JavaWeb实现裁剪图片上传完整代码-eolink官网

JavaWeb实现裁剪图片上传完整代码

本文实例为大家分享了javaWeb实现裁剪图片上传完整案例，供大家参考，具体内容如下

实现思路

•使用jcrop插件手机要裁剪图片的坐标

•将收集到的参数传递到后台，在后台使用java图形对象绘制图像进行裁剪

◦后台处理流程：

1、将上传的图片按按照比例进行压缩后上传到文件服务器，并且将压缩后的图片保存在本地临时目录中。

2、将压缩后的图片回显到页面，使用jcrop进行裁剪，手机裁剪坐标（x,y,width,height）

■@paramx 目标切片起点坐标X

■@param y 目标切片起点坐标Y

■@param width 目标切片宽度

■@param height 目标切片高度

3、后台处理裁剪裁剪，重新上传

jsp页面

<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>

<%@ page contentType="text/html;charset=UTF-8" language="java" %>

上传头像

支持jpg、png格式

图片小于2M

重新上传

400 x 300像素

<%--

80 x 80像素

拖拽或缩放，生成自己满意的头像

<%--

保存头像

后台java代码

图片上传工具类

package com.shengya.service.utils;

import com.shengya.service.ImgContants;

import org.apache.commons.fileupload.disk.DiskFileItem;

import org.springframework.web.multipart.MultipartFile;

import org.springframework.web.multipart.commons.CommonsMultipartFile;

import sun.misc.BASE64Encoder;

import javax.crypto.Mac;

import javax.crypto.SecretKey;

import javax.crypto.spec.SecretKeySpec;

import javax.imageio.ImageIO;

import javax.imageio.ImageReadParam;

import java.awt.*;

import java.awt.geom.AffineTransform;

import java.awt.image.AffineTransformOp;

import java.awt.image.BufferedImage;

import java.io.*;

import java.net.HttpURLConnection;

import java.net.URL;

import java.net.URLEncoder;

import java.util.ArrayList;

/**

* @author Darcy

* Created by Administrator on 2016/6/17.

public class UploadUtils {

// public final static String RADIOURL = "http://211.102.216.237:8011/fileServer/webapi/Attachments/bio?";

public final static String RADIOURL = "http://192.168.1.15:8088/fileServer/webapi/Attachments/bio?";

public final static String URL = ImgContants.IMG_UPLOAD + "/file/UpLoadImage?";

public final static String FILEURL = ImgContants.IMG_UPLOAD + "/file/UpLoadFile?";

public final static String VEDIOURL = ImgContants.FILE_UPLOAD + "/file/UpLoadFile?";

public final static String CROPURL = ImgContants.IMG_UPLOAD + "/file/CropImage?";

private static byte[] readAsByteArr(InputStream is) {

ByteArrayOutputStream baos = new ByteArrayOutputStream();

try {

byte[] bytes = new byte[1024];

int length = 0;

while ((length = is.read(bytes)) != -1) {

baos.write(bytes, 0, length);

}

return baos.toByteArray();

} catch (Exception e) {

e.printStackTrace();

} finally {

try {

baos.close();

} catch (IOException e) {

e.printStackTrace();

}

return null;

}

/**

* 上传图片

* @param file

public static String submitImage(File file) throws UnsupportedEncodingException {

String fileName = URLEncoder.encode(file.getName(), "UTF-8");

long fileSize = file.length();

boolean isReSuffix = true;

int height = 0;

int width = 500;

String mark = "t";

String mode = "W";

String url = sign(URL)

+ "&ChannelNo=muying_android"

+ "&FileName="

+ fileName

+ "&FileSize="

+ fileSize

+ "&IsReSuffix="

+ isReSuffix

+ "&Height="

+ height

+ "&Width="

+ width + "&Mark=" + mark + "&Mode=" + mode;

System.out.println("url:" + url);

HttpURLConnection conn = null;

OutputStream outStream = null;

BufferedInputStream bin = null;

try {

bin = new BufferedInputStream(new FileInputStream(file));

conn = (HttpURLConnection) new URL(url)

.openConnection();

conn.setConnectTimeout(15000);

conn.setRequestMethod("POST");

conn.setDoOutput(true);

// conn.setFixedLengthStreamingMode(file.length());

conn.setRequestProperty("Content-Type",

"application/x-www-form-urlencoded");

conn.setRequestProperty("Content-Length", file.length()

