com.jeesuite.filesystem.sdk.fdfs.FastdfsUtils Maven / Gradle / Ivy
/**
*
*/
package com.jeesuite.filesystem.sdk.fdfs;
import io.netty.buffer.ByteBuf;
import io.netty.util.CharsetUtil;
import java.util.Collection;
import java.util.List;
import static io.netty.util.CharsetUtil.UTF_8;
/**
* 帮助类
*
* @author liulongbiao
*/
public final class FastdfsUtils {
private FastdfsUtils() {
}
/**
* 判断字符串为空
*
* @param content
* @return
*/
public static boolean isEmpty(String content) {
return content == null || content.isEmpty();
}
/**
* 判断集合是否为空
*
* @param coll
* @return
*/
public static boolean isEmpty(Collection coll) {
return coll == null || coll.isEmpty();
}
/**
* 获取列表头元素
*
* @param list
* @return
*/
public static T first(List list) {
return isEmpty(list) ? null : list.get(0);
}
/**
* 给 ByteBuf 写入定长字符串
*
* 若字符串长度大于定长，则截取定长字节；若小于定长，则补零
*
* @param buf
* @param content
* @param length
*/
public static void writeFixLength(ByteBuf buf, String content, int length) {
byte[] bytes = content.getBytes(CharsetUtil.UTF_8);
int blen = bytes.length;
int wlen = blen > length ? length : blen;
buf.writeBytes(bytes, 0, wlen);
if (wlen < length) {
buf.writeZero(length - wlen);
}
}
/**
* 读取固定长度的字符串(修剪掉补零的字节)
*
* @param in
* @param length
* @return
*/
public static String readString(ByteBuf in, int length) {
return in.readBytes(length).toString(UTF_8).trim();
}
/**
* 读取字符串(修剪掉补零的字节)
*
* @param in
* @return
*/
public static String readString(ByteBuf in) {
return in.toString(UTF_8);
}
/**
* 获取文件扩展名
*
* @param filename
* @return
*/
public static String getFileExt(String filename) {
if (filename == null) {
return "";
}
int idx = filename.lastIndexOf('.');
return idx == -1 ? "" : filename.substring(idx + 1).toLowerCase();
}
/**
* 获取文件扩展名
*
* @param filename
* @return
*/
public static String getFileExt(String filename, String defaultExt) {
String fileExt = getFileExt(filename);
return isEmpty(fileExt) ? defaultExt : fileExt;
}
}