我正在从PowerShell脚本编写一个可执行文件，需要将正确版本的Java3D放到客户端计算机上。通过适当的版本，我的意思是当用户打开CMD并输入'java -version'时，它会给出32位或64位。我需要为正确的架构选择dll文件。
问题是，我发现了一个安装了32位和64位JDK的64位W7系统的测试用例。 PATH环境变量中仅包含64位版本。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32位dll，当用户转到cmd时，它使用64位，因此它不兼容。
由于PATH变量中不包含32位JDK，为什么脚本运行32位java以及它在哪里获得此链接？
答案 0 :(得分：1)
Google Chrome和Firefox仍然是64位Windows操作系统下的32位应用程序，因此您可能正在执行SysWOW64下安装的32位Java - 特别是如果您使用内部运行的Java Web Start安装应用程序其中一个浏览器。
我遇到了完全相同的问题，我已经对已安装的javas实施了系统范围的搜索，这样我就可以创建一个批处理文件来调用具有适当位数的精确java.exe。
这就是你需要的：
/**
* Java Finder by petrucio@stackoverflow(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: petrucio@stackoverflow (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));
}
}
}
您还需要更新的WinRegistry.java来读取Windows注册表的32位和64位部分的值：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。告诉我。
以下是我的Win 7 64位计算机上的JavaFinder.findJavas（）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
请注意，在SysWOW64下有一个32位的java.exe - 由于它们是32位应用程序，因此在Chrome或Firefox中运行时，它将被Web启动程序调用 - 除非您使用JavaFinder查找正确位置的java。 exe并使用它的完整路径。