+ "");

// conn.setRequestProperty("Range", "bytes="+"");

// 设置 HttpURLConnection的字符编码

conn.setRequestProperty("Accept-Charset", "UTF-8");

outStream = conn.getOutputStream();

byte[] buf = new byte[1024];

int len = 0;

int lenCount = 0;

while ((len = bin.read(buf)) != -1) {

outStream.write(buf, 0, len);//OK

lenCount = lenCount + len;

}

outStream.flush();

int responseCode = conn.getResponseCode();

if (responseCode == 200) {

InputStream inStream = conn.getInputStream();

byte[] data1 = readAsByteArr(inStream);

String json = new String(data1);

inStream.close();

return json;

} else {

InputStream inStream = conn.getInputStream();

byte[] data1 = readAsByteArr(inStream);

String json = new String(data1);

inStream.close();

return json;

}

} catch (Exception e) {

e.printStackTrace();

} finally {

try {

if (outStream != null) {

outStream.close();

}

} catch (IOException e) {

e.printStackTrace();

}

return null;

}

/**

* 上传图片

* @param file

public static String submitWebImage(MultipartFile file) throws UnsupportedEncodingException {

String fileName = URLEncoder.encode(file.getOriginalFilename(), "UTF-8");

long fileSize = file.getSize();

boolean isReSuffix = true;

int height = 0;

int width = 500;

String mark = "t";

String mode = "W";

String url = sign(URL)

+ "&ChannelNo=muying_android"

+ "&FileName="

+ fileName

+ "&FileSize="

+ fileSize

+ "&IsReSuffix="

+ isReSuffix

+ "&Height="

+ height

+ "&Width="

+ width + "&Mark=" + mark + "&Mode=" + mode;

System.out.println("url:" + url);

HttpURLConnection conn = null;

OutputStream outStream = null;

BufferedInputStream bin = null;

try {

bin = new BufferedInputStream(file.getInputStream());

conn = (HttpURLConnection) new URL(url)

.openConnection();

conn.setConnectTimeout(15000);

conn.setRequestMethod("POST");

conn.setDoOutphttp://ut(true);

// conn.setFixedLengthStreamingMode(file.length());

conn.setRequestProperty("Content-Type",

"application/x-www-form-urlencoded");

conn.setRequestProperty("Content-Length", file.getSize()

+ "");

// conn.setRequestProperty("Range", "bytes="+"");

// 设置 HttpURLConnection的字符编码

conn.setRequestProperty("Accept-Charset", "UTF-8");

outStream = conn.getOutputStream();

byte[] buf = new byte[1024];

int len = 0;

int lenCount = 0;

while ((len = bin.read(buf)) != -1) {

outStream.write(buf, 0, len);//OK

lenCount = lenCount + len;

}

outStream.flush();

int responseCode = conn.getResponseCode();

if (responseCode == 200) {

InputStream inStream = conn.getInputStream();

byte[] data1 = readAsByteArr(inStream);

String json = new String(data1);

inStream.close();

return json;

} else {

InputStream inStream = conn.getInputStream();

byte[] data1 = readAsByteArr(inStream);

String json = new String(data1);

inStream.close();

return json;

}

} catch (Exception e) {

e.printStackTrace();

} finally {

try {

if (outStream != null) {

outStream.close();

}

} catch (IOException e) {

e.printStackTrace();

}

return null;

}

/**

* 上传视频

* @param file

public static String submitRadio(MultipartFile file) throws Exception {

String url = signRadio(RADIOURL);

System.out.println("url:" + url);

HttpURLConnection conn = null;

OutputStream outStream = null;

BufferedInputStream bin = null;

try {

bin = new BufferedInputStream(file.getInputStream());

conn = (HttpURLConnection) new URL(url)

.openConnection();

conn.setConnectTimeout(15000);

conn.setRequestMethod("POST");

conn.setDoOutput(true);

conn.setRequestProperty("Content-Type",

"application/x-www-form-urlencoded");

conn.setRequestProperty("Content-Length", file.getSize()

+ "");

conn.setRequestProperty("Accept-Charset", "UTF-8");

outStream = conn.getOutputStream();

byte[] buf = new byte[1024];

int len = 0;

int lenCount = 0;

while ((len = bin.read(buf)) != -1) {

outStream.write(buf, 0, len);//OK

lenCount = lenCount + len;

