Java JNI由浅入深(包括：Java和C++互传ArrayList泛型对象参数)

JavaJNI由浅入深(包括：Java和C++互传ArrayList泛型对象参数)

2010-11-2509:571168人阅读评论(1)收藏举报

我们知道Java是一个运行在虚拟机里面的高级的编程语言，如果要调用系统的动态链接库的话，就要先声明native修饰的方法(类似接口里面的方法)，再由C/C++程序来实现(类似实现接口里的方法)。这样Java调用这些native方法就相当于调用了C/C++里面实现了的方法。通常我们把这种机制叫做JNI(JavaNativeInterfac)，即Java本地编程接口

Android也同理，要学会在Android上进行NDK开发，首先我们到打好javaJNI的基础。现在我们暂时把Android开发丢到一边先，试试在Java之下编译一个C动态链接库，再用Java程序调用。

1)先来个最简单的打印HelloWorld例子：

Java代码(HelloJni.java)：

viewplainprint?

1.importjava.util.*;

2.publicclassHelloJni{

3.

4.static{

5.System.loadLibrary("hello");

6.}

7.publicnativestaticvoidsayHello();

8.publicstaticvoidmain(String[]args)

9.{

10.HelloJni.sayHello();

11.}

12.}

importjava.util.*;publicclassHelloJni{static{System.loadLibrary("hello");}publicnativestaticvoidsayHello();publicstaticvoidmain(String[]args){HelloJni.sayHello();}}

生成头文件(HelloJni.h)：

先javacHelloJni.java编译你的Java源码，再javah–jniHelloJni生成所需的头文件

头文件内容是这样的：

viewplainprint?

1./*DONOTEDITTHISFILE-itismachinegenerated*/

2.#include<jni.h>

3./*HeaderforclassHelloJni*/

4.#ifndef_Included_HelloJni

5.#define_Included_HelloJni

6.#ifdef__cplusplus

7.extern"C"{

8.#endif

9.JNIEXPORTvoidJNICALLJava_HelloJni_sayHello(JNIEnv*,jclass);

10.#ifdef__cplusplus

11.}

12.#endif

13.#endif

/*DONOTEDITTHISFILE-itismachinegenerated*/#include<jni.h>/*HeaderforclassHelloJni*/#ifndef_Included_HelloJni#define_Included_HelloJni#ifdef__cplusplusextern"C"{#endifJNIEXPORTvoidJNICALLJava_HelloJni_sayHello(JNIEnv*,jclass);#ifdef__cplusplus}#endif#endif

实现头文件声明的方法(HelloJni.cpp)

viewplainprint?

1.#include"HelloJni.h"

2.JNIEXPORTvoidJNICALLJava_HelloJni_sayHello(JNIEnv*env,jclasscls)

3.{

4.printf("HelloWorld");

5.}

#include"HelloJni.h"JNIEXPORTvoidJNICALLJava_HelloJni_sayHello(JNIEnv*env,jclasscls){printf("HelloWorld");}

编译命令:g++-I$JAVA_HOME/include-I$JAVA_HOME/include/linuxHelloJni.cpp-shared-olibhello.so

命令参数解析：-I是指引入java虚拟机的库的路径，-shared是指编译成动态链接库(共享库)–o输出文件名(注意，在Linux平台下的动态链接库有一个命名格式：“lib+库名+.so”在java代码里面loadLibrary的时候不要加lib前缀和.so后缀)

由于我这里把这个动态链接库编译放在当前目录下，所以还要设置环境变量LD_LIBRARY_PATH=该so动态链接库所在的目录，才能正常运行

#############################+++华丽的分割线+++###########################

2)好了，可以打印HelloWorld出来后，我们再深入一点点，传入一个int的数，在C/C++代码里面加1后返回。

Java代码(HelloJni.java)：

viewplainprint?

1.publicclassHelloJni{

2.static{

3.System.loadLibrary("hello");

4.}

5.publicstaticnativevoidsayHello();

6.publicnativeintgetInt();

7.publicnativevoidsetInt(inti);

8.publicstaticvoidmain(Stringargs[]){

9.//HelloJni.sayHello();

10.HelloJnihello=newHelloJni();

11.hello.setInt(2);

12.System.out.println(hello.getInt());

13.}

14.}

publicclassHelloJni{static{System.loadLibrary("hello");}publicstaticnativevoidsayHello();publicnativeintgetInt();publicnativevoidsetInt(inti);publicstaticvoidmain(Stringargs[]){//HelloJni.sayHello();HelloJnihello=newHelloJni();hello.setInt(2);System.out.println(hello.getInt());}}

生成头文件(HelloJni.h)：

viewplainprint?

