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Swig java Jni開發(fā)指南
目錄
Swig java Jni開發(fā)指南

Swig參考文檔
全局變量
常量
只讀變量
枚舉
函數(shù)
結(jié)構(gòu)體
類
調(diào)用函數(shù)指針
回調(diào)
類型轉(zhuǎn)換
兩個常用命令

簡介：
JNI：Java Native Interface，它允許Java代碼和其他語言（尤其C/C++）寫的代碼進行交互，只要遵守調(diào)用約定即可。
JNA：Java Native Access是一個開源的Java框架，是Sun公司推出的一種調(diào)用本地方法的技術(shù)，是建立在經(jīng)典的JNI基礎(chǔ)之上的一個框架。之所以說它是JNI的替代者，是因為JNA大大簡化了調(diào)用本地方法的過程，使用很方便，基本上不需要脫離Java環(huán)境就可以完成。
Swig可以根據(jù)c或c++代碼生成jni代碼的工具，大大簡化jni的開發(fā)
Jnaerator可以根據(jù)c或c++代碼生成jna代碼的工具，大大簡化jna的開發(fā)
從難易度看，使用jnaerator開發(fā)jna最簡單，代碼基本都是自動生成，但是jna開發(fā)有個很大的缺點，就是如果c代碼過于復(fù)雜，比如出現(xiàn)java調(diào)用c，然后c再回調(diào)java，java返回的結(jié)果c還需要繼續(xù)處理的時候，經(jīng)常出現(xiàn)不可控制的crash，而jna算是中間層，這個層出現(xiàn)的錯誤完全無法調(diào)試，被逼無奈，我們的項目先用jna開發(fā)，不得不轉(zhuǎn)jni開發(fā)，在使用swig的過程中，也遇到不少問題，因此總結(jié)如下：

Swig參考文檔
http://www.swig.org/Doc3.0/SWIGDocumentation.html
swig是一個編譯時軟件開發(fā)工具，它能生成將用c/c++編寫的原生模塊與包括java在內(nèi)的其他編程語言進行鏈接的必要代碼。Swig不僅是一個代碼生成器，還是一個接口編譯器。它不定義新的協(xié)議，也不是一個組件框架或者一個特定的運行時庫。Swig把接口文件看做輸入，并生成必要的代碼在java中展示接口，從而讓java能夠理解原生代碼中的接口定義。Swig不是一個存根生成器；它產(chǎn)生將要被編譯和運行的代碼。
Swig可應(yīng)用于包括windows、mac os x和linux在內(nèi)的大多數(shù)操作系統(tǒng)平臺。大家可以參考官網(wǎng)文檔安裝。
使用swig需要生成一個.i的接口文件，swig接口文件包含函數(shù)原型、類和變量聲明，它的語法和普通的c/c++頭文件一樣。除了c/c++關(guān)鍵字和預(yù)處理器指令，接口文件還包含swig特有的預(yù)處理器指令，該指令可用于優(yōu)化生成封裝代碼。
全局變量
a) 編寫example.h

int counter = 0;

b) 編寫example.i

%module example  
%{  
#include "example.h"  
%}  
  
extern int counter;

c) 編寫runme.java

/ runme.java  
 
ublic class runme {  
 static {  
   System.loadLibrary("example");  
 }  
 
 public static void main(String argv[]) {  
   System.out.println(example.getCounter());  
   example.setCounter(1);  
   System.out.println(example.getCounter());  
 }

d) 執(zhí)行以下命令

swig -java example.i  
gcc -Wall -Wl,--kill-at -I "%JAVA_HOME%/include" -I "%JAVA_HOME%/include/win32" -shared -s -o example.dll *.c  
javac -d . *.java  
java -cp . runme

常量
a) 編寫example.i

%module example  
  
/* 用define指令定義常量 */  
#define MAX_WIDTH 640  
/* 用%constant指令定義常量 */  
%constant int MAX_HEIGHT = 320;

b) 編寫runme.java

// runme.java  
  
public class runme {  
  static {  
    System.loadLibrary("example");  
  }  
  
  public static void main(String argv[]) {  
    System.out.println(example.MAX_WIDTH);  
        System.out.println(example.MAX_HEIGHT);  
      }  
    }

c) 執(zhí)行以下命令，同1.d

只讀變量
區(qū)別只是在生成的包裝類中，只讀的只有g(shù)et函數(shù)，讀寫的有g(shù)et和set函數(shù)
a) 編寫example.h

/* 只讀變量 */  
int readOnly;  
  