}

outStream.flush();

int responseCode = conn.getResponseCode();

if (responseCode == 200) {

InputStream inStream = conn.getInputStream();

byte[] data1 = readAsByteArr(inStream);

String json = new String(data1);

inStream.close();

return json;

} else {

InputStream inStream = conn.getInputStream();

byte[] data1 = readAsByteArr(inStream);

String json = new String(data1);

inStream.close();

return json;

}

} catch (Exception e) {

e.printStackTrace();

} finally {

try {

if (outStream != null) {

outStream.close();

}

} catch (IOException e) {

e.printStackTrace();

}

return null;

}

/**

* 上传简历快照

* @param fileName

* @param content

* @return

* @throws UnsupportedEncodingException

public static String submitFile(String fileName, String content) throws UnsupportedEncodingException {

//content = URLEncoder.encode(content, "UTF-8");

fileName = URLEncoder.encode(fileName, "UTF-8");

byte[] contentBytes = content.getBytes();

long fileSize = contentBytes.length;

boolean isReSuffix = true;

int height = 0;

int width = 500;

String mark = "t";

String mode = "W";

String url = sign(FILEURL)

+ "&ChannelNo=muying_android"

+ "&FileName="

+ fileName

+ "&FileSize="

+ fileSize

+ "&IsReSuffix="

+ isReSuffix

+ "&Height="

+ height

+ "&Width="

+ width + "&Mark=" + mark + "&Mode=" + mode;

System.out.println("url:" + url);

HttpURLConnection conn = null;

OutputStream outStream = null;

BufferedInputStream bin = null;

try {

conn = (HttpURLConnection) new URL(url)

.openConnection();

conn.setConnectTimeout(15000);

conn.setRequestMethod("POST");

conn.setDoOutput(true);

// conn.setFixedLengthStreamingMode(file.length());

conn.setRequestProperty("Content-Type",

"application/x-www-form-urlencoded");

conn.setRequestProperty("Content-Length", content.length()

+ "");

// conn.setRequestProperty("Range", "bytes="+"");

// 设置 HttpURLConnection的字符编码

conn.setRequestProperty("Accept-Charset", "UTF-8");

outStream = conn.getOutputStream();

outStream.write(contentBytes, 0, contentBytes.length);//OK

outStream.flush();

int responseCode = conn.getResponseCode();

if (responseCode == 200) {

InputStream inStream = conn.getInputStream();

byte[] data1 = readAsByteArr(inStream);

String json = new String(data1);

inStream.close();

return json;

} else {

InputStream inStream = conn.getInputStream();

byte[] data1 = readAsByteArr(inStream);

String json = new String(data1);

inStream.close();

return json;

}

} catch (Exception e) {

e.printStackTrace();

} finally {

try {

if (outStream != null) {

outStream.close();

}

} catch (IOException e) {

e.printStackTrace();

}

return null;

}

/**

* 上传附件

* @return json 字符串

* @throws UnsupportedEncodingException

public static String submitFile(MultipartFile file) throws UnsupportedEncodingException {

String fileName = URLEncoder.encode(file.getOriginalFilename(), "UTF-8");

long fileSize = file.getSize();

boolean isReSuffix = true;

int height = 0;

int width = 500;

String mark = "t";

String mode = "W";

String url = sign(FILEURL)

+ "&ChannelNo=muying_android"

+ "&FileName="

+ fileName

+ "&FileSize="

+ fileSize

+ "&IsReSuffix="

+ isReSuffix

+ "&Height="

+ height

+ "&Width="

+ width + "&Mark=" + mark + "&Mode=" + mode;

System.out.println("url:" + url);

HttpURLConnection conn = null;

OutputStream outStream = null;

BufferedInputStream bin = null;

try {

bin = new BufferedInputStream(file.getInputStream());

conn = (HttpURLConnection) new URL(url)

.openConnection();

conn.setConnectTimeout(15000);

conn.setRequestMethod("POST");

conn.setDoOutput(true);

// conn.setFixedLengthStreamingMode(file.length());

conn.setRequestProperty("Content-Type",

"application/x-www-form-urlencoded");

conn.setRequestProperty("Content-Length", file.getSize()

+ "");

// conn.setRequestProperty("Range", "bytes="+"");

// 设置 HttpURLConnection的字符编码

conn.setRequestProperty("Accept-Charset", "UTF-8");

outStream = conn.getOutputStream();

byte[] buf = new byte[1024];

int len = 0;

int lenCount = 0;

while ((len = bin.read(buf)) != -1) {

outStream.write(buf, 0, len);//OK

lenCount = lenCount + len;

