Java常用工具方法使用心得
- 每批一万处理大数据集合
- 判断字符串是否为数字
- 获取url的ip
- 解压、压缩文件夹
- 执行命令行命令
- SimpleDateFormat月日不显示0
- List汉字排序
- 删除空文件夹
- 获取文件夹下所有文件名
- 从字符串中提取数字
- 替换最后一个，仿replaceFirst方法
- 取两位小数
- 判断日期是否在某一段日期内
- 获取项目配置文件中的变量值
- txt文件最后一行文件内容覆写并追加
- 字符串中获取手机号
每批一万处理大数据集合
这种分批处理主要用于mysql数据处理上
List list = new ArrayList<>();
for(int i = 0 ;i< 51254;i ++){
list.add("pp"+i);
}
int size = list.size();
for (int i = 0; i < size; i+=Config.EVERY_NUM) {
int suffix = Config.EVERY_NUM;
if(i+Config.EVERY_NUM > size){
suffix = size - i;
}
List sublist = list.subList(i,i+suffix);
System.out.println(sublist.size());
} 输出
10000
10000
10000
10000
10000
1254判断字符串是否为数字
public static boolean isInteger(String str) {
Pattern pattern = Pattern.compile("^[-\\+]?[\\d]*$");
return pattern.matcher(str).matches();
}或者使用StringUtils自带的函数
public static boolean isNumeric(String str){
for (int i = str.length();--i>=0;){
if (!Character.isDigit(str.charAt(i))){
return false;
}
}
return true;
}获取url的ip
try {
String bankurl = "https://directbank.czbank.com/APPINSPECT/finance/creditCardApyOnlineCardSel.jsp";
URL url = new URL(bankurl);
InetAddress[] ips = InetAddress.getAllByName(url.getHost());
for (InetAddress ip : ips) {
System.out.println(ip.toString());
System.out.println("Address:" + ip.getHostAddress());
System.out.println("Name:" + ip.getHostName());
}
}catch (Exception e){
e.printStackTrace();
}这里获取到到ip应该是真实到ip，不经过dns，绕过cdn
解压、压缩文件夹
java自带的压缩api只能操作普通的文件，要想操作加密的zip文件，就得用到
<dependency>
<groupId>net.lingala.zip4jgroupId>
<artifactId>zip4jartifactId>
<version>1.3.2version>
dependency>具体代码如下：
zip4j–处理带密码的zip包
public static void unzip(File zipFile, String dest, String passwd) throws ZipException {
ZipFile zFile = new ZipFile(zipFile); // 首先创建ZipFile指向磁盘上的.zip文件
zFile.setFileNameCharset("GBK"); // 设置文件名编码，在GBK系统中需要设置
if (!zFile.isValidZipFile()) { // 验证.zip文件是否合法，包括文件是否存在、是否为zip文件、是否被损坏等
throw new ZipException("压缩文件不合法,可能被损坏.");
}
File destDir = new File(dest); // 解压目录
if (destDir.isDirectory() && !destDir.exists()) {
destDir.mkdir();
}
if (zFile.isEncrypted()) {
zFile.setPassword(passwd.toCharArray()); // 设置密码
}
zFile.extractAll(dest); // 将文件抽出到解压目录(解压)
}解压zip文件不带密码的到指定文件夹
Java实现zip文件解压[到指定目录]
/**
* 解压到指定目录
*
* @param zipPath
* @param descDir
*/
public static void unZipFiles2(String zipPath, String descDir) throws IOException {
unZipFilesNew(new File(zipPath), descDir);
delFolder(descDir + "/__MACOSX");
}
/**
* 解压文件到指定目录
* 解压后的文件名，和之前一致
*
* @param zipFile 待解压的zip文件
* @param descDir 指定目录
*/
@SuppressWarnings("rawtypes")
public static void unZipFilesNew(File zipFile, String descDir) throws IOException {
ZipFile zip = new ZipFile(zipFile, Charset.forName("UTF-8"));//解决中文文件夹乱码
String name = zip.getName().substring(zip.getName().lastIndexOf('\\') + 1, zip.getName().lastIndexOf('.'));
File pathFile = new File(descDir);
if (!pathFile.exists()) {
pathFile.mkdirs();
}
for (Enumeration entries = zip.entries(); entries.hasMoreElements(); ) {
ZipEntry entry = (ZipEntry) entries.nextElement();
String zipEntryName = entry.getName();
InputStream in = zip.getInputStream(entry);
String outPath = (descDir + "/" + zipEntryName).replaceAll("\\*", "/");
// 判断路径是否存在,不存在则创建文件路径
File file = new File(outPath.substring(0, outPath.lastIndexOf('/')));
if (!file.exists()) {
file.mkdirs();
}
// 判断文件全路径是否为文件夹,如果是上面已经上传,不需要解压
if (new File(outPath).isDirectory()) {
continue;
}
// 输出文件路径信息
// System.out.println(outPath);
FileOutputStream out = new FileOutputStream(outPath);
byte[] buf1 = new byte[1024];
int len;
while ((len = in.read(buf1)) > 0) {
out.write(buf1, 0, len);
}
in.close();