1./*DONOTEDITTHISFILE-itismachinegenerated*/

2.#include<jni.h>

3./*HeaderforclassHelloJni*/

4.#ifndef_Included_HelloJni

5.#define_Included_HelloJni

6.#ifdef__cplusplus

7.extern"C"{

8.#endif

9.JNIEXPORTvoidJNICALLJava_HelloJni_sayHello(JNIEnv*,jclass);

10.JNIEXPORTjintJNICALLJava_HelloJni_getInt(JNIEnv*,jobject);

11.JNIEXPORTvoidJNICALLJava_HelloJni_setInt(JNIEnv*,jobject,jint);

12.#ifdef__cplusplus

13.}

14.#endif

15.#endif

/*DONOTEDITTHISFILE-itismachinegenerated*/#include<jni.h>/*HeaderforclassHelloJni*/#ifndef_Included_HelloJni#define_Included_HelloJni#ifdef__cplusplusextern"C"{#endifJNIEXPORTvoidJNICALLJava_HelloJni_sayHello(JNIEnv*,jclass);JNIEXPORTjintJNICALLJava_HelloJni_getInt(JNIEnv*,jobject);JNIEXPORTvoidJNICALLJava_HelloJni_setInt(JNIEnv*,jobject,jint);#ifdef__cplusplus}#endif#endif

实现头文件声明的方法(HelloJni.cpp)

viewplainprint?

1.#include"HelloJni.h"

2.inti=1;

3.JNIEXPORTvoidJNICALLJava_HelloJni_sayHello

4.(JNIEnv*env,jclasscls){

5.printf("HelloWorld/n");

6.}

7.JNIEXPORTjintJNICALLJava_HelloJni_getInt

8.(JNIEnv*env,jobjectthiz){

9.returni;

10.}

11.JNIEXPORTvoidJNICALLJava_HelloJni_setInt

12.(JNIEnv*env,jobjectthiz,jintji){

13.i=ji+1;

14.}

#include"HelloJni.h"inti=1;JNIEXPORTvoidJNICALLJava_HelloJni_sayHello(JNIEnv*env,jclasscls){printf("HelloWorld/n");}JNIEXPORTjintJNICALLJava_HelloJni_getInt(JNIEnv*env,jobjectthiz){returni;}JNIEXPORTvoidJNICALLJava_HelloJni_setInt(JNIEnv*env,jobjectthiz,jintji){i=ji+1;}

运行结果：打印2

3)只是传入简单的数据类型不爽，这次让C/C++生成个Java对象返回

Java代码：pojo实体类(User.java)

viewplainprint?

1.publicclassUser{

2.privatelongid;

3.privateStringuserName;

4.privatebooleanisMan;

5.privateintage;

6.publicUser(){}

7.publicUser(longid,StringuserName,booleanisMan,intage){

8.super();

9.this.id=id;

10.this.userName=userName;

11.this.isMan=isMan;

12.this.age=age;

13.}

14.publiclonggetId(){

15.returnid;

16.}

17.publicvoidsetId(longid){

18.this.id=id;

19.}

20.publicStringgetUserName(){

21.returnuserName;

22.}

23.publicvoidsetUserName(StringuserName){

24.this.userName=userName;

25.}

26.publicbooleanisMan(){

27.returnisMan;

28.}

29.publicvoidsetMan(booleanisMan){

30.this.isMan=isMan;

31.}

32.publicintgetAge(){

33.returnage;

34.}

35.publicvoidsetAge(intage){

36.this.age=age;

37.}

38.}

publicclassUser{privatelongid;privateStringuserName;privatebooleanisMan;privateintage;publicUser(){}publicUser(longid,StringuserName,booleanisMan,intage){super();this.id=id;this.userName=userName;this.isMan=isMan;this.age=age;}publiclonggetId(){returnid;}publicvoidsetId(longid){this.id=id;}publicStringgetUserName(){returnuserName;}publicvoidsetUserName(StringuserName){this.userName=userName;}publicbooleanisMan(){returnisMan;}publicvoidsetMan(booleanisMan){this.isMan=isMan;}publicintgetAge(){returnage;}publicvoidsetAge(intage){this.age=age;}}

Java代码(HelloJni.java)：

viewplainprint?