}

int responseCode = conn.getResponseCode();

if (responseCode == 200) {

InputStream inStream = conn.getInputStream();

byte[] data1 = readAsByteArr(inStream);

String json = new String(data1);

inStream.close();

return json;

} else {

InputStream inStream = conn.getInputStream();

byte[] data1 = readAhttp://sByteArr(inStream);

String json = new String(data1);

inStream.close();

return json;

}

} catch (Exception e) {

e.printStackTrace();

} finally {

try {

if (outStream != null) {

outStream.close();

}

} catch (IOException e) {

e.printStackTrace();

}

return null;

}

private static String sign(String baseurl) throws UnsupportedEncodingException {

long currebttime = System.currentTimeMillis();

long timeStamp = currebttime / 1000;

String data = "ActionName=UpLoadImage" + "&SecretKey=4b19f08dbf0adb82ce9cc7c207ec1dc9"

+ "&TimeStamp=" + timeStamp;

String signature = hmac_sha1("4b19f08dbf0adb82ce9cc7c207ec1dc9",

URLEncoder.encode(data, "UTF-8"));

signature = signature.replace("%3D", "%3d");

signature = signature.replace("%3A", "%3a");

signature = signature.replace("%2F", "%2f");

return baseurl + data + "&Signature=" + signature;

}

private static String signRadio(String url) throws Exception {

long currebttime = System.currentTimeMillis();

String data = "secretKey=f1b79c865c424be46183a2f0a49a0f15"

+ "&timeStamp=" + currebttime;

System.out.println("url:" + url + data);

System.out.println("url = " + URLEncoder.encode(url + data, "utf-8"));

String signature = HmacSha1Util.getSignature(URLEncoder.encode(url + data, "utf-8"), "f1b79c865c424be46183a2f0a49a0f15");

return url + data + "&signature=" + signature;

}

private static String hmac_sha1(String key, String datas) {

String reString = "";

try {

datas = datas.replace("%3A", "%3a");

datas = datas.replace("%2F", "%2f");

datas = datas.replace("%3D", "%3d");

byte[] data = key.getBytes("UTF-8");

// 根据给定的字节数组构造一个密钥,第二参数指定一个密钥算法的名称

SecretKey secretKey = new SecretKeySpec(data, "HmacSHA1");

// 生成一个指定 Mac 算法的 Mac 对象

Mac mac = Mac.getInstance("HmacSHA1");

// 用给定密钥初始化 Mac 对象

mac.init(secretKey);

byte[] text = datas.getBytes("UTF-8");

// 完成 Mac 操作

byte[] text1 = mac.doFinal(text);

reString = new BASE64Encoder().encodeBuffer(text1);

reString = URLEncoder.encode(reString, "UTF-8");

reString = reString.replace("%0A", "");

reString = reString.replace("%0D", "");

} catch (Exception e) {

e.printStackTrace();

}

return reString;

}

/**

* 上传裁剪图片

* zxiao 2016/09/01

* @param fileID

public static String submitCutedWebImage(MultipartFile file,String fileID,String x,String y,String w,String h) throws UnsupportedEncodingException {

String FileId=fileID;

String[] CropWidths=new String[]{"50"};//裁剪宽度

//List list=new List();

//List list = new ArrayList(5);

ArrayList listCropWidths = new ArrayList();

listCropWidths.add("400");

// String[] CropHeights=new String[]{"50"};//裁剪高度

ArrayList listCropHeights = new ArrayList();

listCropHeights.add("300");

int CropX=Integer.parseInt(x);//裁剪x坐标

int CropY=Integer.parseInt(y);//裁剪y坐标

// String[] CropFixs=new String[]{"l"};//裁剪图片的标示集合

ArrayList listCropFixs = new ArrayList();

listCropFixs.add("l");

String SourceSuffix="jpg";//底图后缀

String SourceFix="";//底图标示

/* boolean isReSuffix = true;

int height = 1000;

int width = 750;

String mark = "t";

String mode = "W";*/

String url = sign(CROPURL) + "FileId="

+ fileID

+ "&CropWidths="

+ listCropWidths

+ "&CropHeights="

+ listCropHeights

+ "&CropX="

+ CropX

+ "&CropY="

