Unity安卓构建环境配置：JDK8无法下载及路径配置故障求助

Hey there, let's work through this JDK problem you're facing step by step—you're closer than you think!

1. Clear Up the JRE vs JDK Mix-Up #

First, let's untangle the confusion:

• When you ran javac -version and got javac 1.8.0_XX, that means a JDK is installed on your system. The javac tool only comes with JDK—JRE doesn't include compilation tools, so this output confirms you have the full JDK somewhere.
• Your mistake was pointing Unity to the JRE path (C:\Program Files\Java\jre1.8.0). Unity needs the actual JDK root directory, not just the JRE, because Android builds rely on JDK-specific tools like javac.

2. Locate Your Real JDK Installation Path #

The C:\ProgramData\Oracle\Java\javapath you found is just a shortcut directory that redirects to Java executables—it's not the real JDK home folder. To find the actual path:

• Open Command Prompt again (Win+R > cmd)
• Run this command:

  for %i in (javac.exe) do @echo. %~$PATH:i
  

• This will give you the full path to javac.exe, something like C:\Program Files\Java\jdk1.8.0_291\bin\javac.exe
• Strip off the \bin\javac.exe part, and you'll have your JDK root directory—for example, C:\Program Files\Java\jdk1.8.0_291

3. Configure Unity with the Correct JDK Path #

• Open Unity, go to Edit > Preferences > External Tools (or Edit > Project Settings > Player > Android > External Tools, depending on your Unity version)
• Click the browse button for JDK, and select the root directory you just found (e.g., C:\Program Files\Java\jdk1.8.0_291)
• Unity should now recognize this as a valid JDK installation.

4. If You Still Need to Download JDK (Or Can't Locate the Existing One) #

If the above steps don't turn up a proper JDK, or you need to reinstall:

• Try switching to a different network (like a mobile hotspot)—corporate firewalls or ISP restrictions often block Oracle's download servers.
• Consider using an OpenJDK distribution instead (it's free and reliable). Look for OpenJDK 8 (since Unity's older Android build tools work best with JDK 8) from trusted providers.
• Double-check your firewall and proxy settings to ensure they aren't blocking the download.

Quick Recap #

• The presence of javac confirms JDK is installed—you just need to find its root folder, not JRE or shortcut paths.
• Unity requires the JDK root directory (not bin or javapath) to validate the installation.

内容的提问来源于stack exchange，提问作者RealAnyOne