增量任务与最新状态检查
声明输入和输出，让 Gradle 跳过已经是最新状态的工作，从而使自定义任务快速且正确。
增量任务与最新状态检查 是 CoddyKit 上的免费 Groovy & Gradle: JVM Automation and Build Engineering 课时。 这是第 4 节课，共 4 节。 你可以在下方免费阅读本课时的完整内容 — 然后在浏览器中使用内置代码编辑器和全天候 AI 导师进行实践。 这是 Groovy & Gradle: JVM Automation and Build Engineering 学习路径的一部分，你的进度在网页和 CoddyKit 应用中同步。 Groovy & Gradle: JVM Automation and Build Engineering 课程共包含 4 节课。
本课时的部分内容尚未翻译，以英文显示。
Why Tasks Get Skipped
Gradle is fast because it does not redo work. If a task ran before and nothing it depends on changed, Gradle marks it UP-TO-DATE and skips it. You enable this by declaring inputs and outputs.
Inputs and Outputs
Every task can declare what it reads (inputs) and what it produces (outputs). Gradle hashes them to decide whether to run.
Declaring File Inputs
Annotate or register input files so Gradle watches them for changes.
tasks.register('process') {
inputs.file 'data/in.txt'
outputs.file 'build/out.txt'
}The Up-to-Date Decision
On each run Gradle compares current input/output hashes to the last run. If both match, the task is skipped; if any input changed, it re-runs.
Property Inputs
Non-file inputs (a flag, a version string) are declared with inputs.property so changing them also invalidates the cache.
tasks.register('gen') {
inputs.property 'version', project.version
outputs.dir 'build/gen'
}Custom Task Types
For reusable logic, write a task class with annotated properties: @InputFile, @OutputFile, @Input. Gradle reads the annotations automatically.
An Annotated Task Class
Annotations tell Gradle how to track each property without manual inputs/outputs wiring.
class Copy extends DefaultTask {
@InputFile File source
@OutputFile File dest
@TaskAction void run() { dest.text = source.text }
}Incremental Inputs
For tasks over many files, @Incremental inputs let the action process only the files that actually changed since last run.
The Build Cache
Beyond up-to-date checks, the build cache can reuse outputs from a previous run on any machine, keyed by the same input hashes — huge for CI.
org.gradle.caching=trueCommon Mistakes
Forgetting to declare an input is the classic bug: Gradle skips a task that should have re-run, producing stale output. Always declare every input that affects the result.
Forcing a Rerun
To verify caching or work around a stale state, run with --rerun-tasks to ignore up-to-date checks for one build, or use outputs.upToDateWhen { false } to mark a task as never up to date.
gradle build --rerun-tasksQuick Check
Test your incremental build knowledge.
Recap
You learned to build fast, correct tasks:
- Gradle skips tasks whose inputs and outputs are unchanged
- Declare files with
inputs.file/outputs.fileand values withinputs.property - Custom task classes use
@InputFile/@OutputFileannotations - The build cache reuses outputs across machines
- Undeclared inputs cause stale, incorrect skips
常见问题解答
「增量任务与最新状态检查」课时是免费的吗？
是的 — 「增量任务与最新状态检查」的完整文本可在网页上免费阅读。要进行交互式练习（内置代码编辑器和全天候 AI 导师）并解锁 Groovy & Gradle: JVM Automation and Build Engineering 课程的其余内容，请升级到 CoddyKit PRO。 Groovy & Gradle: JVM Automation and Build Engineering 课程共包含 4 节课。
「增量任务与最新状态检查」这节课中我会学到什么？
声明输入和输出，让 Gradle 跳过已经是最新状态的工作，从而使自定义任务快速且正确。 你通过在浏览器中直接运行的动手代码来练习 Groovy & Gradle: JVM Automation and Build Engineering，全天候 AI 导师会在你学习这节课的过程中回答你的问题。
学习 Groovy & Gradle: JVM Automation and Build Engineering 需要有经验吗？
无需任何先前经验。CoddyKit 上的 Groovy & Gradle: JVM Automation and Build Engineering 课程适合初学者到高级学习者，你可以从这里开始或从头开始，按照自己的节奏学习。 这是第 4 节课，共 4 节。
「增量任务与最新状态检查」课时需要多长时间？
大多数 CoddyKit 课程大约需要 5–10 分钟。每节课都很精短且互动，所以你能稳步进步，并在网页和应用中从离开的地方继续。
我能在这节 Groovy & Gradle: JVM Automation and Build Engineering 课中编写并运行代码吗？
能。每节 Groovy & Gradle: JVM Automation and Build Engineering 课都包含内置代码编辑器，你可以在浏览器中直接编写并运行真实代码，并获得即时 AI 反馈 — 无需本地设置。