java等比例壓縮

① java中怎麼等比例壓縮後,從中間取出圖片.最好例子!謝謝大家

期待高手。

② java如何實現把一個大圖片壓縮到指定大小的圖片且長寬比不變

java要實現把一個大圖片壓縮到指定大小的圖片且長寬比不變可以嘗試以下操作：

③ java 壓縮比

ZipOutputStream

裡面有
setMethodpublic void setMethod(int method)設置用於後續條目的默認壓縮方法。只要沒有為單個 ZIP 文件條目指定壓縮方法，並且其初始設置為 DEFLATED 時，就使用此默認值。

參數：method - 默認壓縮方法
拋出：IllegalArgumentException - 如果指定的壓縮方法無效
setLevelpublic void setLevel(int level)為後續的 DEFLATED 條目設置壓縮級別。默認設置是 DEFAULT_COMPRESSION。

參數：level - 壓縮級別 (0-9)
拋出：IllegalArgumentException - 如果壓縮級別無效

④ java上傳圖片 生成縮略圖，如果上傳的圖片尺寸比較小就壓縮處理

//將圖按比例縮小。
public static BufferedImage resize(BufferedImage source, int targetW, int targetH) {
// targetW，targetH分別表示目標長和寬
int type = source.getType();
BufferedImage target = null;
double sx = (double) targetW / source.getWidth();
double sy = (double) targetH / source.getHeight();
//這里想實現在targetW，targetH范圍內實現等比縮放。如果不需要等比縮放
//則將下面的if else語句注釋即可
if(sx>sy)
{
sx = sy;
targetW = (int)(sx * source.getWidth());
}else{
sy = sx;
targetH = (int)(sy * source.getHeight());
}
if (type == BufferedImage.TYPE_CUSTOM) { //handmade
ColorModel cm = source.getColorModel();
WritableRaster raster = cm.(targetW, targetH);
boolean alphaPremultiplied = cm.isAlphaPremultiplied();
target = new BufferedImage(cm, raster, alphaPremultiplied, null);
} else
target = new BufferedImage(targetW, targetH, type);
Graphics2D g = target.createGraphics();
//smoother than exlax:
g.setRenderingHint(RenderingHints.KEY_RENDERING, RenderingHints.VALUE_RENDER_QUALITY );
g.drawRenderedImage(source, AffineTransform.getScaleInstance(sx, sy));
g.dispose();
return target;
}

public static void saveImageAsJpg (String fromFileStr,String saveToFileStr,int width,int hight)
throws Exception {
BufferedImage srcImage;
// String ex = fromFileStr.substring(fromFileStr.indexOf("."),fromFileStr.length());
String imgType = "JPEG";
if (fromFileStr.toLowerCase().endsWith(".png")) {
imgType = "PNG";
}
// System.out.println(ex);
File saveFile=new File(saveToFileStr);
File fromFile=new File(fromFileStr);
srcImage = ImageIO.read(fromFile);
if(width > 0 || hight > 0)
{
srcImage = resize(srcImage, width, hight);
}
ImageIO.write(srcImage, imgType, saveFile);

}

public static void main (String argv[]) {
try{
//參數1(from),參數2(to),參數3(寬),參數4(高)
saveImageAsJpg("C:\\Documents and Settings\\xugang\\桌面\\tmr-06.jpg",
"C:\\Documents and Settings\\xugang\\桌面\\2.jpg",
120,120);
} catch(Exception e){
e.printStackTrace();
}

}

⑤ java將圖片按比例縮小

Image srcImg = ImageIO.read(new FileInputStream(fnSrc) );//取源圖
int width = 600; //假設要縮小到600點像素
int height = srcImg.getHeight(null)*600/srcImg.getWidth(null);//按比例，將高度縮減

System.out.println("Width: "+srcImg.getWidth(null));// 這幾行是調試用
System.out.println("Height: "+srcImg.getHeight(null));
System.out.println("Width2: "+width);
System.out.println("Height2: "+height);

Image smallImg =srcImg.getScaledInstance(width, height, Image.SCALE_SMOOTH);//縮小

⑥ 您好！請問用java怎麼將截取png的圖片中間一部分，以及如何壓縮一個png圖片

• getSubimage方法是進行圖片裁剪。

舉例：
public static void main(String[] args) {
try {
//從特定文件載入
BufferedImage bi = ImageIO.read(new File("c:\test.png"));
bi.getSubimage(0, 0, 10, 10);//前兩個值是坐標位置X、Y，後兩個是長和寬
} catch (IOException e) {
e.printStackTrace();
}
}

