不满意的链接错误:java.library.path中没有库文件 [英] Unsatisfied link error: no library file in java.library.path
问题描述
我有这样的目录结构
.
--compile_c.sh
--compile_java.sh
--config.sh
--execute_java.sh
--run.sh
--src
--ccode
--jnitest_SimpleJNITest.h
--rtm_simple.c
--jnitest
--SimpleJNITest.java
--lib
--rtm_simple.so
--classes
--SimpleJNITest.class
当SimpleJNITest
具有在rtm_simple.c
中充实的native
方法时,如何正确运行SimpleJNITest
?
How do I correctly run SimpleJNITest
when it has a native
method that is fleshed out in rtm_simple.c
?
目前,我已经定义
config.sh
targetDir="classes"
libDir="lib"
srcDir="src"
MainPackage="jnitest"
Main="SimpleJNITest"
ccodeDir="ccode"
cFileName="rtm_simple"
jdkDir="/home/user/local/java/jdk1.7.0_65"
mkdir -p "$targetDir"
mkdir -p "$libDir"
并且正在尝试运行
run.sh
#!/bin/bash
source compile_java.sh
javah -d "${srcDir}/${ccodeDir}" -cp "$targetDir" -jni "${MainPackage}.${Main}"
source compile_c.sh
source execute_java.sh
其中
compile_java.sh
#!/bin/bash
source config.sh
javac -d "$targetDir" -sourcepath "$srcDir" -cp "${targetDir}:${libDir}/*" "${srcDir}/${MainPackage}/${Main}.java"
compile_c.sh
#!/bin/bash
source config.sh
cFile="${srcDir}/${ccodeDir}/${cFileName}.c"
soFile="${libDir}/${cFileName}.so"
gcc -g -shared -fpic -I "${jdkDir}/include" -I "${jdkDir}/include/linux" $cFile -o $soFile
execute_java.sh
#!/bin/bash
source config.sh
export LD_LIBRARY_PATH="$LD_LIBRARY_PATH:${libDir}"
java -cp "${targetDir}:${libDir}/*" "${MainPackage}.${Main}"
(也尝试过java -Djava.library.path="$LD_LIBRARY_PATH:$libDir" -cp "${targetDir}:${libDir}/*" "${MainPackage}.${Main}"
)
输出
$ ./run.sh
Exception in thread "main" java.lang.UnsatisfiedLinkError: no rtm_simple in java.library.path
at java.lang.ClassLoader.loadLibrary(ClassLoader.java:1867)
at java.lang.Runtime.loadLibrary0(Runtime.java:870)
at java.lang.System.loadLibrary(System.java:1122)
at jnitest.SimpleJNITest.main(SimpleJNITest.java:17)
代码:
SimpleJNITest.java
package jnitest;
public class SimpleJNITest{
public static final int NOF_ITERATIONS = 100000;
public native int nofAborts(int nofTransactions);
public void test(){
int nofAborts = nofAborts(NOF_ITERATIONS);
System.out.println(String.format("successfully completed %d transactions and had to retry %d times",nofAborts));
}
public static void main(String[] args) {
System.loadLibrary("rtm_simple");
new SimpleJNITest().test();
}
}
(也尝试使用System.loadLibary("rtm_simple.so");
)
jnitest_SimpleJNITest.h
/* DO NOT EDIT THIS FILE - it is machine generated */
#include <jni.h>
/* Header for class jnitest_SimpleJNITest */
#ifndef _Included_jnitest_SimpleJNITest
#define _Included_jnitest_SimpleJNITest
#ifdef __cplusplus
extern "C" {
#endif
#undef jnitest_SimpleJNITest_NOF_ITERATIONS
#define jnitest_SimpleJNITest_NOF_ITERATIONS 100000L
/*
* Class: jnitest_SimpleJNITest
* Method: nofAborts
* Signature: (I)I
*/
JNIEXPORT jint JNICALL Java_jnitest_SimpleJNITest_nofAborts
(JNIEnv *, jobject, jint);
#ifdef __cplusplus
}
#endif
#endif
rtm_simple.c
#include <jni.h>
#include "jnitest_SimpleJNITest.h"
JNIEXPORT jint JNICALL
Java_jnitest_SimpleJNITest_nofAborts(JNIEnv* env, jobject obj, jint nof_iterations){
volatile int abort_counter = 0;
volatile int i = 0;
while (i < nof_iterations) {
__asm__ __volatile__ (
"xbegin 1f" /*1f: local label 1, look forward to find first*/
:"+rm"(i) /*artificial dependency to prevent re-ordering*/
);
++i;
__asm__ __volatile__ (
"xend\n\t"
"jmp 2f\n" /*not aborted ==> jump to local label 2*/
"1:\n\t" /*local label 1 (jumped to when transaction is aborted)*/
:"+rm"(abort_counter) /*artificial dependency*/
:"rm"(i) /*artificial dependency*/
);
++abort_counter;
__asm__ __volatile__ (
"2:" /*local label 2 (jumped to when transactoin is NOt aborted)*/
:"+rm"(abort_counter) /*artificial dependency*/
:"rm"(i) /*artificial dependency*/
);
}
if(i != nof_iterations) return -1;
return abort_counter;
}
推荐答案
如果要指定文件名,则需要使用 System.loadLibrary(String)
方法. loadLibrary
以平台相关的方式转换指定的名称.在您的系统上,可能添加了lib
前缀和.so
后缀,但这意味着无论您如何调用loadLibrary
,即使位于rtm_simple.so
上的文件也无法加载.库搜索路径.或者换句话说,如果您确实想使用loadLibrary
,则需要将文件重命名为librtm_simple.so
.
If you want to specify a file name, you need to use System.load(String)
, and not the System.loadLibrary(String)
method. loadLibrary
transforms the specified name in a platform-dependent manner. On your system, a lib
prefix and .so
suffix is probably added, but this means no matter how you call loadLibrary
, it won't be able to load a file called rtm_simple.so
even if it is located on the library search path. Or put differently, if you do want to use loadLibrary
, you need to rename the file to librtm_simple.so
.
如果在strace -fF
下运行JVM,则可以看到JVM使用的路径.
You can see the paths the JVM uses if you run it under strace -fF
.
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