1.publicclassHelloJni{

2.static{

3.System.loadLibrary("userbean");

4.}

5.publicstaticnativevoidsayHello();

6.publicnativeintgetInt();

7.publicnativevoidsetInt(inti);

8.publicnativevoidsetUser(StringuserName);

9.publicnativeUsergetUser();

10.publicstaticvoidmain(Stringargs[]){

11.//HelloJni.sayHello();

12.HelloJnihello=newHelloJni();

13.//hello.setInt(2);

14.//System.out.println(hello.getInt());

15.hello.setUser("LiangYaotian");

16.Useruser=hello.getUser();

17.System.out.println("userfromc/c++");

18.System.out.println("name:"+user.getUserName());

19.System.out.println("isMan?:"+user.isMan());

20.System.out.println("age:"+user.getAge());

21.}

22.}

publicclassHelloJni{static{System.loadLibrary("userbean");}publicstaticnativevoidsayHello();publicnativeintgetInt();publicnativevoidsetInt(inti);publicnativevoidsetUser(StringuserName);publicnativeUsergetUser();publicstaticvoidmain(Stringargs[]){//HelloJni.sayHello();HelloJnihello=newHelloJni();//hello.setInt(2);//System.out.println(hello.getInt());hello.setUser("LiangYaotian");Useruser=hello.getUser();System.out.println("userfromc/c++");System.out.println("name:"+user.getUserName());System.out.println("isMan?:"+user.isMan());System.out.println("age:"+user.getAge());}}

生成头文件(HelloJni.h)：

viewplainprint?

1.#include<jni.h>

2./*HeaderforclassHelloJni*/

3.#ifndef_Included_HelloJni

4.#define_Included_HelloJni

5.#ifdef__cplusplus

6.extern"C"{

7.#endif

8.JNIEXPORTvoidJNICALLJava_HelloJni_sayHello(JNIEnv*,jclass);

9.JNIEXPORTjintJNICALLJava_HelloJni_getInt(JNIEnv*,jobject);

10.JNIEXPORTvoidJNICALLJava_HelloJni_setInt(JNIEnv*,jobject,jint);

11.JNIEXPORTvoidJNICALLJava_HelloJni_setUser(JNIEnv*,jobject,jstring);

12.JNIEXPORTjobjectJNICALLJava_HelloJni_getUser(JNIEnv*,jobject);

13.#ifdef__cplusplus

14.}

15.#endif

16.#endif

#include<jni.h>/*HeaderforclassHelloJni*/#ifndef_Included_HelloJni#define_Included_HelloJni#ifdef__cplusplusextern"C"{#endifJNIEXPORTvoidJNICALLJava_HelloJni_sayHello(JNIEnv*,jclass);JNIEXPORTjintJNICALLJava_HelloJni_getInt(JNIEnv*,jobject);JNIEXPORTvoidJNICALLJava_HelloJni_setInt(JNIEnv*,jobject,jint);JNIEXPORTvoidJNICALLJava_HelloJni_setUser(JNIEnv*,jobject,jstring);JNIEXPORTjobjectJNICALLJava_HelloJni_getUser(JNIEnv*,jobject);#ifdef__cplusplus}#endif#endif

实现头文件声明的方法(HelloJni.cpp)

viewplainprint?

1.#include<iostream>

2.#include<stdio.h>

3.usingnamespacestd;

4.inti=1;

5.jobjectuser;

6.JNIEXPORTvoidJNICALLJava_HelloJni_sayHello

7.(JNIEnv*env,jclasscls){

8.printf("HelloWorld/n");

9.}

10.JNIEXPORTjintJNICALLJava_HelloJni_getInt

11.(JNIEnv*env,jobjectthiz){

12.returni;

13.}

14.JNIEXPORTvoidJNICALLJava_HelloJni_setInt

15.(JNIEnv*env,jobjectthiz,jintji){

16.i=ji+1;

17.}

18.JNIEXPORTvoidJNICALLJava_HelloJni_setUser

19.(JNIEnv*env,jobjectthiz,jstringname){

20.jclassuserClass=env->FindClass("User");

21.jmethodIDuserMethod=env->GetMethodID(userClass,"<init>","()V");

22.jfieldIDmId=env->GetFieldID(userClass,"id","J");