+ CropY + "&CropFixs=" + listCropFixs + "&SourceSuffix=" + SourceSuffix+ "&SourceFix=" + SourceFix;

System.out.println("url:" + url);

HttpURLConnection conn = null;

OutputStream outStream = null;

BufferedInputStream bin = null;

try {

bin = new BufferedInputStream(file.getInputStream());

conn = (HttpURLConnection) new URL(url)

.openConnection();

conn.setConnectTimeout(15000);

conn.setRequestMethod("POST");

conn.setDoOutput(true);

// conn.setFixedLengthStreamingMode(file.length());

conn.setRequestProperty("Content-Type",

"application/x-www-form-urlencoded");

conn.setRequestProperty("Content-Length", file.getSize()

+ "");

// conn.setRequestProperty("Range", "bytes="+"");

// 设置 HttpURLConnection的字符编码

conn.setRequestProperty("Accept-Charset", "UTF-8");

outStream = conn.getOutputStream();

byte[] buf = new byte[1024];

int len = 0;

int lenCount = 0;

while ((len = bin.read(buf)) != -1) {

outStream.write(buf, 0, len);//OK

lenCount = lenCount + len;

}

int responseCode = conn.getResponseCode();

if (responseCode == 200) {

InputStream inStream = conn.getInputStream();

byte[] data1 = readAsByteArr(inStream);

String json = new String(data1);

inStream.close();

return json;

} else {

InputStream inStream = conn.getInputStream();

byte[] data1 = readAsByteArr(inStream);

String json = new String(data1);

inStream.close();

return json;

}

} catch (Exception e) {

e.printStackTrace();

} finally {

try {

if (outStream != null) {

outStream.close();

}

} catch (IOException e) {

e.printStackTrace();

}

return null;

}

/**上传裁剪后图片需在本地保存副本

*zxiao 2016/09/01

* @param ，

* @param x

* @param y

* @param w

* @param h

* @return

* @throws IOException

public static String submitCropImage(MultipartFile file,Integer x,Integer y,Integer w,Integer h) throws IOException {

String folder=System.getProperty("java.io.tmpdir");

File tempDir =new File(folder);

//如果文件夹不存在则创建

if (!tempDir .exists() && !tempDir .isDirectory())

{

// System.out.println("//不存在");

tempDir .mkdir();

}

//压缩后临时文件

String Srcpath=folder+"scaleTemp.jpg";

//获取文件的后缀

/*File uploadFile = new File(Srcpath);

InputStream inputStream = file.getInputStream();

FileInputStream fs= (FileInputStream) inputStream;

String srcImg = URLEncoder.encode(file.getOriginalFilename(), "UTF-8");

String suffix=srcImg.substring(srcImg.lastIndexOf(".")+1);*/

//裁剪图片

cutImgUtils o = new cutImgUtils(x,y,w,h);

o.setSrcpath(Srcpath);

o.setSubpath(folder+"uptemp.jpg");

File tempFile = o.cut("jpg");

String s = submitImage(tempFile);

return s;

}

/**

* 获取上传图片的宽

* zxiao 2016/09/09

* @param file

* @return

public static int getImgWidth(MultipartFile file) throws IOException {

InputStream is = null;

BufferedImage src = null;

int ret = -1;

try {

is = file.getInputStream();

src = javax.imageio.ImageIO.read(is);

ret = src.getWidth(null); // 得到源图宽

is.close();

} catch (Exception e) {

e.printStackTrace();

}

return ret;

}

/**

* 获取上传图片的高

* zxiao 2016/09/09

* @param file

* @return

public static int getImgHeight(MultipartFile file) {

InputStream is = null;

BufferedImage src = null;

int ret = -1;

try {

is = file.getInputStream();

src = javax.imageio.ImageIO.read(is);

ret = src.getHeight(null); // 得到源图高

is.close();

} catch (Exception e) {

e.printStackTrace();

}

return ret;

}

/**

* 缩放图像（按高度和宽度缩放）

* @param file 文件对象

* @param result 缩放后的图像地址

* @param height 缩放后的高度

* @param width 缩放后的宽度

* @param bb 比例不对时是否需要补白：true为补白; false为不补白;

public static void scale(MultipartFile file, String result, int height, int width, boolean bb) {

try {

double ratio = 0.0; // 缩放比例

/*CommonsMultipartFile cf= (CommonsMultipartFile)file;

DiskFileItem fi = (DiskFileItem)cf.getFileItem();

