
<property name="severity" value="warning"/>
</module> <module name="RightCurly">
<!-- Checks right curlies on CATCH, ELSE, and TRY blocks are on
the same line. e.g., the following example is fine:
<pre>
if {
...
} else
</pre>
-->
<!-- This next example is not fine:
<pre>
if {
...
}
else
</pre>
-->
<property name="option" value="same"/>
<property name="severity" value="warning"/>
</module> <!-- Checks for braces around if and else blocks -->
<module name="NeedBraces">
<property name="severity" value="warning"/>
<property name="tokens" value="LITERAL_IF, LITERAL_ELSE, LITERAL_FOR, LITERAL_WHILE, LITERAL_DO"/>
</module> <module name="UpperEll">
<!-- Checks that long constants are defined with an upper ell.-->
<property name="severity" value="error"/>
</module> <module name="FallThrough">
<!-- Warn about falling through to the next case statement. Similar to
javac -Xlint:fallthrough, but the check is suppressed if a single-line comment
on the last non-blank line preceding the fallen-into case contains 'fall through' (or
some other variants which we don't publicized to promote consistency).
-->
<property name="reliefPattern"
value="fall through|Fall through|fallthru|Fallthru|falls through|Falls through|fallthrough|Fallthrough|No break|NO break|no break|continue on"/>
<property name="severity" value="error"/>
</module> <!-- MODIFIERS CHECKS --> <module name="ModifierOrder">
<!-- Warn if modifier order is inconsistent with JLS3 8.1.1, 8.3.1, and
8.4.3. The prescribed order is:
public, protected, private, abstract, static, final, transient, volatile,
synchronized, native, strictfp
-->
</module> <!-- WHITESPACE CHECKS --> <module name="WhitespaceAround">
<!-- Checks that various tokens are surrounded by whitespace.
This includes most binary operators and keywords followed
by regular or curly braces.
-->
<property name="tokens" value="ASSIGN, BAND, BAND_ASSIGN, BOR,
BOR_ASSIGN, BSR, BSR_ASSIGN, BXOR, BXOR_ASSIGN, COLON, DIV, DIV_ASSIGN,
EQUAL, GE, GT, LAND, LE, LITERAL_CATCH, LITERAL_DO, LITERAL_ELSE,
LITERAL_FINALLY, LITERAL_FOR, LITERAL_IF, LITERAL_RETURN,
LITERAL_SYNCHRONIZED, LITERAL_TRY, LITERAL_WHILE, LOR, LT, MINUS,
MINUS_ASSIGN, MOD, MOD_ASSIGN, NOT_EQUAL, PLUS, PLUS_ASSIGN, QUESTION,
SL, SL_ASSIGN, SR_ASSIGN, STAR, STAR_ASSIGN"/>
<property name="severity" value="error"/>
</module> <module name="WhitespaceAfter">
<!-- Checks that commas, semicolons and typecasts are followed by
whitespace.
-->
<property name="tokens" value="COMMA, SEMI, TYPECAST"/>
</module> <module name="NoWhitespaceAfter">
<!-- Checks that there is no whitespace after various unary operators.
Linebreaks are allowed.
-->
<property name="tokens" value="BNOT, DEC, DOT, INC, LNOT, UNARY_MINUS,
UNARY_PLUS"/>
<property name="allowLineBreaks" value="true"/>
<property name="severity" value="error"/>
</module> <module name="NoWhitespaceBefore">
<!-- Checks that there is no whitespace before various unary operators.
Linebreaks are allowed.
-->
<property name="tokens" value="SEMI, DOT, POST_DEC, POST_INC"/>
<property name="allowLineBreaks" value="true"/>
<property name="severity" value="error"/>
</module> <module name="ParenPad">
<!-- Checks that there is no whitespace before close parens or after
open parens.
-->
<property name="severity" value="warning"/>
</module> </module>
</module>

如果想启用自定义的规范文件,则依旧是修改configuration,指向你的文件地址。

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        <plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-checkstyle-plugin</artifactId>
<version>2.10</version>
<configuration>
<configLocation>${basedir}/src/config/custom_checkstyle.xml</configLocation>
</configuration>
<executions>
<execution>
<id>checkstyle</id>
<phase>validate</phase>
<goals>
<goal>check</goal>
</goals>
<configuration>
<failOnViolation>true</failOnViolation>
</configuration>
</execution>
</executions>
</plugin>

运行checkstyle检查

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mvn checkstyle:checkstyle

查看checkstyle结果

运行maven命令后可以在console里查看checkstyle运行结果。

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[INFO]
[INFO] There are 11 checkstyle errors.
[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 2.135s
[INFO] Finished at: Fri Jun 21 13:39:24 CST 2013
[INFO] Final Memory: 6M/81M
[INFO] ------------------------------------------------------------------------
[ERROR] Failed to execute goal org.apache.maven.plugins:maven-checkstyle-plugin:2.10:check (checkstyle) on project SpringMessageSpike: You have 11 Checkstyle violations. -> [Help 1]

checkstye的详细结果信息被存放在target/checkstyle-result.xml中。下面是一个示例。

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<?xml version="1.0" encoding="UTF-8"?>
<checkstyle version="5.6">
<file name="/Users/twer/sourcecode/SpringMessageSpike/src/main/java/com/thoughtworks/config/SessionMessageSource.java">
<error line="0" severity="error" message="Google copyright is missing or malformed." source="com.puppycrawl.tools.checkstyle.checks.regexp.RegexpSinglelineCheck"/>
<error line="21" severity="warning" message="Wrong order for &apos;org.slf4j.LoggerFactory.getLogger&apos; import." source="com.puppycrawl.tools.checkstyle.checks.imports.ImportOrderCheck"/>
<error line="27" severity="error" message="Missing a Javadoc comment." source="com.puppycrawl.tools.checkstyle.checks.javadoc.JavadocTypeCheck"/>
<error line="35" severity="error" message="Line is longer than 100 characters (found 115)." source="com.puppycrawl.tools.checkstyle.checks.sizes.LineLengthCheck"/>
</file>
</checkstyle>

跳过对指定文件的某些检查

如果对于指定文件检查出了一些问题,但是你想忽略它,则可以使用suppression。

例如在上述例子中有一个checkstyle error是说某行超过了100字符。如果我们不想修复这个错误怎么办那?可以将其suppress掉。

方法是建立一个checkstyle-suppressions.xml文件。其中加入下述内容

checkstyle-suppressions.xml

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<?xml version="1.0"?>

<!DOCTYPE suppressions PUBLIC
"-//Puppy Crawl//DTD Suppressions 1.0//EN"
"http://www.puppycrawl.com/dtds/suppressions_1_0.dtd"> <suppressions>
<suppress checks="LineLengthCheck"
files="SessionMessageSource.java"
/>
</suppressions>

然后配置maven-checkstyel-plugin设置suppressionsLocation

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<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-checkstyle-plugin</artifactId>
<version>2.10</version>
<configuration>
<configLocation>${basedir}/src/config/custom_checkstyle.xml</configLocation>
<suppressionsLocation>${basedir}/src/config/checkstyle-suppressions.xml</suppressionsLocation>
</configuration>
<executions>
<execution>
<id>checkstyle</id>
<phase>validate</phase>
<goals>
<goal>check</goal>
</goals>
<configuration>
<failOnViolation>true</failOnViolation>
</configuration>
</execution>
</executions>
</plugin>