• 以下是進行的圖片壓縮，涉及到多個工具類。
  

/**
* 圖片工具類
* 壓縮圖片大小
* @author Cyw
* @version 1.0
*/
public class ZIPImage {

private File file = null;

private String outPutFilePath;

private String inPutFilePath;

private String inPutFileName;

private boolean autoBuildFileName;

private String outPutFileName;

private int outPutFileWidth = 100; // 默認輸出圖片寬

private int outPutFileHeight = 100; // 默認輸出圖片高

private static boolean isScaleZoom = true; // 是否按比例縮放

public ZIPImage() {
outPutFilePath = "";
inPutFilePath = "";
inPutFileName = "";
autoBuildFileName = true;
outPutFileName = "";
}

/**
*
* @param ipfp
* 源文件夾路徑
* @param ipfn
* 源文件名
* @param opfp
* 目標文件路徑
* @param opfn
* 目標文件名
*/
public ZIPImage(String ipfp, String ipfn, String opfp, String opfn) {
outPutFilePath = opfp;
inPutFilePath = ipfp;
inPutFileName = ipfn;
autoBuildFileName = true;
outPutFileName = opfn;
}

/**
*
* @param ipfp
* 源文件夾路徑
* @param ipfn
* 源文件名
* @param opfp
* 目標文件路徑
* @param opfn
* 目標文件名
* @param aBFN
* 是否自動生成目標文件名
*/
public ZIPImage(String ipfp, String ipfn, String opfp, String opfn,
boolean aBFN) {
outPutFilePath = opfp;
inPutFilePath = ipfp;
inPutFileName = ipfn;
autoBuildFileName = aBFN;
outPutFileName = opfn;
}

public boolean isAutoBuildFileName() {
return autoBuildFileName;
}

public void setAutoBuildFileName(boolean autoBuildFileName) {
this.autoBuildFileName = autoBuildFileName;
}

public String getInPutFilePath() {
return inPutFilePath;
}

public void setInPutFilePath(String inPutFilePath) {
this.inPutFilePath = inPutFilePath;
}

public String getOutPutFileName() {
return outPutFileName;
}

public void setOutPutFileName(String outPutFileName) {
this.outPutFileName = outPutFileName;
}

public String getOutPutFilePath() {
return outPutFilePath;
}

public void setOutPutFilePath(String outPutFilePath) {
this.outPutFilePath = outPutFilePath;
}

public int getOutPutFileHeight() {
return outPutFileHeight;
}

public void setOutPutFileHeight(int outPutFileHeight) {
this.outPutFileHeight = outPutFileHeight;
}

public int getOutPutFileWidth() {
return outPutFileWidth;
}

public void setOutPutFileWidth(int outPutFileWidth) {
this.outPutFileWidth = outPutFileWidth;
}

public boolean isScaleZoom() {
return isScaleZoom;
}

public void setScaleZoom(boolean isScaleZoom) {
this.isScaleZoom = isScaleZoom;
}

public String getInPutFileName() {
return inPutFileName;
}

public void setInPutFileName(String inPutFileName) {
this.inPutFileName = inPutFileName;
}

/**
* 壓縮圖片大小
*
* @return boolean
*/
public boolean compressImage() {
boolean flag = false;

try {
if (inPutFilePath.trim().equals("")) {
throw new NullPointerException("源文件夾路徑不存在。");
}
if (inPutFileName.trim().equals("")) {
throw new NullPointerException("圖片文件路徑不存在。");
}
if (outPutFilePath.trim().equals("")) {
throw new NullPointerException("目標文件夾路徑地址為空。");
} else {
if (!ZIPImage.mddir(outPutFilePath)) {
throw new FileNotFoundException(outPutFilePath
+ " 文件夾創建失敗！");
}
}

if (this.autoBuildFileName) { // 自動生成文件名
String tempFile[] = getFileNameAndExtName(inPutFileName);
outPutFileName = tempFile[0] + "_cyw." + tempFile[1];
compressPic();
} else {
if (outPutFileName.trim().equals("")) {
throw new NullPointerException("目標文件名為空。");
}
compressPic();
}

} catch (Exception e) {
flag = false;
e.printStackTrace();
return flag;
}

return flag;
}

// 圖片處理
private void compressPic() throws Exception {
try {
// 獲得源文件
file = new File(inPutFilePath + inPutFileName);
if (!file.exists()) {
throw new FileNotFoundException(inPutFilePath + inPutFileName
+ " 文件不存在！");
}
Image img = ImageIO.read(file);
// 判斷圖片格式是否正確
if (img.getWidth(null) == -1) {
throw new Exception("文件不可讀！");
} else {
int newWidth;
int newHeight;
// 判斷是否是等比縮放
if (ZIPImage.isScaleZoom == true) {
// 為等比縮放計算輸出的圖片寬度及高度
double rate1 = ((double) img.getWidth(null))
/ (double) outPutFileWidth + 0.1;
double rate2 = ((double) img.getHeight(null))
/ (double) outPutFileHeight + 0.1;

