JNI_learn/c/reference/JNI_globalReference.c

#include <stdint.h>
#include "space_anyi_jni_reference_GlobalReferenceTest.h"
JNIEXPORT jlong JNICALL Java_space_anyi_jni_reference_GlobalReferenceTest_getPersonHandler(JNIEnv *env, jobject this){
    //1.获取对应的jclass
    jclass class_Person = (*env)->FindClass(env, "Lspace/anyi/jni/reference/Person;");
    //2.获取对应的构造方法
    jmethodID constructor = (*env)->GetMethodID(env, class_Person, "<init>", "(Ljava/lang/String;I)V");
    //3.创建对象
    jstring name = (*env)->NewStringUTF(env, "杨逸");
    jobject person = (*env)->NewObject(env, class_Person, constructor,name,18);
    //4.获取全局引用
    jobject globalReference = (*env)->NewGlobalRef(env, person);
    //5.转换为句柄,使用intptr_t类型作为中间类型,避免精度丢失
    jlong handler = (jlong)(intptr_t)globalReference;
    return handler;
}

JNIEXPORT jobject JNICALL Java_space_anyi_jni_reference_GlobalReferenceTest_getPerson(JNIEnv *env, jobject this, jlong handler){
    //1.通过句柄获取全局引用,使用intptr_t类型作为中间类型
    jobject person = (jobject)(intptr_t)handler;
    //2.返回对象
    return person;
}

JNIEXPORT void JNICALL Java_space_anyi_jni_reference_GlobalReferenceTest_freePerson(JNIEnv *env, jobject this, jlong handler){
    //1.通过句柄释放全局引用的内存
    (*env)->DeleteGlobalRef(env, (jobject)(intptr_t)handler);
}