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Hello.java
ublic class Hello{ public static void main(String args[]) { System.out.println("hello world\n"); }} Caller.c
#include#include jint create_vm(JavaVM** jvm,JNIEnv** env) { JavaVMInitArgs args; JavaVMOption options[1]; args.version = JNI_VERSION_1_6; args.nOptions = 1; options[0].optionString = "-Djava.class.path=./"; args.options = options; args.ignoreUnrecognized = JNI_FALSE; return JNI_CreateJavaVM(jvm, (void **)env, &args); } int main(int argc,char **argv){ JavaVM* jvm; JNIEnv* env; jclass cls; jmethodID mid; int ret = 0; /*create java virtual machine*/ if(create_vm(&jvm,&env))//return value is not 0 is fail { printf("can not create jvm\n"); return -1; } /*get class*/ cls = (*env)->FindClass(env,"Hello"); if(cls==NULL) { printf("can not find hello class\n"); ret = -1; goto destroy; } /3*create object*/ /*call method *4.1 get method *4.2 create method *4.3 call method */ mid = (*env)->GetStaticMethodID(env,cls,"main","([Ljava/lang/String;)V"); if(mid ==NULL){ ret = -1; printf("can not get the method\n"); goto destroy; } (*env)->CallStaticVoidMethod(env,cls,mid,NULL);destroy: (*jvm)->DestroyJavaVM(jvm); return ret;}
编译java
#javac Hello.java#javap -p -s Hello.class // get Signature
编译C #gcc -I/usr/lib/jvm/java-1.7.0-openjdk-amd64/include/ -o Caller Caller.c -L /usr/lib/jvm/java-7-openjdk-amd64/jre/lib/amd64/server -ljvm 运行程序 #LD_LIBRARY_PATH=/usr/lib/jvm/java-7-openjdk-amd64/jre/lib/amd64/server ./CallerHello2.java
public class Hello2{ public static void main(String args[]) { System.out.println("hello world\n"); } public int Sayhello(String name) { System.out.println("hello,+name"); return 123; }} 2Caller.c
#include#include jint create_vm(JavaVM** jvm,JNIEnv** env) { JavaVMInitArgs args; JavaVMOption options[1]; args.version = JNI_VERSION_1_6; args.nOptions = 1; options[0].optionString = "-Djava.class.path=./"; args.options = options; args.ignoreUnrecognized = JNI_FALSE; return JNI_CreateJavaVM(jvm, (void **)env, &args); } int main(int argc,char **argv){ JavaVM* jvm; JNIEnv* env; jclass cls; jmethodID mid; jmethodID cid; jobject jobj; jstring jstr; int ret = 0; int r; /*create java virtual machine*/ if(create_vm(&jvm,&env))//return value is not 0 is fail { printf("can not create jvm\n"); return -1; } /*get class*/ cls = (*env)->FindClass(env,"Hello2"); if(cls==NULL) { printf("can not find hello class\n"); ret = -1; goto destroy; } /*create object*/ /*3.1 get construct method */ /*3.2 create parameters*/ /*3.3 NewObject*/ /*Get method ID for the String construct*/ cid = (*env)->GetMethodID(env,cls," ","()V"); if(cid==NULL) { ret = -1; printf("can not get construct method\n"); goto destroy; } jobj = (*env)->NewObject(env,cls,cid); if(jobj==NULL) { printf("can not create the object\n"); ret = -1; goto destroy; } /*call method *4.1 get method *4.2 create method *4.3 call method */ mid = (*env)->GetMethodID(env,cls,"Sayhello","(Ljava/lang/String;)I"); if(mid ==NULL){ ret = -1; printf("can not get the method\n"); goto destroy; } jstr = (*env)->NewStringUTF(env,"chnswpuiot"); r = (*env)->CallIntMethod(env,jobj,mid,jstr); printf("r is %d\n",r);destroy: (*jvm)->DestroyJavaVM(jvm); return ret;}
编译java
#javac Hello2.java#javap -p -s Hello2.class // get Signature
编译C #gcc -I/usr/lib/jvm/java-1.7.0-openjdk-amd64/include/ -o 2Caller 2Caller.c -L /usr/lib/jvm/java-7-openjdk-amd64/jre/lib/amd64/server -ljvm 运行程序 #LD_LIBRARY_PATH=/usr/lib/jvm/java-7-openjdk-amd64/jre/lib/amd64/server ./2CallerHello3.java
public class Hello3{ private String name; private int age; public static void main(String args[]) { System.out.println("hello world\n"); } public int Sayhello(String name) { System.out.println("hello,"+name+"! i am is"+this.name+"! my age is"+this.age); return 123; }} 3Caller.c
#include#include jint create_vm(JavaVM** jvm,JNIEnv** env) { JavaVMInitArgs args; JavaVMOption options[1]; args.version = JNI_VERSION_1_6; args.nOptions = 1; options[0].optionString = "-Djava.class.path=./"; args.options = options; args.ignoreUnrecognized = JNI_FALSE; return JNI_CreateJavaVM(jvm, (void **)env, &args); } int main(int argc,char **argv){ JavaVM* jvm; JNIEnv* env; jclass cls; jmethodID mid; jmethodID cid; jobject jobj; jstring jstr; jfieldID nameID; jfieldID ageID; int ret = 0; int r; /*create java virtual machine*/ if(create_vm(&jvm,&env))//return value is not 0 is fail { printf("can not create jvm\n"); return -1; } /*get class*/ cls = (*env)->FindClass(env,"Hello3"); if(cls==NULL) { printf("can not find hello class\n"); ret = -1; goto destroy; } /*create object*/ /*3.1 get construct method */ /*3.2 create parameters*/ /*3.3 NewObject*/ /*Get method ID for the String construct*/ cid = (*env)->GetMethodID(env,cls," ","()V"); if(cid==NULL) { ret = -1; printf("can not get construct method\n"); goto destroy; } jobj = (*env)->NewObject(env,cls,cid); if(jobj==NULL) { printf("can not create the object\n"); ret = -1; goto destroy; } /* *get/set filed *1.get filed id *2.get/set filed */ nameID = (*env)->GetFieldID(env,cls,"name","Ljava/lang/String;"); if(nameID==NULL) { ret = -1; printf("can not get the field name\n"); goto destroy; } jstr = (*env)->NewStringUTF(env,"chenswpu"); (*env)->SetObjectField(env,jobj,nameID,jstr); ageID = (*env)->GetFieldID(env,cls,"age","I"); if(ageID==NULL) { ret = -1; printf("cna not get field age"); goto destroy; } (*env)->SetIntField(env,jobj,ageID,10); /*call method *4.1 get method *4.2 create method *4.3 call method */ mid = (*env)->GetMethodID(env,cls,"Sayhello","(Ljava/lang/String;)I"); if(mid ==NULL){ ret = -1; printf("can not get the method\n"); goto destroy; } jstr = (*env)->NewStringUTF(env,"chnswpuiot"); r = (*env)->CallIntMethod(env,jobj,mid,jstr); printf("r is %d\n",r);destroy: (*jvm)->DestroyJavaVM(jvm); return ret;}
编译java
#javac Hello3.java #javap -p -s Hello3.class // get Signature 编译C #gcc -I/usr/lib/jvm/java-1.7.0-openjdk-amd64/include/ -o 3Caller 3Caller.c -L /usr/lib/jvm/java-7-openjdk-amd64/jre/lib/amd64/server -ljvm 运行程序 #LD_LIBRARY_PATH=/usr/lib/jvm/java-7-openjdk-amd64/jre/lib/amd64/server ./3Caller转载地址：http://mtomb.baihongyu.com/