/* 讀-寫變量 */  
int readWrite;

b) 編寫example.i

%module example  
%{  
#include "example.h"  
%}  
  
/* 只讀變量 */  
%immutable readOnly;  
int readOnly;  
  
/* 讀-寫變量 */  
int readWrite;

c) 編寫runme.java

// runme.java  
  
public class runme {  
  static {  
    System.loadLibrary("example");  
  }  
  
  public static void main(String argv[]) {  
    System.out.println(example.getReadOnly());  
    example.setReadWrite(10);  
    System.out.println(example.getReadWrite());  
  }  
}

d) 執(zhí)行以下命令，同1.d

枚舉
a) 編寫example.h

/* 匿名枚舉 */  
enum {ONE = 1, TWO = 2, THREE, FOUR};  
/* 命名枚舉 */  
enum Color { RED = 1, GREEN, BLANK, YELLOW};  
  
enum SeasonEnum{ SPRING = 1,SUMMER,AUTUMN,WINTER};

b) 編寫example.i

%module example  
%{  
#include "example.h"  
%}  
  
/* 匿名枚舉 */
enum {ONE = 1, TWO = 2, THREE, FOUR};  
/* 命名枚舉 */  
enum Color { RED = 1, GREEN, BLANK, YELLOW};  
/* 類型不安全，這個用起來最簡單 */  
%include "enumtypeunsafe.swg"  
%javaconst(1);  
enum SeasonEnum{ SPRING = 1,SUMMER,AUTUMN,WINTER};

c) 編寫runme.java

// runme.java  
  
public class runme {  
  static {  
    System.loadLibrary("example");  
  }  
  
  public static void main(String argv[]) {  
    System.out.println(example.ONE + "," + example.TWO + "," + example.THREE + "," + example.FOUR);  
    System.out.println(Color.RED.swigValue() + "," + Color.GREEN.swigValue() + "," + Color.BLANK.swigValue() + "," + Color.YELLOW.swigValue());  
    System.out.println(SeasonEnum.SPRING + "," + SeasonEnum.SUMMER + "," + SeasonEnum.AUTUMN + "," + SeasonEnum.WINTER);  
  }  
}

d) 執(zhí)行以下命令，同1.d

函數(shù)
這里直接抄swigwin-3.0.12\Examples\java\simple
a) 編寫example.c

/* File : example.c */  
  
/* A global variable */  
double Foo = 3.0;  
  
/* Compute the greatest common divisor of positive integers */  
int gcd(int x, int y) {  
  int g;  
  g = y;  
  while (x > 0) {  
    g = x;  
    x = y % x;  
    y = g;  
  }  
  return g;  
}

b) 編寫example.i

/* File : example.i */  
%module example  
  
%inline %{  
extern int    gcd(int x, int y);  
extern double Foo;  
%}

c) 編寫runme.java

public class runme {  
  
  static {  
    try {  
    System.loadLibrary("example");  
    } catch (UnsatisfiedLinkError e) {  
      System.err.println("Native code library failed to load. See the chapter on Dynamic Linking Problems in the SWIG Java documentation for help.\n" + e);  
      System.exit(1);  
    }  
  }  
  
  public static void main(String argv[]) {  
    // Call our gcd() function  
      
    int x = 42;  
    int y = 105;  
    int g = example.gcd(x,y);  
    System.out.println("The gcd of " + x + " and " + y + " is " + g);  
      
    // Manipulate the Foo global variable  
      
    // Output its current value  
    System.out.println("Foo = " + example.getFoo());  
      
    // Change its value  
    example.setFoo(3.1415926);  
      
    // See if the change took effect  
    System.out.println("Foo = " + example.getFoo());  
  }  
}

d) 執(zhí)行以下命令，同1.d

結(jié)構(gòu)體
a) 編寫example.h

// example.h  
  
struct Books  
{  
   char  title[50];  
   char  author[50];  
   char  subject[100];  
   int   book_id;  
};  
  
extern void show(struct Books* book);

b) 編寫example.c

// example.c  
#include <stdio.h>  
#include "example.h"  
  
