使用 mysql-connector 时 buildscript 中的 ClassNotFoundException答案

【问题标题】：ClassNotFoundException in buildscript when using the mysql-connector使用 mysql-connector 时 buildscript 中的 ClassNotFoundException
【发布时间】：2017-03-19 17:06:55
【问题描述】：

当我从这个jooq plugin 运行generateTestDatabaseJooqSchema 任务时，我收到一个ClassNotFoundException 和消息java.lang.ClassNotFoundException: com.mysql.jdbc.Driver。我不知道为什么会这样，因为我在第 7 行的 buildscript 依赖项中包含了 mysql:mysql-connector-java:6.0.5。

buildscript {
    repositories {
        jcenter()
        mavenCentral()
    }
    dependencies {
        classpath 'mysql:mysql-connector-java:6.0.5'
        classpath 'nu.studer:gradle-jooq-plugin:2.0.0'
    }
}

plugins {
    id 'nu.studer.jooq' version '2.0.0'
    id 'org.flywaydb.flyway' version '4.0.3'
}

apply plugin: 'java'
apply plugin: 'idea'

// database connection information
def database_name = 'cloudpass-api'
def database_url = 'jdbc:mysql://localhost:3306/cloudpass-api'
def database_user = 'root'
def database_pass = 'password'

jooq {
    testDatabase(sourceSets.main) {
        jdbc {
            driver = 'com.mysql.jdbc.Driver'
            url = database_url
            user = database_user
            password = database_pass
            schema = database_name
        }
        generator {
            name = 'org.jooq.util.JavaGenerator'
            database {
                name = 'org.jooq.util.mysql.MySQLDatabase'
                inputSchema = database_name
            }
            generate {
                relations = true
                deprecated = false
                records = true
                immutablePojos = true
                fluentSetters = true
            }
            target {
                packageName = 'cloudpass.database'
            }
        }
    }
}

flyway {
    url = database_url
    user = database_user
    password = database_pass
}

repositories {
    jcenter()
    mavenCentral()
}

dependencies {
    compile 'org.slf4j:slf4j-api:1.7.21'
    compile 'mysql:mysql-connector-java:6.0.5'
    compile 'org.jooq:jooq'
    compile 'com.maxmind.geoip2:geoip2:2.8.0'
    testCompile 'junit:junit:4.12'
}

这是我运行任务时得到的完整输出：

C:\Users\Thomas\Projects\cloudpass-api-java>gradle generateTestDatabaseJooqSchemaSource
Starting a Gradle Daemon (subsequent builds will be faster)
:generateTestDatabaseJooqSchemaSource
nov. 06, 2016 7:54:15 AM org.jooq.tools.JooqLogger info
INFO: Initialising properties  : C:\Users\Thomas\Projects\cloudpass-api-java\build\tmp\jooq\config.xml
nov. 06, 2016 7:54:16 AM org.jooq.tools.JooqLogger error
SEVERE: Cannot read C:\Users\Thomas\Projects\cloudpass-api-java\build\tmp\jooq\config.xml. Error : com.mysql.jdbc.Driver
java.lang.ClassNotFoundException: com.mysql.jdbc.Driver
        at java.net.URLClassLoader.findClass(URLClassLoader.java:381)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
        at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:331)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
        at org.jooq.util.GenerationTool.loadClass(GenerationTool.java:591)
        at org.jooq.util.GenerationTool.run(GenerationTool.java:248)
        at org.jooq.util.GenerationTool.generate(GenerationTool.java:198)
        at org.jooq.util.GenerationTool.main(GenerationTool.java:170)

:generateTestDatabaseJooqSchemaSource FAILED

FAILURE: Build failed with an exception.

* What went wrong:
Execution failed for task ':generateTestDatabaseJooqSchemaSource'.
> Process 'command 'C:\Program Files\Java\jdk1.8.0_101\bin\java.exe'' finished with non-zero exit value -1

* Try:
Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output.

BUILD FAILED

Total time: 7.831 secs

我仍然对 gradle 不太满意，所以这可能是一个菜鸟问题，所以我很感谢你能提供的任何帮助。

【问题讨论】：

@Henry 我使用了apply plugin: 'nu.studer.jooq' 但是我仍然遇到同样的错误。
@Henry 这基本上是软件开发的座右铭

标签： gradle mysql-connector jooq build-script

【解决方案1】：

根据文档，这不起作用您需要将适当的数据库驱动器类放入特殊的jooqRuntime 配置：

根据您要连接的数据库，您需要将生成器类路径上的相应驱动程序。

dependencies { jooqRuntime 'postgresql:postgresql:9.1-901.jdbc4' }

【讨论】：