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  • CheckStyle, 强制你遵循编码规范

    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>
    
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  • 原文地址:https://www.cnblogs.com/huang0925/p/3148389.html
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