out.close();
}
System.out.println("******************解压完毕********************");
return;
}压缩文件不带密码的
/**
* 压缩文件夹
*
* @param dirPath
* @param zipName http://www.jb51.net/article/115212.htm
*/
public static void zipFiles(String dirPath, String zipName) {
List srcfile = getFiles(dirPath);
byte[] buf = new byte[1024];
try {
//ZipOutputStream类：完成文件或文件夹的压缩
File zipFile = new File(zipName);
ZipOutputStream out = new ZipOutputStream(new FileOutputStream(zipFile));
for (int i = 0; i < srcfile.size(); i++) {
File file = new File(srcfile.get(i));
FileInputStream in = new FileInputStream(file);
out.putNextEntry(new ZipEntry(file.getName()));
int len;
while ((len = in.read(buf)) > 0) {
out.write(buf, 0, len);
}
out.closeEntry();
in.close();
}
out.close();
System.out.println("压缩完成.");
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
} 执行命令行命令
Runtime.getRuntime().exec()执行重定向命令方法
private void moveFile(String srcFilePath, String destFilePath) {
try {
Runtime runtime = Runtime.getRuntime();
String[] cmd = {"sh", "-c", "mv " + srcFilePath + " " + destFilePath};
Process outputCsvDecrypt = runtime.exec(cmd);
int outputExitVal = outputCsvDecrypt.waitFor();
System.out.println("移动结果" + outputExitVal);
if (outputExitVal == 0) {
System.out.println(srcFilePath + "移动成功");
}
} catch (Exception e) {
e.printStackTrace();
}
}SimpleDateFormat月日不显示0
https://blog.csdn.net/KingWTD/article/details/48089111
SimpleDateFormat format = new SimpleDateFormat("yyyyMd");
System.out.println(format.format(new Date()));
2018511List汉字排序
https://blog.csdn.net/jky_yihuangxing/article/details/50736154
List list=new ArrayList<>();
list.add("河南");
list.add("江苏");
list.add("福建");
list.add("甘肃");
list.add("北京");
Collections.sort(list, Collator.getInstance(java.util.Locale.CHINA)); 删除空文件夹
/**
* 删除空文件夹
* @param folderPath
*/
public static void delFolder(String folderPath) {
try {
//实例化File
File myFilePath = new File(folderPath);
myFilePath.delete(); //删除空文件夹
} catch (Exception e) {
e.printStackTrace();
}
}获取文件夹下所有文件名
Java-读取某个目录下所有文件、文件夹和3种从文件路径中获取文件名的方法
public static ArrayList getFiles(String path) {
ArrayList files = new ArrayList();
File file = new File(path);
File[] tempList = file.listFiles();
for (int i = 0; i < tempList.length; i++) {
if (tempList[i].isFile()) {
files.add(tempList[i].toString());
}
}
return files;
} 从字符串中提取数字
java从字符串中提取数字
String regEx = "[^0-9]";
Pattern p = Pattern.compile(regEx);
Matcher m = p.matcher(str);
String id = m.replaceAll("").trim();
System.out.println("--------------id" + id);
以上输入为
group.data163.data或者
group.data163输出为
163替换最后一个，仿replaceFirst方法
https://stackoverflow.com/questions/2282728/java-replacelast
public static String replaceLast(String text, String regex, String replacement) {
return text.replaceFirst("(?s)(.*)" + regex, "$1" + replacement);
}
public static void main(String[] args) {
System.out.println(replaceLast("foo AB bar AB AB car AB done", "AB", "--"));
}以上输出内容为
foo AB bar AB AB car -- done取两位小数
int a = 2;
double b = 10000;
DecimalFormat decimalFormat=new DecimalFormat("######0.00");
System.out.println(decimalFormat.format(a/b*100)+"%");
输出：0.02%判断日期是否在某一段日期内
String dateStr= "02/11/2017 18:36:57";
String startDate = "2017-02-11";
String endDate = "2017-02-13";
System.out.println(Utils.getFormatDate(dateStr,startDate,endDate));
输出：在public static boolean getFormatDate(String dateStr, String inputDate) {
boolean isIncurrentDay = false;
SimpleDateFormat format = new SimpleDateFormat("MM/dd/yyyy HH:mm:ss");
try {
SimpleDateFormat format2 = new SimpleDateFormat("yyyy-MM-dd");