// 根據縮放比率大的進行縮放控制
double rate = rate1 > rate2 ? rate1 : rate2;

newWidth = (int) (((double) img.getWidth(null)) / rate);
newHeight = (int) (((double) img.getHeight(null)) / rate);

} else {
newWidth = outPutFileWidth; // 輸出的圖片寬度
newHeight = outPutFileHeight; // 輸出的圖片高度
}

BufferedImage tag = new BufferedImage((int) newWidth,
(int) newHeight, BufferedImage.TYPE_INT_RGB);

/*
* Image.SCALE_SMOOTH 的縮略演算法 生成縮略圖片的平滑度的 優先順序比速度高 生成的圖片質量比較好 但速度慢
*/
tag.getGraphics().drawImage(
img.getScaledInstance(newWidth, newHeight,
Image.SCALE_SMOOTH), 0, 0, null);

FileOutputStream out = new FileOutputStream(outPutFilePath
+ outPutFileName);

JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(out);
encoder.encode(tag);
out.close();

}
} catch (IOException ex) {
ex.printStackTrace();
}
}

/**
* 創建文件夾目錄
*
* @param filePath
* @return
* @throws Exception
*/
@SuppressWarnings("unused")
private static boolean mddir(String filePath) throws Exception {
boolean flag = false;
File f = new File(filePath);
if (!f.exists()) {
flag = f.mkdirs();
} else {
flag = true;
}
return flag;
}

/**
* 獲得文件名和擴展名
*
* @param fullFileName
* @return
* @throws Exception
*/
private String[] getFileNameAndExtName(String fullFileName)
throws Exception {
String[] fileNames = new String[2];
if (fullFileName.indexOf(".") == -1) {
throw new Exception("源文件名不正確！");
} else {
fileNames[0] = fullFileName.substring(0, fullFileName
.lastIndexOf("."));
fileNames[1] = fullFileName
.substring(fullFileName.lastIndexOf(".") + 1);
}
return fileNames;
}

public Image getSourceImage() throws IOException{
//獲得源文件
file = new File(inPutFilePath + inPutFileName);
if (!file.exists()) {
throw new FileNotFoundException(inPutFilePath + inPutFileName
+ " 文件不存在！");
}
Image img = ImageIO.read(file);
return img;
}

/*
* 獲得圖片大小
* @path ：圖片路徑
*/
public long getPicSize(String path) {
File file = new File(path);
return file.length();
}

}

//下面是測試程序

package com.sun.util.cyw;

import java.awt.Image;
import java.io.IOException;

public class ImageTest {
public static void main(String[] args) throws IOException {
ZIPImage zip=new ZIPImage("d:\","1.jpg","d:\test\","處理後的圖片.jpg",false);
zip.setOutPutFileWidth(1000);
zip.setOutPutFileHeight(1000);

Image image=zip.getSourceImage();
long size=zip.getPicSize("d:\1.jpg");
System.out.println("處理前的圖片大小 width:"+image.getWidth(null));
System.out.println("處理前的圖片大小 height:"+image.getHeight(null));
System.out.println("處理前的圖片容量:"+ size +" bit");

zip.compressImage();
}
}

⑦ 求一個Java無損壓縮圖片的示例，把原圖片復制到指定目錄，按原圖比例改變尺寸，不影響圖片質量。

圖片壓縮就是講圖片的內存變小 對象數坑定有印象 你將壓縮率改小一點 調整一下壓縮率 到自己滿意為止

⑧ java ssh實現微信端操作 有圖片上傳的地方 怎麼能在上傳到伺服器之前進行等比例壓縮

public class struts2UploadAction extends ActionSupport {

private File uploadFile;// 得到上傳的文件

private String uploadFileContentType;// 得到文件的類型

private String uploadFileFileName;// 得到文件的名稱

public String load() throws IOException {

String RealPath = ServletActionContext.getServletContext().getRealPath("/piction");
File file = new File(RealPath);
if(!file.exists()){
file.mkdirs();
}
FileUtils.File(uploadFile, new File(file,uploadFileFileName));
String path=RealPath+"/"+uploadFileFileName;
ServletActionContext.getRequest().setAttribute("realpath",path);
return "success";
}

public File getUploadFile() {
return uploadFile;
}

public void setUploadFile(File uploadFile) {
this.uploadFile = uploadFile;
}

public String getUploadFileContentType() {
return uploadFileContentType;
}

public void setUploadFileContentType(String uploadFileContentType) {
this.uploadFileContentType = uploadFileContentType;
}

public String getUploadFileFileName() {
return uploadFileFileName;
}

public void setUploadFileFileName(String uploadFileFileName) {
this.uploadFileFileName = uploadFileFileName;
}
}