File f = fi.getStoreLocation();*/

// File f = new File(srcImageFile);

InputStream inputStream = file.getInputStream();

BufferedImage bi = ImageIO.read(inputStream);

Image itemp = bi.getScaledInstance(width, height, bi.SCALE_SMOOTH);

// 计算比例

if ((bi.getHeight() > height) || (bi.getWidth() > width)) {

if (bi.getHeight() > bi.getWidth()) {

ratio = (new Integer(height)).doubleValue()

/ bi.getHeight();

} else {

ratio = (new Integer(width)).doubleValue() / bi.getWidth();

}

AffineTransformOp op = new AffineTransformOp(AffineTransform

.getScaleInstance(ratio, ratio), null);

itemp = op.filter(bi, null);

}

if (bb) {//补白

BufferedImage image = new BufferedImage(width, height,

BufferedImage.TYPE_INT_RGB);

Graphics2D g = image.createGraphics();

g.setColor(Color.white);

g.fillRect(0, 0, width, height);

if (width == itemp.getWidth(null))

g.drawImage(itemp, 0, (height - itemp.getHeight(null)) / 2,

itemp.getWidth(null), itemp.getHeight(null),

Color.white, null);

else

g.drawImage(itemp, (width - itemp.getWidth(null)) / 2, 0,

itemp.getWidth(null), itemp.getHeight(null),

Color.white, null);

g.dispose();

itemp = image;

}

ImageIO.write((BufferedImage) itemp, "jpg", new File(result));

} catch (IOException e) {

e.printStackTrace();

}

public static void main(String[] args) {

try {

/* File file = new File("E:\\bole\\doc\\服务接口文档\\伯乐服务接口说明v1.0.docx");

System.out.println("file = " + file);

String json = submitFile(file);

System.out.println("json = " + json);*/

} catch (Exception e) {

e.printStackTrace();

}

图片裁剪工具类

package com.shengya.service.utils;

import javax.imageio.ImageIO;

import javax.imageio.ImageReadParam;

import javax.imageio.ImageReader;

import javax.imageio.stream.ImageInputStream;

import java.awt.*;

import java.awt.image.BufferedImage;

import java.io.File;

import java.io.FileInputStream;

import java.io.IOException;

import java.util.Iterator;

/**

* Created by Administrator on 2016/9/1.

public class cutImgUtils {

// ===源图片路径名称如：c:\1.jpg

private String srcpath;

// ===剪切图片存放路径名称。如：c:\2.jpg

private String subpath;

public void setSrcpath(String srcpath) {

this.srcpath = srcpath;

}

public void setSubpath(String subpath) {

this.subpath = subpath;

}

// ===剪切点x坐标

private int x;

private int y;

// ===剪切点宽度

private int width;

private int height;

public cutImgUtils() {

}

public cutImgUtils(int x, int y, int width, int height) {

if(x<0){

x=0;

}else{

this.x = x;

}

if(y<0){

y=0;

}else{

this.y = y;

}

this.width = width;

this.height = height;

}

/**

* 对图片裁剪，并把裁剪完蛋新图片保存。

public File cut() throws IOException {

FileInputStream is = null;

ImageInputStream iis = null;

try {

// 读取图片文件

is = new FileInputStream(srcpath);

/**

* 返回包含所有当前已注册 ImageReader 的 Iterator，这些 ImageReader

* 声称能够解码指定格式。参数：formatName - 包含非正式格式名称 .

* (例如 "jpeg" 或 "tiff")等。

Iterator it = ImageIO

.getImageReadersByFormatName("jpg");

ImageReader reader = it.next();

// 获取图片流

iis = ImageIO.createImageInputStream(is);

/**

* iis:读取源。true:只向前搜索

* .将它标记为 ‘只向前搜索'。

* 此设置意味着包含在输入源中的图像将只按顺序读取，可能允许 reader

* 避免缓存包含与以前已经读取的图像关联的数据的那些输入部分。

reader.setInput(iis, true);

/**

* 描述如何对流进行解码的类

* .用于指定如何在输入时从 Java Image I/O

* 框架的上下文中的流转换一幅图像或一组图像。用于特定图像格式的插件

* 将从其 ImageReader 实现的 getDefaultReadParam 方法中返回

* ImageReadParam 的实例。

ImageReadParam param = reader.getDefaultReadParam();