String fileDate = format2.format(format.parse(dateStr));
if (fileDate.equals(inputDate)) {
System.out.println("在");
isIncurrentDay = true;
} else {
System.out.println("不在");
isIncurrentDay = false;
}
} catch (ParseException e) {
e.printStackTrace();
}
return isIncurrentDay;
}
public static boolean getFormatDate(String dateStr, String startDate, String endDate) {
boolean isInDuration = false;
try {
SimpleDateFormat format = new SimpleDateFormat("MM/dd/yyyy HH:mm:ss");
SimpleDateFormat format2 = new SimpleDateFormat("yyyy-MM-dd");
Date dateS = format2.parse(format2.format(format.parse(dateStr)));
Date startS = format2.parse(startDate);
Date endS = format2.parse(endDate);
if (!dateS.after(endS) && !dateS.before(startS)) {
System.out.println("在");
isInDuration = true;
} else {
System.out.println("不在");
isInDuration = false;
}
} catch (ParseException e) {
e.printStackTrace();
}
return isInDuration;
}获取项目配置文件中的变量值
第一种
Properties property = new Properties();
try {
property.load(new FileInputStream("你的文件位置"));
} catch (IOException e) {
e.printStackTrace();
}
String value = property.getProperty("你的属性的key");第二种，推荐使用
java.util.ResourceBundle bundle = java.util.ResourceBundle.getBundle("email");
String keystore = bundle.getString("mysql.decrystore"); //获取值txt文件最后一行文件内容覆写并追加
public static void rewriteendline(String filepath, String string)
throws Exception {
RandomAccessFile file = new RandomAccessFile(filepath, "rw");
long len = file.length();
long start = file.getFilePointer();
long nextend = start + len - 1;
int i = -1;
file.seek(nextend);
byte[] buf = new byte[1];
while (nextend > start) {
i = file.read(buf, 0, 1);
if (buf[0] == '\r') {
file.setLength(nextend - start);
break;
}
nextend--;
file.seek(nextend);
}
file.close();
writeendline(filepath, string);
}
public static void writeendline(String filepath, String string)
throws Exception {
RandomAccessFile file = new RandomAccessFile(filepath, "rw");
long len = file.length();
long start = file.getFilePointer();
long nextend = start + len - 1;
byte[] buf = new byte[1];
file.seek(nextend);
file.read(buf, 0, 1);
if (buf[0] == '\n')
file.writeBytes(string);
else
file.writeBytes("\r\n" + string);
file.close();
}字符串中获取手机号
/**
* 只取字符串中11位的数字是否为手机号，如果有多个，逗号隔开
* @param text
* @return
*/
public static String getPhone11(String text){
Pattern pattern = Pattern.compile("(?);
Matcher matcher = pattern.matcher(text);
StringBuffer bf = new StringBuffer(64);
while (matcher.find()) {
bf.append(matcher.group()).append(",");
}
int len = bf.length();
if (len > 0) {
bf.deleteCharAt(len - 1);
}
return bf.toString();
}
/**
* 查询符合的手机号码，包括从12位数字中截取手机号
* @param str
*/
public static void checkCellphone(String str){
// 将给定的正则表达式编译到模式中
Pattern pattern = Pattern.compile("((13[0-9])|(14[5|7])|(15([0-3]|[5-9]))|(18[0,5-9]))\\d{8}");
// 创建匹配给定输入与此模式的匹配器。
Matcher matcher = pattern.matcher(str);
//查找字符串中是否有符合的子字符串
while(matcher.find()){
//查找到符合的即输出
System.out.println("查询到一个符合的手机号码："+matcher.group());
}
}
/**同上
**/
private static String checkNum(String num){
if(num == null || num.length() == 0){return "";}
Pattern pattern = Pattern.compile("(?);
Matcher matcher = pattern.matcher(num);
StringBuffer bf = new StringBuffer(64);
while (matcher.find()) {
bf.append(matcher.group()).append(",");
}
int len = bf.length();
if (len > 0) {
bf.deleteCharAt(len - 1);
}
return bf.toString();
}
private static boolean isNumLegal(String str) throws PatternSyntaxException {
String regExp = "^((13[0-9])|(15[^4])|(18[0,2,3,5-9])|(17[0-8])|(147))\\d{8}$";
Pattern p = Pattern.compile(regExp);
Matcher m = p.matcher(str);
return m.matches();
}