Java学习笔记――IO操作之以图片地址下载图片 (一)

以图片地址下载图片
读取给定图片文件的内容，用FileInputStream

[java]
public static byte[] mReaderPicture(String filePath) {
byte[] arr = null;
try {
File file = new File(filePath);
FileInputStream fReader = new FileInputStream(file);
arr = new byte[1024*100];
fReader.read(arr);
} catch (Exception e) {
// TODO: handle exception
e.printStackTrace();
}
return arr;
}

public static byte[] mReaderPicture(String filePath) {
byte[] arr = null;
try {
File file = new File(filePath);
FileInputStream fReader = new FileInputStream(file);
arr = new byte[1024*100];
fReader.read(arr);
} catch (Exception e) {
// TODO: handle exception
e.printStackTrace();
}
return arr;
}

根据byte数组，创建一张新图。
[java]
public static void mWriterPicture(String newFileName,byte[] b){
try {
File file = new File(newFileName);
FileOutputStream fStream = new FileOutputStream(file);
fStream.write(b);
fStream.close();
System.out.println("图片创建成功 "+b.length);
} catch (Exception e) {
// TODO: handle exception
}
}

public static void mWriterPicture(String newFileName,byte[] b){
try {
File file = new File(newFileName);
FileOutputStream fStream = new FileOutputStream(file);
fStream.write(b);
fStream.close();
System.out.println("图片创建成功 "+b.length);
} catch (Exception e) {
// TODO: handle exception
}
}

获取指定网址的图片，返回其byte[]
[java]
public static byte[] mReaderPictureToInternet(String strUr1){
byte[] imgData = null;
URL url;
try {
url = new URL(strUr1);
URLConnection connection = url.openConnection();
int length = (int)connection.getContentLength();
InputStream is = connection.getInputStream();
if (length!=-1) {
imgData = new byte[length];
byte[] temp = new byte[500*1024];
int readLen = 0;
int destPos = 0;
while ((readLen = is.read(temp))>0) {
System.arraycopy(temp, 0, imgData, destPos, readLen);
//arraycopy(Object src, int srcPos, Object dest, int destPos, int length)
//从指定源数组中复制一个数组，复制从指定的位置开始，到目标数组的指定位置结束
destPos+=readLen;
}
}
return imgData;
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return imgData;
}

public static byte[] mReaderPictureToInternet(String strUr1){
byte[] imgData = null;
URL url;
try {
url = new URL(strUr1);
URLConnection connection = url.openConnection();
int length = (int)connection.getContentLength();
InputStream is = connection.getInputStream();
if (length!=-1) {
imgData = new byte[length];
byte[] temp = new byte[500*1024];
int readLen = 0;
int destPos = 0;
while ((readLen = is.read(temp))>0) {
System.arraycopy(temp, 0, imgData, destPos, readLen);
//arraycopy(Object src, int srcPos, Object dest, int destPos, int length)
//从指定源数组中复制一个数组，复制从指定的位置开始，到目标数组的指定位置结束
destPos+=readLen;
}
}
return imgData;
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return imgData;
}

直接获取指定网址的图片
[java]
public static void DownPictureToInternet(String filePath,String strUr1){