⑨ java壓縮png圖片

您轉換的是圖片的後綴名吧？您這樣的方式已經把圖片的信息刪除了！
http://sjbbs.zol.com.cn/1/313_9068.html您去下載一個java圖片壓縮器吧
或者直接在Java下編輯代碼來實習轉換
package com.sun.util.cyw;

import java.awt.Image;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;

import javax.imageio.ImageIO;

import com.sun.image.codec.jpeg.JPEGCodec;
import com.sun.image.codec.jpeg.JPEGImageEncoder;

/**
* 圖片工具類
* 壓縮圖片大小
* @author Cyw
* @version 1.0
*/
public class ZIPImage {

private File file = null;

private String outPutFilePath;

private String inPutFilePath;

private String inPutFileName;

private boolean autoBuildFileName;

private String outPutFileName;

private int outPutFileWidth = 100; // 默認輸出圖片寬

private int outPutFileHeight = 100; // 默認輸出圖片高

private static boolean isScaleZoom = true; // 是否按比例縮放

public ZIPImage() {
outPutFilePath = "";
inPutFilePath = "";
inPutFileName = "";
autoBuildFileName = true;
outPutFileName = "";
}

/**
*
* @param ipfp
* 源文件夾路徑
* @param ipfn
* 源文件名
* @param opfp
* 目標文件路徑
* @param opfn
* 目標文件名
*/
public ZIPImage(String ipfp, String ipfn, String opfp, String opfn) {
outPutFilePath = opfp;
inPutFilePath = ipfp;
inPutFileName = ipfn;
autoBuildFileName = true;
outPutFileName = opfn;
}

/**
*
* @param ipfp
* 源文件夾路徑
* @param ipfn
* 源文件名
* @param opfp
* 目標文件路徑
* @param opfn
* 目標文件名
* @param aBFN
* 是否自動生成目標文件名
*/
public ZIPImage(String ipfp, String ipfn, String opfp, String opfn,
boolean aBFN) {
outPutFilePath = opfp;
inPutFilePath = ipfp;
inPutFileName = ipfn;
autoBuildFileName = aBFN;
outPutFileName = opfn;
}

public boolean isAutoBuildFileName() {
return autoBuildFileName;
}

public void setAutoBuildFileName(boolean autoBuildFileName) {
this.autoBuildFileName = autoBuildFileName;
}

public String getInPutFilePath() {
return inPutFilePath;
}

public void setInPutFilePath(String inPutFilePath) {
this.inPutFilePath = inPutFilePath;
}

public String getOutPutFileName() {
return outPutFileName;
}

public void setOutPutFileName(String outPutFileName) {
this.outPutFileName = outPutFileName;
}

public String getOutPutFilePath() {
return outPutFilePath;
}

public void setOutPutFilePath(String outPutFilePath) {
this.outPutFilePath = outPutFilePath;
}

public int getOutPutFileHeight() {
return outPutFileHeight;
}

public void setOutPutFileHeight(int outPutFileHeight) {
this.outPutFileHeight = outPutFileHeight;
}

public int getOutPutFileWidth() {
return outPutFileWidth;
}

public void setOutPutFileWidth(int outPutFileWidth) {
this.outPutFileWidth = outPutFileWidth;
}

public boolean isScaleZoom() {
return isScaleZoom;
}

public void setScaleZoom(boolean isScaleZoom) {
this.isScaleZoom = isScaleZoom;
}

public String getInPutFileName() {
return inPutFileName;
}

public void setInPutFileName(String inPutFileName) {
this.inPutFileName = inPutFileName;
}

/**
* 壓縮圖片大小
*
* @return boolean
*/
public boolean compressImage() {
boolean flag = false;

try {
if (inPutFilePath.trim().equals("")) {
throw new NullPointerException("源文件夾路徑不存在。");
}
if (inPutFileName.trim().equals("")) {
throw new NullPointerException("圖片文件路徑不存在。");
}
if (outPutFilePath.trim().equals("")) {
throw new NullPointerException("目標文件夾路徑地址為空。");
} else {
if (!ZIPImage.mddir(outPutFilePath)) {
throw new FileNotFoundException(outPutFilePath
+ " 文件夾創建失敗！");
}
}

if (this.autoBuildFileName) { // 自動生成文件名
String tempFile[] = getFileNameAndExtName(inPutFileName);
outPutFileName = tempFile[0] + "_cyw." + tempFile[1];
compressPic();
} else {
if (outPutFileName.trim().equals("")) {
throw new NullPointerException("目標文件名為空。");
}
compressPic();
}

