example/src/main/java/com/fr/function/BinaryImage.java

package com.fr.function;

import com.fr.data.core.db.BinaryObject;
import com.fr.script.AbstractFunction;
import com.sun.jna.Library;
import com.sun.jna.Native;

import javax.imageio.ImageIO;
import java.awt.image.BufferedImage;
import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;

public class BinaryImage extends AbstractFunction {

    //加载dll，"E:\\bmp\\WltRS"是dll的文件完整路径，但不带后缀名，生成WltRS.class
    static WltRS wltrs = (WltRS) Native.loadLibrary("E:\\bmp\\WltRS", WltRS.class);

    static int index = 0;

    public Object run(Object[] args) {

        int current = index;

        //args[0] 是 BinaryObject对象，取为bo
        BinaryObject bo = (BinaryObject) args[0];

        //将bo转换为.wlt文件，并保存在位置E:\bmp\；本地方法GetBmp的第一个参数是wlt文件的路径
        getFile(bo.getBytes(), "E:\\bmp\\", current + ".wlt");

        //读取.wlt为文件
        File file = new File("E:\\bmp\\" + current + ".wlt");

        //调用本地方法，在相同路径下生产.bmp
        wltrs.GetBmp("E:\\bmp\\" + current + ".wlt", 1);

        //读取并返回图片
        File imagefile = new File("E:\\bmp\\" + current + ".bmp");
        BufferedImage buffer = null;
        try {
            buffer = ImageIO.read(imagefile);
        } catch (IOException e) {
            e.printStackTrace();
        }

        index = (++index) % 300;
        return buffer;
    }


    // byte[]转换为file的方法
    public static void getFile(byte[] bfile, String filePath, String fileName) {
        BufferedOutputStream bos = null;
        FileOutputStream fos = null;
        File file = null;
        try {
            File dir = new File(filePath);
            if (!dir.exists() && dir.isDirectory()) {//判断文件目录是否存在
                dir.mkdirs();
            }
            file = new File(filePath + "\\" + fileName);
            fos = new FileOutputStream(file);
            bos = new BufferedOutputStream(fos);
            bos.write(bfile);
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            if (bos != null) {
                try {
                    bos.close();
                } catch (IOException e1) {
                    e1.printStackTrace();
                }
            }
            if (fos != null) {
                try {
                    fos.close();
                } catch (IOException e1) {
                    e1.printStackTrace();
                }
            }
        }
    }
}

//用jna调用本地方法的必须步骤，具体含义不明
interface WltRS extends Library {
    //定义要调用的本地方法
    void GetBmp(String str, int i);
}