可执行找到32位Java时，它应该找到64位

Question

我写的一个PowerShell脚本，需要投入的Java3D的正确版本到客户端计算机的可执行文件。通过适当的版本，我的意思是当用户打开CMD并键入'java -version'时，它会提供32位或64位。我需要为正确的架构选择dll文件。

的问题是，我发现安装了32位和64位JDK 64位W7系统的测试用例。只有64位版本包含在PATH环境变量中。但是，当我运行我的批处理脚本或可执行文件并回显java -version时，会出现32位Java。因此，它安装了32位dll，当用户转到cmd时，它使用64位，因此它不兼容。

由于32位JDK没有在PATH变量包括，为什么脚本运行32位的Java和它从哪儿得到这个链接？

Answer 1

谷歌Chrome和Firefox仍在64位Windows操作系统的32位应用程序，那么你很可能执行SysWOW64中下由他们安装了32位Java - 特别是如果您正在安装使用的是运行Java Web Start的应用程序在这些浏览器之一内。

我有完全相同的问题，我已经实现了安装的Java类的系统范围内的搜索，这样我就可以创建一个调用使用适当的位数确切的java.exe的批处理文件。

这是你所需要的：

/** 
* Java Finder by [email protected](828681) is licensed under a Creative Commons Attribution 3.0 Unported License. 
* Needs WinRegistry.java. Get it at: https://stackoverflow.com/questions/62289/read-write-to-windows-registry-using-java 
* 
* JavaFinder - Windows-specific classes to search for all installed versions of java on this system 
* Author: [email protected] (828681) 
*****************************************************************************/ 

import java.util.*; 
import java.io.*; 

/** 
* Helper class to fetch the stdout and stderr outputs from started Runtime execs 
* Modified from http://www.javaworld.com/javaworld/jw-12-2000/jw-1229-traps.html?page=4 
*****************************************************************************/ 
class RuntimeStreamer extends Thread { 
    InputStream is; 
    String lines; 

    RuntimeStreamer(InputStream is) { 
     this.is = is; 
     this.lines = ""; 
    } 
    public String contents() { 
     return this.lines; 
    } 

    public void run() { 
     try { 
      InputStreamReader isr = new InputStreamReader(is); 
      BufferedReader br = new BufferedReader(isr); 
      String line = null; 
      while ((line = br.readLine()) != null) { 
       this.lines += line + "\n"; 
      } 
     } catch (IOException ioe) { 
      ioe.printStackTrace(); 
     } 
    } 

    /** 
    * Execute a command and wait for it to finish 
    * @return The resulting stdout and stderr outputs concatenated 
    ****************************************************************************/ 
    public static String execute(String[] cmdArray) { 
     try { 
      Runtime runtime = Runtime.getRuntime(); 
      Process proc = runtime.exec(cmdArray); 
      RuntimeStreamer outputStreamer = new RuntimeStreamer(proc.getInputStream()); 
      RuntimeStreamer errorStreamer = new RuntimeStreamer(proc.getErrorStream()); 
      outputStreamer.start(); 
      errorStreamer.start(); 
      proc.waitFor(); 
      return outputStreamer.contents() + errorStreamer.contents(); 
     } catch (Throwable t) { 
      t.printStackTrace(); 
     } 
     return null; 
    } 
    public static String execute(String cmd) { 
     String[] cmdArray = { cmd }; 
     return RuntimeStreamer.execute(cmdArray); 
    } 
} 

/** 
* Helper struct to hold information about one installed java version 
****************************************************************************/ 
class JavaInfo { 
    public String path;  //! Full path to java.exe executable file 
    public String version;  //! Version string. "Unkown" if the java process returned non-standard version string 
    public boolean is64bits; //! true for 64-bit javas, false for 32 

    /** 
    * Calls 'javaPath -version' and parses the results 
    * @param javaPath: path to a java.exe executable 
    ****************************************************************************/ 
    public JavaInfo(String javaPath) { 
     String versionInfo = RuntimeStreamer.execute(new String[] { javaPath, "-version" }); 
     String[] tokens = versionInfo.split("\""); 

     if (tokens.length < 2) this.version = "Unkown"; 
     else this.version = tokens[1]; 
     this.is64bits = versionInfo.toUpperCase().contains("64-BIT"); 
     this.path  = javaPath; 
    } 

    /** 
    * @return Human-readable contents of this JavaInfo instance 
    ****************************************************************************/ 
    public String toString() { 
     return this.path + ":\n Version: " + this.version + "\n Bitness: " + (this.is64bits ? "64-bits" : "32-bits"); 
    } 
} 

/** 
* Windows-specific java versions finder 
*****************************************************************************/ 
public class JavaFinder { 