// struct Books book = {"C 語言", "RUNOOB", "編程語言", 123456};  
void show(struct Books* book)  
{  
    printf("title : %s\nauthor: %s\nsubject: %s\nbook_id: %d\n", book->title, book->author, book->subject, book->book_id);  
}

c) 編寫example.i

/* File : example.i */  
%module example  
  
%{  
#include "example.h"  
%}  
  
%include "example.h"

d) 編寫runme.java

// runme.java  
  
public class runme {  
  static {  
    System.loadLibrary("example");  
  }  
  
  public static void main(String argv[]) {  
      
    Books book = new Books();  
    book.setTitle("C 語言");  
    book.setAuthor("RUNOOB");  
    book.setSubject("編程語言");  
    book.setBook_id(123456);  
      
    example.show(book);  
  }  
}

e) 執(zhí)行以下命令，同1.d

類
這里直接抄swigwin-3.0.12\Examples\java\ class，對比java調(diào)用c的結(jié)構(gòu)體來看，兩個的處理完全一樣，都是把c的結(jié)構(gòu)或類包裝成java類使用
a) 編寫example.h

/* File : example.h */  
  
class Shape {  
public:  
  Shape() {  
    nshapes++;  
  }  
  virtual ~Shape() {  
    nshapes--;  
  }  
  double  x, y;  
  void    move(double dx, double dy);  
  virtual double area() = 0;  
  virtual double perimeter() = 0;  
  static  int nshapes;  
};  
  
class Circle : public Shape {  
private:  
  double radius;  
public:  
  Circle(double r) : radius(r) { }  
  virtual double area();  
  virtual double perimeter();  
};  
  
class Square : public Shape {  
private:  
  double width;  
public:  
  Square(double w) : width(w) { }  
  virtual double area();  
  virtual double perimeter();  
};

b) 編寫example.cxx

/* File : example.cxx */  
  
#include "example.h"  
#define M_PI 3.14159265358979323846  
  
/* Move the shape to a new location */  
void Shape::move(double dx, double dy) {  
  x += dx;  
  y += dy;  
}  
  
int Shape::nshapes = 0;  
  
double Circle::area() {  
  return M_PI*radius*radius;  
}  
  
double Circle::perimeter() {  
  return 2*M_PI*radius;  
}  
  
double Square::area() {  
  return width*width;  
}  
  
double Square::perimeter() {  
  return 4*width;  
}

c) 編寫example.i

/* File : example.i */  
%module example  
  
%{  
#include "example.h"  
%}  
  
/* Let's just grab the original header file here */  
%include "example.h"

d) 編寫runme.java

// This example illustrates how C++ classes can be used from Java using SWIG.  
// The Java class gets mapped onto the C++ class and behaves as if it is a Java class.  
  
public class runme {  
  static {  
    try {  
        System.loadLibrary("example");  
    } catch (UnsatisfiedLinkError e) {  
      System.err.println("Native code library failed to load. See the chapter on Dynamic Linking Problems in the SWIG Java documentation for help.\n" + e);  
      System.exit(1);  
    }  
  }  
  
  public static void main(String argv[])   
  {  
    // ----- Object creation -----  
      
    System.out.println( "Creating some objects:" );  
    Circle c = new Circle(10);  
    System.out.println( "    Created circle " + c );  
    Square s = new Square(10);  
    System.out.println( "    Created square " + s );  
      
    // ----- Access a static member -----  
      
    System.out.println( "\nA total of " + Shape.getNshapes() + " shapes were created" );  
      
    // ----- Member data access -----  
      
    // Notice how we can do this using functions specific to  
    // the 'Circle' class.  
    c.setX(20);  
    c.setY(30);  
      
    // Now use the same functions in the base class  
    Shape shape = s;  
    shape.setX(-10);  
    shape.setY(5);  
      
    System.out.println( "\nHere is their current position:" );  
    System.out.println( "    Circle = (" + c.getX() + " " + c.getY() + ")" );  
    System.out.println( "    Square = (" + s.getX() + " " + s.getY() + ")" );  
      
    // ----- Call some methods -----  
      
    System.out.println( "\nHere are some properties of the shapes:" );  
    Shape[] shapes = {c,s};  
    for (int i=0; i<shapes.length; i++)  
    {  
          System.out.println( "   " + shapes[i].toString() );  
          System.out.println( "        area      = " + shapes[i].area() );  
          System.out.println( "        perimeter = " + shapes[i].perimeter() );  
    }  
      
    // Notice how the area() and perimeter() functions really  
    // invoke the appropriate virtual method on each object.  
      
