java 读取图片色深

import java.io.File;

public class getinfo {
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        String url;
        if (args.length != 0) {
            url = args[0];
        } else
            url = "F:\\tmpxu\\333.png";
        File f1 = new File(url);// "F:\\tmpxu\\333.png"
        methodclass my = new methodclass();
        my.ImageInfo(f1);
        System.out.println("getName====" + my.getName());
        System.out.println("getPath====" + my.getPath());
        System.out.println("getDate_created====" + my.getDate_created());
        System.out.println("getDate_modified====" + my.getDate_modified());
        System.out.println("getType====" + my.getType());
        System.out.println("getSize====" + my.getSize());
        System.out.println("getWidth====" + my.getWidth());
        System.out.println("getHeight====" + my.getHeight());
        System.out.println("getBit_depth====" + my.getBit_depth());
    }
}

import java.awt.image.BufferedImage;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.text.DecimalFormat;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.StringTokenizer;
import javax.imageio.ImageIO;

public class methodclass {
    private String name = "";
    private String path = "";
    private String date_created = "";
    private String date_modified = "";
    private String bytes = "";
    private String type = "";
    private String size = "";
    private String width = "";
    private String height = "";
    private String bit_depth = "";

    public void ImageInfo(File file) {
        name = file.getName();
        path = file.getParent();
        date_created = getDate_created(file);
        date_modified = new SimpleDateFormat("yyyy/MM/dd HH:mm")
                .format(new Date(file.lastModified()));
        bytes = getBytes(file);
        getImageData(file);
        getImageFileData(file);
    }

    // 判读图片类型
    private void getImageFileData(File file) {
        try {
            FileInputStream input = new FileInputStream(file);
            /*
             * he java.io.FileInputStream.available() method returns number of
             * remaining bytes that can be read from this input stream without
             * blocking by the next method call for this input stream. The next
             * method call can also be the another thread.
             * 通过available方法取得流的最大字符数
             */
            byte[] b = new byte[input.available()];
            if (b.length == 0) {
                System.out.print("the file is empty!!!");
                return;
            }
            input.read(b);
            input.close();
            int b1 = b[0] & 0xff;
            int b2 = b[1] & 0xff;
            if (b1 == 0x42 && b2 == 0x4d) {
                checkBmp(b);
            } else if (b1 == 0x47 && b2 == 0x49) {
                checkGif(b);
            } else if (b1 == 0x89 && b2 == 0x50) {
                checkPng(b);
            } else if (b1 == 0xff && b2 == 0xd8) {
                checkJpeg(b, file);
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    // 获得图片宽高
    private void getImageData(File file) {
        try {
            BufferedImage img = ImageIO.read(file);
            size = img.getWidth() + " x " + img.getHeight();
            width = img.getWidth() + " 像素";
            height = img.getHeight() + " 像素";
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    public void checkBmp(byte[] b) {
        type = "BMP 文件";
        int bitsPerPixel = (b[28] & 0xff) | (b[29] & 0xff) << 8;
        if (bitsPerPixel == 1 || bitsPerPixel == 4 || bitsPerPixel == 8
                || bitsPerPixel == 16 || bitsPerPixel == 24
                || bitsPerPixel == 32) {
            bit_depth = bitsPerPixel + "";
        }
    }

    public void checkGif(byte[] b) {
        type = "GIF 文件";
        bit_depth = (b[10] & 0x07) + 1 + "";
    }

    public void checkPng(byte[] b) {
        type = "PNG 图像";
        int bitsPerPixel = b[24] & 0xff;
        if ((b[25] & 0xff) == 2) {
            bitsPerPixel *= 3;
        } else if ((b[25] & 0xff) == 6) {
            bitsPerPixel *= 4;
        }
        bit_depth = bitsPerPixel + "";
    }

    /*
     * (b[i] & 0xff):byte转换int时的运算 其原因在于:1.byte的大小为8bits而int的大小为32bits；
     * 2.java的二进制采用的是补码形式；
     * 如果不进行&0xff，那么当一个byte会转换成int时，由于int是32位，而byte只有8位这时会进行补位，
     * 例如补码11111111的十进制数为-1转换为int时变为32个1！和0xff相与后，高24比特就会被清0了，结果就对了。 bit_depth：
     * a 1 bit image, can only show two colors, black and white. That is because
     * the 1 bit can only store one of two values, 0 (white) and 1 (black). An 8
     * bit image can store 256 possible colors, while a 24 bit image can display
     * about 16 million colors.
     */
    public void checkJpeg(byte[] b, File file) {
        type = "JPEG 图像";
        int i = 2;
        while (true) {
            int marker = (b[i] & 0xff) << 8 | (b[i + 1] & 0xff);
            int size = (b[i + 2] & 0xff) << 8 | (b[i + 3] & 0xff);
            if (marker >= 0xffc0 && marker <= 0xffcf && marker != 0xffc4
                    && marker != 0xffc8) {
                bit_depth = (b[i + 4] & 0xff) * (b[i + 9] & 0xff) + "";
                break;
            } else {
                i += size + 2;
            }
        }
    }

    // 文件创建日期
    private String getDate_created(File file) {
        try {
            Process ls_proc = Runtime.getRuntime().exec(
                    "cmd.exe /c dir \"" + file.getAbsolutePath() + "\" /tc");
            BufferedReader reader = new BufferedReader(new InputStreamReader(
                    ls_proc.getInputStream()));
            for (int i = 0; i < 5; i++) {
                reader.readLine();
            }
            StringTokenizer st = new StringTokenizer(reader.readLine());
            String date = st.nextToken();
            String time = st.nextToken();
            reader.close();
            return date + " " + time;
        } catch (IOException e) {
            e.printStackTrace();
        }
        return "";
    }

    // 读取文件大小
    private String getBytes(File file) {
        DecimalFormat df = new DecimalFormat();
        float length = (float) file.length();
        int p = 0;
        while (length > 1023) {
            length /= 1024;
            p++;
        }
        if (length > 99) {
            df.setMaximumFractionDigits(0);
        } else if (length > 9) {
            df.setMaximumFractionDigits(1);
        } else {
            df.setMaximumFractionDigits(2);
        }
        if (p == 0) {
            return (int) length + " 字节";
        } else if (p == 1) {
            return df.format(length) + " KB";
        } else if (p == 2) {
            return df.format(length) + " MB";
        } else if (p == 3) {
            return df.format(length) + " GB";
        } else {
            return df.format(length) + " TB";
        }
    }

    public String getName() {
        return name;
    }

    public String getPath() {
        return path;
    }

    public String getDate_created() {
        return date_created;
    }

    public String getDate_modified() {
        return date_modified;
    }

    public String getBytes() {
        return bytes;
    }

    public String getType() {
        return type;
    }

    public String getSize() {
        return size;
    }

    public String getWidth() {
        return width;
    }

    public String getHeight() {
        return height;
    }

    public String getBit_depth() {
        return bit_depth;
    }
}