} catch (Exception e) {
flag = false;
e.printStackTrace();
return flag;
}

return flag;
}

// 圖片處理
private void compressPic() throws Exception {
try {
// 獲得源文件
file = new File(inPutFilePath + inPutFileName);
if (!file.exists()) {
throw new FileNotFoundException(inPutFilePath + inPutFileName
+ " 文件不存在！");
}
Image img = ImageIO.read(file);
// 判斷圖片格式是否正確
if (img.getWidth(null) == -1) {
throw new Exception("文件不可讀！");
} else {
int newWidth;
int newHeight;
// 判斷是否是等比縮放
if (ZIPImage.isScaleZoom == true) {
// 為等比縮放計算輸出的圖片寬度及高度
double rate1 = ((double) img.getWidth(null))
/ (double) outPutFileWidth + 0.1;
double rate2 = ((double) img.getHeight(null))
/ (double) outPutFileHeight + 0.1;

// 根據縮放比率大的進行縮放控制
double rate = rate1 > rate2 ? rate1 : rate2;

newWidth = (int) (((double) img.getWidth(null)) / rate);
newHeight = (int) (((double) img.getHeight(null)) / rate);

} else {
newWidth = outPutFileWidth; // 輸出的圖片寬度
newHeight = outPutFileHeight; // 輸出的圖片高度
}

BufferedImage tag = new BufferedImage((int) newWidth,
(int) newHeight, BufferedImage.TYPE_INT_RGB);

/*
* Image.SCALE_SMOOTH 的縮略演算法 生成縮略圖片的平滑度的 優先順序比速度高 生成的圖片質量比較好 但速度慢
*/
tag.getGraphics().drawImage(
img.getScaledInstance(newWidth, newHeight,
Image.SCALE_SMOOTH), 0, 0, null);

FileOutputStream out = new FileOutputStream(outPutFilePath
+ outPutFileName);

JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(out);
encoder.encode(tag);
out.close();

}
} catch (IOException ex) {
ex.printStackTrace();
}
}

/**
* 創建文件夾目錄
*
* @param filePath
* @return
* @throws Exception
*/
@SuppressWarnings("unused")
private static boolean mddir(String filePath) throws Exception {
boolean flag = false;
File f = new File(filePath);
if (!f.exists()) {
flag = f.mkdirs();
} else {
flag = true;
}
return flag;
}

/**
* 獲得文件名和擴展名
*
* @param fullFileName
* @return
* @throws Exception
*/
private String[] getFileNameAndExtName(String fullFileName)
throws Exception {
String[] fileNames = new String[2];
if (fullFileName.indexOf(".") == -1) {
throw new Exception("源文件名不正確！");
} else {
fileNames[0] = fullFileName.substring(0, fullFileName
.lastIndexOf("."));
fileNames[1] = fullFileName
.substring(fullFileName.lastIndexOf(".") + 1);
}
return fileNames;
}

public Image getSourceImage() throws IOException{
//獲得源文件
file = new File(inPutFilePath + inPutFileName);
if (!file.exists()) {
throw new FileNotFoundException(inPutFilePath + inPutFileName
+ " 文件不存在！");
}
Image img = ImageIO.read(file);
return img;
}

/*
* 獲得圖片大小
* @path ：圖片路徑
*/
public long getPicSize(String path) {
File file = new File(path);
return file.length();
}

}

//下面是測試程序

package com.sun.util.cyw;

import java.awt.Image;
import java.io.IOException;

public class ImageTest {
public static void main(String[] args) throws IOException {
ZIPImage zip=new ZIPImage("d:\\","1.jpg","d:\\test\\","處理後的圖片.jpg",false);
zip.setOutPutFileWidth(1000);
zip.setOutPutFileHeight(1000);

Image image=zip.getSourceImage();
long size=zip.getPicSize("d:\\1.jpg");
System.out.println("處理前的圖片大小 width:"+image.getWidth(null));
System.out.println("處理前的圖片大小 height:"+image.getHeight(null));
System.out.println("處理前的圖片容量:"+ size +" bit");

zip.compressImage();
}
}

⑩ java是怎麼實現等比例縮小圖片而不失真的啊

按照長寬的比例等比縮小，圖片最好用矢量圖片，不容易失真。。。