    // ----- Delete everything -----  
      
    System.out.println( "\nGuess I'll clean up now" );  
      
    // Note: this invokes the virtual destructor  
    // You could leave this to the garbage collector  
    c.delete();  
    s.delete();  
      
    System.out.println( Shape.getNshapes() + " shapes remain" );  
    System.out.println( "Goodbye" );  
  }  
}

e) 執(zhí)行以下命令

swig -c++ -java example.i  
g++ -Wall -Wl,--kill-at -I "%JAVA_HOME%/include" -I "%JAVA_HOME%/include/win32" -shared -s -o example.dll *.cxx  
javac -d . *.java  
java -cp . runme

調(diào)用函數(shù)指針
重點：這個只能獲得函數(shù)指針，然后多寫個函數(shù)把函數(shù)指針傳遞給c層來調(diào)用，java層沒有找到方法調(diào)用
這種方法會出現(xiàn)一些比較奇怪的類名，例如：SWIGTYPE_p_f_float_float__float，為了類名可讀，可以用下一部分說的回調(diào)來處理，只是不需要java繼承，直接get出來，然后調(diào)用run就可以用了
a) 編寫example.h

/**************************************** 
 * 函數(shù)指針結(jié)構(gòu)體 
 ***************************************/  
typedef float (*callback_t)(float a, float b);  
  
typedef struct _OP {  
    callback_t p_add;   
    callback_t p_sub;   
    callback_t p_mul;   
    callback_t p_div;   
} OP;   
  
extern OP* get_init_op(void);  
extern float add_sub_mul_div(float a, float b, callback_t fun);

b) 編寫example.i

/* File : example.i */  
%module example  
%{  
#include "example.h"  
%}  
  
%include "example.h"

c) 編寫example.c

#include <stdio.h>  
#include <stdlib.h>  
#include "example.h"  
  
/**************************************** 
 * 加減乘除函數(shù) 
 ***************************************/  
float ADD(float a, float b)   
{  
    return a + b;  
}  
  
float SUB(float a, float b)   
{  
    return a - b;  
}  
  
float MUL(float a, float b)   
{  
    return a * b;  
}  
  
float DIV(float a, float b)   
{  
    return a / b;  
}  
  
/**************************************** 
 * 初始化函數(shù)指針 
 ***************************************/  
OP* get_init_op(void)  
{  
        OP *op = (OP *)malloc(sizeof(OP));   
    op->p_add = ADD;  
    op->p_sub = SUB;  
    op->p_mul = MUL;  
    op->p_div = DIV;  
    return op;  
}  
  
/**************************************** 
 * 庫函數(shù) 
 ***************************************/  
float add_sub_mul_div(float a, float b, callback_t fun)  
{  
    return fun(a, b);  
}  
  
int main()   
{  
    OP *op = get_init_op();   
          
    /* 直接使用函數(shù)指針調(diào)用函數(shù) */   
    printf("ADD = %f, SUB = %f, MUL = %f, DIV = %f\n", (op->p_add)(1.3, 2.2), (*op->p_sub)(1.3, 2.2),   
            (op->p_mul)(1.3, 2.2), (*op->p_div)(1.3, 2.2));  
       
    /* 調(diào)用回調(diào)函數(shù) */   
    printf("ADD = %f, SUB = %f, MUL = %f, DIV = %f\n",   
            add_sub_mul_div(1.3, 2.2, ADD),   
            add_sub_mul_div(1.3, 2.2, SUB),   
            add_sub_mul_div(1.3, 2.2, MUL),   
            add_sub_mul_div(1.3, 2.2, DIV));  
  
    return 0;   
}

d) 編寫runme.java

// runme.java  
  
public class runme {  
  static {  
    System.loadLibrary("example");  
  }  
  
  public static void main(String argv[]) {  
      
    OP op = example.get_init_op();  
  
    System.out.println(example.add_sub_mul_div(1.3f, 2.2f,op.getP_add()));  
    System.out.println(example.add_sub_mul_div(1.3f, 2.2f,op.getP_sub()));  
    System.out.println(example.add_sub_mul_div(1.3f, 2.2f,op.getP_mul()));  
    System.out.println(example.add_sub_mul_div(1.3f, 2.2f,op.getP_div()));  
  }  
}

e) 執(zhí)行以下命令，同1.d

回調(diào)
這個c代碼搞不定，只能通過c++類實現(xiàn)，參考上例修改實現(xiàn)
參考：swigwin-3.0.12\Examples\java\callback
a) 編寫example.h

class Callback {  
public:  
    virtual ~Callback() {}  
    virtual float run(float a, float b) {return 0;}  
};  
  
class OP {  
public:  
    Callback *p_add;  
    Callback *p_sub;  
    Callback *p_mul;  
    Callback *p_div;  
      
public:  
    OP(): p_add(0),p_sub(0),p_mul(0),p_div(0) {}  
    ~OP() {   
    }  
      
    float add_sub_mul_div(float a, float b, Callback* fun) {  
        if(fun != NULL) {  
            return fun->run(a, b);  
        }  
        printf("add_sub_mul_div error\n");  
        return 0;  
    }  
};

b) 編寫example.i
重點：這里必須設(shè)置%module(directors="1") example
并且指定回調(diào)類：
%feature("director") Callback;