23.jfieldIDmUserName=env->GetFieldID(userClass,"userName","Ljava/lang/String;");

24.jfieldIDmIsMan=env->GetFieldID(userClass,"isMan","Z");

25.jfieldIDmAge=env->GetFieldID(userClass,"age","I");

26.jobjectuserObject=env->NewObject(userClass,userMethod);

27.env->SetObjectField(userObject,mUserName,name);

28.env->SetLongField(userObject,mId,1001);

29.env->SetBooleanField(userObject,mIsMan,1);

30.env->SetIntField(userObject,mAge,21);

31.user=userObject;

32.}

#include<iostream>#include<stdio.h>usingnamespacestd;inti=1;jobjectuser;JNIEXPORTvoidJNICALLJava_HelloJni_sayHello(JNIEnv*env,jclasscls){printf("HelloWorld/n");}JNIEXPORTjintJNICALLJava_HelloJni_getInt(JNIEnv*env,jobjectthiz){returni;}JNIEXPORTvoidJNICALLJava_HelloJni_setInt(JNIEnv*env,jobjectthiz,jintji){i=ji+1;}JNIEXPORTvoidJNICALLJava_HelloJni_setUser(JNIEnv*env,jobjectthiz,jstringname){jclassuserClass=env->FindClass("User");jmethodIDuserMethod=env->GetMethodID(userClass,"<init>","()V");jfieldIDmId=env->GetFieldID(userClass,"id","J");jfieldIDmUserName=env->GetFieldID(userClass,"userName","Ljava/lang/String;");jfieldIDmIsMan=env->GetFieldID(userClass,"isMan","Z");jfieldIDmAge=env->GetFieldID(userClass,"age","I");jobjectuserObject=env->NewObject(userClass,userMethod);env->SetObjectField(userObject,mUserName,name);env->SetLongField(userObject,mId,1001);env->SetBooleanField(userObject,mIsMan,1);env->SetIntField(userObject,mAge,21);user=userObject;}

4)有些同学可能会说：“返回个Java对象算什么啊，C/C++和Java之间互传复杂对象才好玩呢！”正所谓“不怕做不到，就怕想不到”，我们接着重构一下上面那个例子!

这次我们传包含有User对象的List到C/C++程序里面

Java代码(User.java)

同上。

Java代码(HelloJni.java)

viewplainprint?

1.importjava.util.*;

2.publicclassHelloJni{

3.static{

4.System.loadLibrary("userbean");

5.}

6.publicnativeintget();

7.publicnativevoidset(inti);

8.publicnativevoidsetUser(StringuserName);

9.publicnativeUsergetUser();

10.publicnativevoidsetUserList(ArrayList<User>userList);

11.publicnativeArrayList<User>getUserList();

12.publicstaticvoidmain(String[]args)

13.{

14.HelloJnihello=newHelloJni();

15.//hello.set(2);

16.//System.out.println(hello.get());

17./*

18.hello.setUser("LiangYaotian");

19.Useruser=hello.getUser();

20.System.out.println("userfromc/c++");

21.System.out.println("name:"+user.getUserName());

22.System.out.println("isMan?:"+user.isMan());

23.System.out.println("age:"+user.getAge());

24.*/

25.ArrayList<User>userList=newArrayList<User>();

26.for(inti=0;i<10;i++){

27.Useru=newUser((long)(1000+i),"LiangYaotian"+i,true,21);

28.userList.add(u);

29.}

30.hello.setUserList(userList);

31.userList=null;

32.userList=hello.getUserList();

33.System.out.println("ArrayList<User>constructfromC++,thenJavaprintit.....");

34.for(Useru:userList){

35.System.out.println("id:"+u.getId()+";name:"+u.getUserName());

36.}

37.}

38.}

importjava.util.*;publicclassHelloJni{static{System.loadLibrary("userbean");}publicnativeintget();publicnativevoidset(inti);publicnativevoidsetUser(StringuserName);publicnativeUsergetUser();publicnativevoidsetUserList(ArrayList<User>userList);publicnativeArrayList<User>getUserList();publicstaticvoidmain(String[]args){HelloJnihello=newHelloJni();//hello.set(2);//System.out.println(hello.get());/*hello.setUser("LiangYaotian");Useruser=hello.getUser();System.out.println("userfromc/c++");System.out.println("name:"+user.getUserName());System.out.println("isMan?:"+user.isMan());System.out.println("age:"+user.getAge());*/ArrayList<User>userList=newArrayList<User>();for(inti=0;i<10;i++){Useru=newUser((long)(1000+i),"LiangYaotian"+i,true,21);userList.add(u);}hello.setUserList(userList);userList=null;userList=hello.getUserList();System.out.println("ArrayList<User>constructfromC++,thenJavaprintit.....");for(Useru:userList){System.out.println("id:"+u.getId()+";name:"+u.getUserName());}}}

C头文件(HelloJni.h)

viewplainprint?

