一、Java类中声明本地方法，使用native关键字
public class MyNative {
public void showParms(String s, int i, boolean b) {
showParms0(s, i, b);
}
public int hypotenuse(int a, int b) {
return hypotenuse0(a, b);
}
public void setArray(boolean[] ba) {
for (int i = 0; i < ba.length; i++)
ba[i] = true;
setArray0(ba);
}
public void showStrings(String[] sa) {
showStrings0(sa);
}
public String[] getStrings() {
return getStrings0();
}
private native void showParms0(String s, int i, boolean b);
private native int hypotenuse0(int a, int b);
private native void setArray0(boolean[] ba);
private native void showStrings0(String[] sa);
private native String[] getStrings0();
static {
System.loadLibrary("MyNative");
}
public static void main(String[] args) {
MyNative obj = new MyNative();
obj.showParms("Hello", 23, true);
obj.showParms("World", 34, false);
System.out.println(obj.hypotenuse(3, 4));
System.out.println(obj.hypotenuse(9, 12));
boolean[] ba = new boolean[5];
obj.setArray(ba);
for (int i = 0; i < ba.length; i++)
System.out.println(ba[i]);
String[] sa = new String[] { "Hello,", "world!", "JNI", "is", "fun." };
obj.showStrings(sa);
obj.showStrings(obj.getStrings());
}
}
loadLibrary
public static void loadLibrary
(String
libname)Loads the system library specified by the libname argument. The manner in which a library name is mapped to the actual system library is system dependent.
The call System.loadLibrary(name) is effectively equivalent to the call
Runtime.getRuntime().loadLibrary(name) Parameters:
libname - the name of the library.
Throws:
SecurityException - if a security manager exists and its checkLink method doesn't allow loading of the specified dynamic library
UnsatisfiedLinkError - if the library does not exist.
NullPointerException - if libname is null
See Also:
Runtime.loadLibrary(java.lang.String) , SecurityManager.checkLink(java.lang.String)
二、生成.class文件，并使用javah命令，将.class文件生成.h文件
javac MyNative.class
javah -jni MyNative
javac MyNative.class
javah -jni MyNative
生成的.h文件如下
/* DO NOT EDIT THIS FILE - it is machine generated */
#include <jni.h>
/* Header for class MyNative */
#ifndef _Included_MyNative
#define _Included_MyNative
#ifdef __cplusplus
extern "C" {
#endif
/*
* Class: MyNative
* Method: getStrings0
* Signature: ()[Ljava/lang/String;
*/
JNIEXPORT jobjectArray JNICALL Java_MyNative_getStrings0
(JNIEnv *, jobject);
/*
* Class: MyNative
* Method: showStrings0
* Signature: ([Ljava/lang/String;)V
*/
JNIEXPORT void JNICALL Java_MyNative_showStrings0
(JNIEnv *, jobject, jobjectArray);
/*
* Class: MyNative
* Method: showParms0
* Signature: (Ljava/lang/String;IZ)V
*/
JNIEXPORT void JNICALL Java_MyNative_showParms0
(JNIEnv *, jobject, jstring, jint, jboolean);
/*
* Class: MyNative
* Method: hypotenuse0
* Signature: (II)I
*/
JNIEXPORT jint JNICALL Java_MyNative_hypotenuse0
(JNIEnv *, jobject, jint, jint);
/*
* Class: MyNative
* Method: setArray0
* Signature: ([Z)V
*/
JNIEXPORT void JNICALL Java_MyNative_setArray0
(JNIEnv *, jobject, jbooleanArray);
#ifdef __cplusplus
}
#endif
#endif