Java Template

file.java

//逐行读取UTF-8文件
private String readFile( String file ) throws IOException {
    Reader readerFile = new InputStreamReader( new FileInputStream(file), "UTF-8");
    BufferedReader reader = new BufferedReader( readerFile );
    String         line = null;
    StringBuilder  stringBuilder = new StringBuilder();
    String         ls = System.getProperty("line.separator");

    while( ( line = reader.readLine() ) != null ) {
        stringBuilder.append( line );
        stringBuilder.append( ls );
    }

    return stringBuilder.toString();
}

//删除文件
public static void deleteFile(File file) {
	File[] fileArray = file.listFiles();
	if (fileArray.length > 0) {
		for (File element : fileArray) {
			if (element.isFile()) {
				if (element.delete()) {
					System.out.println("Delete Successfully" + " in: " + element.getAbsolutePath());
				} else {
					System.out.println("Delete False" + " in: " + element.getAbsolutePath());
				}
			} else {
				deleteFile(element);
			}
		}
	}
	if (file.delete()) {
		System.out.println("Delete Successfully" + " in: " + file.getAbsolutePath());
	} else {
		System.out.println("Delete False" + " in: " + file.getAbsolutePath());
	}
}

//压缩文件
public static void zipMultiFile(String filepath, String zippath) {
	try {
		File file = new File(filepath);// 要被压缩的文件夹
		File zipFile = new File(zippath);
		ZipOutputStream zipOut = new ZipOutputStream(new FileOutputStream(zipFile));
		zipOut.setEncoding("gbk");
		if (file.isDirectory()) {
			File[] files = file.listFiles();
			for (File file2 : files) {
				InputStream input = new FileInputStream(file2);
				zipOut.putNextEntry(new ZipEntry(file.getName() + File.separator + file2.getName()));
				int temp = 0;
				while ((temp = input.read()) != -1) {
					zipOut.write(temp);
				}
				input.close();
			}
		}
		zipOut.close();
	} catch (Exception e) {
		e.printStackTrace();
	}
}

jsoup.java

// parse node tag
StringBuilder pureRecommend = new StringBuilder();
Document doc = Jsoup.parse(htmlRecommend);
Element body = doc.body();
List<Node> childNodes = body.childNodes();
for (Node node : childNodes) {
    if (node.nodeName().equalsIgnoreCase("#text") && StringUtils.isNotBlank(node.outerHtml())) {
        String pureText = ((TextNode) node).text().replace("\u00a0", " ");
        pureRecommend.append(pureText);
    }
    if (node.nodeName().equalsIgnoreCase("a") && StringUtils.isNotBlank(node.outerHtml())) {
        pureRecommend.append(((Element)node).text());
    }
}
return pureRecommend.toString();

// parse img tag
Document doc = Jsoup.connect("www.abc.com").get();
Elements img = doc.getElementsByTag("img");
for (Element el : img) {
  String src = el.absUrl("src");
  System.out.println("Image Found!");
  System.out.println("src attribute is : "+src);
}

// replace &nbps
node.text().replace("\u00a0", " ")

多线程.java

public class TraderApplicationTest {

    public static void main(String[] args) {
        Lock lock = new Lock();
        Worker worker1 = new Worker(lock);
        worker1.start();
        Worker worker2 = new Worker(lock);
        worker2.start();
    }

    public static class Lock {
        private final List<TradeOrder> tradeOrders;
        public Lock() {
            this.tradeOrders = new ArrayList<>();
        }
        public void plusOne() {
            synchronized (tradeOrders) {
                try {
                    System.out.println("开始");
                    tradeOrders.add(new TradeOrder());
                    Thread.sleep(3000);
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
        }
        public void printLength() {
            System.out.println("数量为" + tradeOrders.size());
        }
    }


    public static class Worker extends Thread {
        private final Lock lock;
        public Worker(Lock lock) {
            this.lock = lock;
        }
        public void run() {
            try {
                lock.plusOne();
                lock.printLength();
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    }

}

随机数.java

public static void main(String[] args) {
    Integer[] arr = new Integer[10];
    for (int i = 0; i < arr.length; i++) {
        arr[i] = i + 1;
    }
    Collections.shuffle(Arrays.asList(arr));
    System.out.println(Arrays.toString(arr));
}