1.#include<jni.h>

2./*HeaderforclassHelloJni*/

3.#ifndef_Included_HelloJni

4.#define_Included_HelloJni

5.#ifdef__cplusplus

6.extern"C"{

7.#endif

8.JNIEXPORTvoidJNICALLJava_HelloJni_sayHello(JNIEnv*,jclass);

9.JNIEXPORTjintJNICALLJava_HelloJni_getInt(JNIEnv*,jobject);

10.JNIEXPORTvoidJNICALLJava_HelloJni_setInt(JNIEnv*,jobject,jint);

11.JNIEXPORTvoidJNICALLJava_HelloJni_setUser(JNIEnv*,jobject,jstring);

12.JNIEXPORTjobjectJNICALLJava_HelloJni_getUser(JNIEnv*,jobject);

#include<jni.h>/*HeaderforclassHelloJni*/#ifndef_Included_HelloJni#define_Included_HelloJni#ifdef__cplusplusextern"C"{#endifJNIEXPORTvoidJNICALLJava_HelloJni_sayHello(JNIEnv*,jclass);JNIEXPORTjintJNICALLJava_HelloJni_getInt(JNIEnv*,jobject);JNIEXPORTvoidJNICALLJava_HelloJni_setInt(JNIEnv*,jobject,jint);JNIEXPORTvoidJNICALLJava_HelloJni_setUser(JNIEnv*,jobject,jstring);JNIEXPORTjobjectJNICALLJava_HelloJni_getUser(JNIEnv*,jobject);

头文件的实现(HelloJni.cpp)

viewplainprint?

1.#include"HelloJni.h"

2.inti=1;

3.jobjectuser;

4.JNIEXPORTjintJNICALLJava_HelloJni_get

5.(JNIEnv*env,jobjectjthiz){

6.printf("HelloWorld/n");

7.}

8.JNIEXPORTvoidJNICALLJava_HelloJni_set

9.(JNIEnv*env,jobjectjthiz,jintji){

10.i=ji+1;

11.}

12.JNIEXPORTvoidJNICALLJava_HelloJni_setUser

13.(JNIEnv*env,jobjectjthiz,jstringname){

14.jclassuserClass=env->FindClass("User");

15.jmethodIDuserMethod=env->GetMethodID(userClass,"<init>","()V");

16.jfieldIDmId=env->GetFieldID(userClass,"id","J");

17.jfieldIDmUserName=env->GetFieldID(userClass,"userName","Ljava/lang/String;");

18.jfieldIDmIsMan=env->GetFieldID(userClass,"isMan","Z");

19.jfieldIDmAge=env->GetFieldID(userClass,"age","I");

20.jobjectuserObject=env->NewObject(userClass,userMethod);

21.env->SetObjectField(userObject,mUserName,name);

22.env->SetLongField(userObject,mId,1001);

23.env->SetBooleanField(userObject,mIsMan,1);

24.env->SetIntField(userObject,mAge,21);

25.user=userObject;

26.}

27.JNIEXPORTjobjectJNICALLJava_HelloJni_getUser

28.(JNIEnv*env,jobjectjthiz){

29.returnuser;

30.}

31.JNIEXPORTvoidJNICALLJava_HelloJni_setUserList

32.(JNIEnv*env,jobjectjthiz,jobjectuserList){

33.inti;

34.//classArrayList

35.jclasscls_arraylist=env->GetObjectClass(userList);

36.//methodinclassArrayList

37.jmethodIDarraylist_get=env->GetMethodID(cls_arraylist,"get","(I)Ljava/lang/Object;");

38.jmethodIDarraylist_size=env->GetMethodID(cls_arraylist,"size","()I");

39.jintlen=env->CallIntMethod(userList,arraylist_size);

40.printf("getjavaArrayList<User>objectbyC++,thenprintit...../n");