/**

* 图片裁剪区域。Rectangle 指定了坐标空间中的一个区域，通过 Rectangle 对象

* 的左上顶点的坐标(x，y)、宽度和高度可以定义这个区域。

Rectangle rect = new Rectangle(x, y, width, height);

// 提供一个 BufferedImage，将其用作解码像素数据的目标。

param.setSourceRegion(rect);

/**

* 使用所提供的 ImageReadParam 读取通过索引 imageIndex 指定的对象，并将

* 它作为一个完整的 BufferedImage 返回。

BufferedImage bi = reader.read(0, param);

// 保存新图片

ImageIO.write(bi, "jpg", new File(subpath));

File file = new File("subpath");

return file;

} finally {

if (is != null)

is.close();

if (iis != null)

iis.close();

}

public File cut(String suffix) throws IOException {

FileInputStream is = null;

ImageInputStream iis = null;

try {

// 读取图片文件

is = new FileInputStream(srcpath);

// is = inputStream;

/**

* 返回包含所有当前已注册 ImageReader 的 Iterator，这些 ImageReader

* 声称能够解码指定格式。参数：formatName - 包含非正式格式名称 .

* (例如 "jpeg" 或 "tiff")等。

* Iterator it = ImageIO.getImageReadersByFormatName("jpg");

String suffixName=null;

if(suffix.equals("gif")){

suffixName="gif";

}else if(suffix.equals("png")){

suffixName="png";

} else{

suffixName="jpg";

}

Iterator it = ImageIO

.getImageReadersByFormatName(suffixName);

ImageReader reader = it.next();

// 获取图片流

iis = ImageIO.createImageInputStream(is);

/**

* iis:读取源。true:只向前搜索

* .将它标记为 ‘只向前搜索'。

* 此设置意味着包含在输入源中的图像将只按顺序读取，可能允许 reader

* 避免缓存包含与以前已经读取的图像关联的数据的那些输入部分。

reader.setInput(iis, true);

/**

* 描述如何对流进行解码的类

* .用于指定如何在输入时从 Java Image I/O

* 框架的上下文中的流转换一幅图像或一组图像。用于特定图像格式的插件

* 将从其 ImageReader 实现的 getDefaultReadParam 方法中返回

* ImageReadParam 的实例。

ImageReadParam param = reader.getDefaultReadParam();

/**

* 图片裁剪区域。Rectangle 指定了坐标空间中的一个区域，通过 Rectangle 对象

* 的左上顶点的坐标(x，y)、宽度和高度可以定义这个区域。

Rectangle rect = new Rectangle(x, y, width, height);

// 提供一个 BufferedImage，将其用作解码像素数据的目标。

param.setSourceRegion(rect);

/**

* 使用所提供的 ImageReadParam 读取通过索引 imageIndex 指定的对象，并将

* 它作为一个完整的 BufferedImage 返回。

BufferedImage bi = reader.read(0, param);

// 保存新图片

ImageIO.write(bi, "jpg", new File(subpath));

File file = new File(subpath);

return file;

} finally {

if (is != null)

is.close();

if (iis != null)

iis.close();

}

遇到的问题总结：

-裁剪图片发生偏移现象

解决办法：使用压缩后的图片等比例收集裁切坐标信息

-MultipartFile 和 File之间相互转化

第一种方法：

MultipartFile file = xxx;

CommonsMultipartFile cf= (CommonsMultipartFile)file;

DiskFileItem fi = (DiskFileItem)cf.getFileItem();

File f = fi.getStoreLocation();

会在项目的根目录的临时文件夹下生成一个文件；

第二种方法：

transferTo(File dest)；

会在项目中生成一个新文件；

第三种方法：

File f = (File) xxx 强转即可。前提是要配置multipartResolver，要不然会报类型转换失败的异常。

没试过；

第四种方法：

Workbook wb = Workbook.getWorkbook(xxx .getInputStream());

转换为输入流，直接读取；

第五种方法：

byte[] buffer = myfile.getBytes();

先转换为字节数组，没试过；

第六种方法：

直接转成输入流

MultipartFile file=xxx;

is = file.getInputStream();

src = javax.imageio.ImageIO.read(is);

ret = src.getWidth(null); // 得到源图宽

参考资料：

jcop api：http://code.ciaoca.com/jquery/jcrop/.

Flask接口签名sign原理与实例代码浅析

209 2023-07-06

JavaWeb实现裁剪图片上传完整代码

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