    /** 
    * @return: A list of javaExec paths found under this registry key (rooted at HKEY_LOCAL_MACHINE) 
    * @param wow64 0 for standard registry access (32-bits for 32-bit app, 64-bits for 64-bits app) 
    *    or WinRegistry.KEY_WOW64_32KEY to force access to 32-bit registry view, 
    *    or WinRegistry.KEY_WOW64_64KEY to force access to 64-bit registry view 
    * @param previous: Insert all entries from this list at the beggining of the results 
    *************************************************************************/ 
    private static List<String> searchRegistry(String key, int wow64, List<String> previous) { 
     List<String> result = previous; 
     try { 
      List<String> entries = WinRegistry.readStringSubKeys(WinRegistry.HKEY_LOCAL_MACHINE, key, wow64); 
      for (int i = 0; entries != null && i < entries.size(); i++) { 
       String val = WinRegistry.readString(WinRegistry.HKEY_LOCAL_MACHINE, key + "\\" + entries.get(i), "JavaHome", wow64); 
       if (!result.contains(val + "\\bin\\java.exe")) { 
        result.add(val + "\\bin\\java.exe"); 
       } 
      } 
     } catch (Throwable t) { 
      t.printStackTrace(); 
     } 
     return result; 
    } 

    /** 
    * @return: A list of JavaInfo with informations about all javas installed on this machine 
    * Searches and returns results in this order: 
    * HKEY_LOCAL_MACHINE\SOFTWARE\JavaSoft\Java Runtime Environment (32-bits view) 
    * HKEY_LOCAL_MACHINE\SOFTWARE\JavaSoft\Java Runtime Environment (64-bits view) 
    * HKEY_LOCAL_MACHINE\SOFTWARE\JavaSoft\Java Development Kit  (32-bits view) 
    * HKEY_LOCAL_MACHINE\SOFTWARE\JavaSoft\Java Development Kit  (64-bits view) 
    * WINDIR\system32 
    * WINDIR\SysWOW64 
    ****************************************************************************/ 
    public static List<JavaInfo> findJavas() { 
     List<String> javaExecs = new ArrayList<String>(); 

     javaExecs = JavaFinder.searchRegistry("SOFTWARE\\JavaSoft\\Java Runtime Environment", WinRegistry.KEY_WOW64_32KEY, javaExecs); 
     javaExecs = JavaFinder.searchRegistry("SOFTWARE\\JavaSoft\\Java Runtime Environment", WinRegistry.KEY_WOW64_64KEY, javaExecs); 
     javaExecs = JavaFinder.searchRegistry("SOFTWARE\\JavaSoft\\Java Development Kit",  WinRegistry.KEY_WOW64_32KEY, javaExecs); 
     javaExecs = JavaFinder.searchRegistry("SOFTWARE\\JavaSoft\\Java Development Kit",  WinRegistry.KEY_WOW64_64KEY, javaExecs); 

     javaExecs.add(System.getenv("WINDIR") + "\\system32\\java.exe"); 
     javaExecs.add(System.getenv("WINDIR") + "\\SysWOW64\\java.exe"); 

     List<JavaInfo> result = new ArrayList<JavaInfo>(); 
     for (String javaPath: javaExecs) { 
      if (!(new File(javaPath).exists())) continue; 
      result.add(new JavaInfo(javaPath)); 
     } 
     return result; 
    } 

    /** 
    * @return: The path to a java.exe that has the same bitness as the OS 
    * (or null if no matching java is found) 
    ****************************************************************************/ 
    public static String getOSBitnessJava() { 
     String arch  = System.getenv("PROCESSOR_ARCHITECTURE"); 
     String wow64Arch = System.getenv("PROCESSOR_ARCHITEW6432"); 
     boolean isOS64 = arch.endsWith("64") || (wow64Arch != null && wow64Arch.endsWith("64")); 

     List<JavaInfo> javas = JavaFinder.findJavas(); 
     for (int i = 0; i < javas.size(); i++) { 
      if (javas.get(i).is64bits == isOS64) return javas.get(i).path; 
     } 
     return null; 
    } 

    /** 
    * Standalone testing - lists all Javas in the system 
    ****************************************************************************/ 
    public static void main(String [] args) { 
     List<JavaInfo> javas = JavaFinder.findJavas(); 
     for (int i = 0; i < javas.size(); i++) { 
      System.out.println("\n" + javas.get(i)); 
     } 
    } 
} 

您还需要更新WinRegistry.java读值从两个从32位和Windows注册表的64位部分：https://stackoverflow.com/a/11854901/828681

我通常不是java程序员，所以我的代码可能不遵循java约定。告我。

这里是JavaFinder.findJavas（）我的Win 7的64位机器上的结果：

>java JavaFinder 

C:\Program Files (x86)\Java\jre6\bin\java.exe: 
    Version: 1.6.0_31 
    Bitness: 32-bits 

C:\Program Files\Java\jre6\bin\java.exe: 
    Version: 1.6.0_31 
    Bitness: 64-bits 

D:\Dev\Java\jdk1.6.0_31\bin\java.exe: 
    Version: 1.6.0_31 
    Bitness: 64-bits 

C:\Windows\system32\java.exe: 
    Version: 1.6.0_31 
    Bitness: 64-bits 

C:\Windows\SysWOW64\java.exe: 
    Version: 1.6.0_31 
    Bitness: 32-bits 

注有SysWOW64中下一个32位的java.exe - 它会通过网络得到所谓因为它们是32位应用程序，所以它们在Chrome或Firefox中运行时除外 - 除非使用JavaFinder查找正确使用的java.exe并使用它的完整路径。