41.for(i=0;i<len;i++){

42.jobjectobj_user=env->CallObjectMethod(userList,arraylist_get,i);

43.jclasscls_user=env->GetObjectClass(obj_user);

44.jmethodIDuser_getId=env->GetMethodID(cls_user,"getId","()J");

45.jmethodIDuser_getUserName=env->GetMethodID(cls_user,"getUserName","()Ljava/lang/String;");

46.jmethodIDuser_isMan=env->GetMethodID(cls_user,"isMan","()Z");

47.jmethodIDuser_getAge=env->GetMethodID(cls_user,"getAge","()I");

48.jstringname=(jstring)env->CallObjectMethod(obj_user,user_getUserName);

49.jbooleanb=true;

50.constchar*namePtr=env->GetStringUTFChars(name,&b);

51.jlongid=env->CallLongMethod(obj_user,user_getId);

52.jbooleansex=env->CallBooleanMethod(obj_user,user_isMan);

53.jintage=env->CallIntMethod(obj_user,user_getAge);

54.printf("Id:%d;",id);

55.printf("Name:%s;",namePtr);

56.printf("isMan?%d;",sex);

57.printf("Age:%d/n",age);

58.}

59.}

60.JNIEXPORTjobjectJNICALLJava_HelloJni_getUserList

61.(JNIEnv*env,jobjectjthiz){

62.//ArrayListObject

63.jclasscls_ArrayList=env->FindClass("java/util/ArrayList");

64.jmethodIDconstruct=env->GetMethodID(cls_ArrayList,"<init>","()V");

65.jobjectobj_ArrayList=env->NewObject(cls_ArrayList,construct,"");

66.jmethodIDarrayList_add=env->GetMethodID(cls_ArrayList,"add","(Ljava/lang/Object;)Z");

67.//UserObject

68.jclasscls_user=env->FindClass("User");

69.//noneargumentconstructfunction

70.jmethodIDconstruct_user=env->GetMethodID(cls_user,"<init>","()V");

71.//newaobject

72.jobjectobj_user=env->NewObject(cls_user,construct_user,"");

73.//getmethodid

74./*

75.jmethodIDuser_setId=env->GetMethodID(cls_user,"setId","(J)V");

76.jmethodIDuser_setUserName=env->GetMethodID(cls_user,"setUserName","(Ljava/lang/String;)V");

77.jmethodIDuser_setMan=env->GetMethodID(cls_user,"setMan","(Z)V");

78.jmethodIDuser_setAge=env->GetMethodID(cls_user,"setAge","(I)V");

79.*/

80.inti;

81.for(i=0;i<10;i++){

82.//newaobject

83.jobjectobj_user=env->NewObject(cls_user,construct_user,"");

84.//getfieldid

85.jfieldIDuser_id=env->GetFieldID(cls_user,"id","J");

86.jfieldIDuser_name=env->GetFieldID(cls_user,"userName","Ljava/lang/String;");

87.jfieldIDuser_isMan=env->GetFieldID(cls_user,"isMan","Z");

88.jfieldIDuser_age=env->GetFieldID(cls_user,"age","I");

89.env->SetLongField(obj_user,user_id,i);

90.env->SetObjectField(obj_user,user_name,env->NewStringUTF("LiangYaoTian"));

91.env->SetBooleanField(obj_user,user_isMan,1);

92.env->SetIntField(obj_user,user_age,21);

93.env->CallObjectMethod(obj_ArrayList,arrayList_add,obj_user);

94.}

95.returnobj_ArrayList;