/* File : example.i */  
%module(directors="1") example  
%{  
#include "example.h"  
%}  
  
%feature("director") Callback;  
%include "example.h"

c) 編寫runme.java

// runme.java  
  
public class runme {  
  static {  
    System.loadLibrary("example");  
  }  
  
  public static void main(String argv[]) {  
      
    OP op = new OP();  
    op.setP_add(new JavaCallbackAdd());  
    op.setP_sub(new JavaCallbackSub());  
    op.setP_mul(new JavaCallbackMul());  
    op.setP_div(new JavaCallbackDiv());  
  
    System.out.println(op.add_sub_mul_div(1.3f, 2.2f,op.getP_add()));  
    System.out.println(op.add_sub_mul_div(1.3f, 2.2f,op.getP_sub()));  
    System.out.println(op.add_sub_mul_div(1.3f, 2.2f,op.getP_mul()));  
    System.out.println(op.add_sub_mul_div(1.3f, 2.2f,op.getP_div()));  
      
    System.out.println(op.getP_add().run(1.3f, 2.2f));  
    System.out.println(op.getP_sub().run(1.3f, 2.2f));  
    System.out.println(op.getP_mul().run(1.3f, 2.2f));  
    System.out.println(op.getP_div().run(1.3f, 2.2f));  
      
  }  
}  
  
  
class JavaCallbackAdd extends Callback  
{  
  public float run(float a, float b) {  
    return a + b;  
  }  
}  
  
class JavaCallbackSub extends Callback  
{  
  public float run(float a, float b) {  
    return a - b;  
  }  
}  
  
class JavaCallbackMul extends Callback  
{  
  public float run(float a, float b) {  
    return a * b;  
  }  
}  
  
class JavaCallbackDiv extends Callback  
{  
  public float run(float a, float b) {  
    return a / b;  
  }  
}

d) 執(zhí)行以下命令

swig -c++ -java example.i  
g++ -Wall -Wl,--kill-at -I "%JAVA_HOME%/include" -I "%JAVA_HOME%/include/win32" -shared -s -o example.dll *.cxx  
javac -d . *.java  
java -cp . runme

類型轉(zhuǎn)換
a) 錯誤的情況
C函數(shù)包裝

%module example  
  
int add_option(const unsigned char *data);

得到的包裝函數(shù)：
public static int add_option(SWIGTYPE_p_unsigned_char data)
其中SWIGTYPE_p_unsigned_char完全無法賦值，也就是無法使用
b) 正確的處理

%module example  
  
%include <arrays_java.i>  
%apply signed char *INOUT { unsigned char * };  
%apply signed char[] { const unsigned char * };  
  
int add_option(const unsigned char *data);

這樣就可以得到包裝函數(shù)：
public static int add_option(byte[] data)
c) 更多的類型轉(zhuǎn)換

%include "typemaps.i"  
%include "stdint.i"  
%include "arrays_java.i"  
%include "carrays.i"  
  
typedef int8_t Int8;  
typedef uint8_t Uint8;  
typedef int16_t Int16;  
typedef uint16_t Uint16;  
typedef uint32_t Int32;  
typedef uint32_t Uint32;

兩個常用命令
a) Javah
javah –jni Java類名，可以通過java類生成.h 頭文件
b) javap
javap -s -p Java類名
用來輸出一個Java類的方法的簽名，用于c調(diào)用java類獲得methid的時候使用

三个男躁一个女,国精产品一区一手机的秘密,麦子交换系列最经典十句话,欧美国产综合欧美视频

2019-04-08 Swig java Jni開發(fā)指南

2019-04-08 Swig java Jni開發(fā)指南

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三个男躁一个女,国精产品一区一手机的秘密,麦子交换系列最经典十句话,欧美 国产 综合 欧美 视频

2019-04-08 Swig java Jni開發(fā)指南

推薦閱讀更多精彩內(nèi)容

三个男躁一个女,国精产品一区一手机的秘密,麦子交换系列最经典十句话,欧美国产综合欧美视频