96.}

#include"HelloJni.h"inti=1;jobjectuser;JNIEXPORTjintJNICALLJava_HelloJni_get(JNIEnv*env,jobjectjthiz){printf("HelloWorld/n");}JNIEXPORTvoidJNICALLJava_HelloJni_set(JNIEnv*env,jobjectjthiz,jintji){i=ji+1;}JNIEXPORTvoidJNICALLJava_HelloJni_setUser(JNIEnv*env,jobjectjthiz,jstringname){jclassuserClass=env->FindClass("User");jmethodIDuserMethod=env->GetMethodID(userClass,"<init>","()V");jfieldIDmId=env->GetFieldID(userClass,"id","J");jfieldIDmUserName=env->GetFieldID(userClass,"userName","Ljava/lang/String;");jfieldIDmIsMan=env->GetFieldID(userClass,"isMan","Z");jfieldIDmAge=env->GetFieldID(userClass,"age","I");jobjectuserObject=env->NewObject(userClass,userMethod);env->SetObjectField(userObject,mUserName,name);env->SetLongField(userObject,mId,1001);env->SetBooleanField(userObject,mIsMan,1);env->SetIntField(userObject,mAge,21);user=userObject;}JNIEXPORTjobjectJNICALLJava_HelloJni_getUser(JNIEnv*env,jobjectjthiz){returnuser;}JNIEXPORTvoidJNICALLJava_HelloJni_setUserList(JNIEnv*env,jobjectjthiz,jobjectuserList){inti;//classArrayListjclasscls_arraylist=env->GetObjectClass(userList);//methodinclassArrayListjmethodIDarraylist_get=env->GetMethodID(cls_arraylist,"get","(I)Ljava/lang/Object;");jmethodIDarraylist_size=env->GetMethodID(cls_arraylist,"size","()I");jintlen=env->CallIntMethod(userList,arraylist_size);printf("getjavaArrayList<User>objectbyC++,thenprintit...../n");for(i=0;i<len;i++){jobjectobj_user=env->CallObjectMethod(userList,arraylist_get,i);jclasscls_user=env->GetObjectClass(obj_user);jmethodIDuser_getId=env->GetMethodID(cls_user,"getId","()J");jmethodIDuser_getUserName=env->GetMethodID(cls_user,"getUserName","()Ljava/lang/String;");jmethodIDuser_isMan=env->GetMethodID(cls_user,"isMan","()Z");jmethodIDuser_getAge=env->GetMethodID(cls_user,"getAge","()I");jstringname=(jstring)env->CallObjectMethod(obj_user,user_getUserName);jbooleanb=true;constchar*namePtr=env->GetStringUTFChars(name,&b);jlongid=env->CallLongMethod(obj_user,user_getId);jbooleansex=env->CallBooleanMethod(obj_user,user_isMan);jintage=env->CallIntMethod(obj_user,user_getAge);printf("Id:%d;",id);printf("Name:%s;",namePtr);printf("isMan?%d;",sex);printf("Age:%d/n",age);}}JNIEXPORTjobjectJNICALLJava_HelloJni_getUserList(JNIEnv*env,jobjectjthiz){//ArrayListObjectjclasscls_ArrayList=env->FindClass("java/util/ArrayList");jmethodIDconstruct=env->GetMethodID(cls_ArrayList,"<init>","()V");jobjectobj_ArrayList=env->NewObject(cls_ArrayList,construct,"");jmethodIDarrayList_add=env->GetMethodID(cls_ArrayList,"add","(Ljava/lang/Object;)Z");//UserObjectjclasscls_user=env->FindClass("User");//noneargumentconstructfunctionjmethodIDconstruct_user=env->GetMethodID(cls_user,"<init>","()V");//newaobjectjobjectobj_user=env->NewObject(cls_user,construct_user,"");//getmethodid/*jmethodIDuser_setId=env->GetMethodID(cls_user,"setId","(J)V");jmethodIDuser_setUserName=env->GetMethodID(cls_user,"setUserName","(Ljava/lang/String;)V");jmethodIDuser_setMan=env->GetMethodID(cls_user,"setMan","(Z)V");jmethodIDuser_setAge=env->GetMethodID(cls_user,"setAge","(I)V");*/inti;for(i=0;i<10;i++){//newaobjectjobjectobj_user=env->NewObject(cls_user,construct_user,"");//getfieldidjfieldIDuser_id=env->GetFieldID(cls_user,"id","J");jfieldIDuser_name=env->GetFieldID(cls_user,"userName","Ljava/lang/String;");jfieldIDuser_isMan=env->GetFieldID(cls_user,"isMan","Z");jfieldIDuser_age=env->GetFieldID(cls_user,"age","I");env->SetLongField(obj_user,user_id,i);env->SetObjectField(obj_user,user_name,env->NewStringUTF("LiangYaoTian"));env->SetBooleanField(obj_user,user_isMan,1);env->SetIntField(obj_user,user_age,21);env->CallObjectMethod(obj_ArrayList,arrayList_add,obj_user);}returnobj_ArrayList;}

运行结果：

theEnd.jpg

源码：E-Mail我：[email protected]

原创作品，转载需注明出处...http://blog.csdn.net/u_xtian/archive/2010/11/25/6033963.aspx