HoweChen

/**
 * @author howechen
 */
@Component
public class SystemCommandExecutor {

    private static final Logger logger = LoggerFactory.getLogger(SystemCommandExecutor.class);
    private ExecuteWatchdog watchdog = new ExecuteWatchdog(60000);
    private PluginExecuteResultHandler resultHandler = new PluginExecuteResultHandler();

HoweChen

public String toString() throws Exception {
  ObjectMapper mapper = new ObjectMapper();
  mapper.setSerializationInclusion(JsonInclude.Include.NON_NULL);
  String result;
  try {
    result = mapper.writeValueAsString(this);
  } catch (JsonProcessingException e) {
    throw new Exception("Cannot transfer backend server info to json string");
  }

HoweChen

public static <K, V> Map<K, V> zipToMap(List<K> keyList, List<V> valueList) throws Exception {
  Map<K, V> result = new HashMap<>();
  Iterator<K> keyIterator = keyList.iterator();
  Iterator<V> valueIterator = valueList.iterator();
  while (keyIterator.hasNext() && valueIterator.hasNext()) {
    result.put(keyIterator.next(), valueIterator.next());
  }
  if (keyIterator.hasNext() || valueIterator.hasNext()) {
    throw new Exception("The keyList and valueList size doesn't match.");
  }

HoweChen

// https://blog.csdn.net/java_zjh/article/details/80915655

public final class AesUtils {
    private static final String CHARSET_NAME = "UTF-8";
    private static final String AES_NAME = "AES";
    public static final String ALGORITHM = "AES/CBC/PKCS7Padding";

    static {
        Security.addProvider(new BouncyCastleProvider());
    }

HoweChen

// both are good to use, but cannot tolerate the situation when key or value inside the list is null

public static <K, V> Map<K, V> zipToMap(List<K> keys, List<V> values) {
    return IntStream.range(0, keys.size()).boxed()
            .collect(Collectors.toMap(keys::get, values::get));
}



public static <K, V> Map<K, V> zipToMap(List<K> keys, List<V> values) {

HoweChen

// should use org.apache.commons.lang3
EnumUtils.isValidEnum(enumxxx.class,str);

HoweChen

Map<String, List<Long>> capitalKeyToValueMap = procDefInfoDto.getPermissionToRole()
  .entrySet()
  .stream()
  .collect(Collectors.toMap(stringListEntry -> stringListEntry.getKey().toUpperCase(), Map.Entry::getValue));

HoweChen

public class Test {
 
    public static void main(String[] args) {
        List<String> list1 = new ArrayList<String>();
        list1.add("1");
		list1.add("2");
		list1.add("3");
		list1.add("5");
		list1.add("6");
 

HoweChen

public static strictfp String humanReadableByteCount(long bytes, boolean si) {
    int unit = si ? 1000 : 1024;
    long absBytes = bytes == Long.MIN_VALUE ? Long.MAX_VALUE : Math.abs(bytes);
    if (absBytes < unit) return bytes + " B";
    int exp = (int) (Math.log(absBytes) / Math.log(unit));
    long th = (long) (Math.pow(unit, exp) * (unit - 0.05));
    if (exp < 6 && absBytes >= th - ((th & 0xfff) == 0xd00 ? 52 : 0)) exp++;
    String pre = (si ? "kMGTPE" : "KMGTPE").charAt(exp - 1) + (si ? "" : "i");
    if (exp > 4) {
        bytes /= unit;

HoweChen

List<?> list = new ArrayList<>( myQueue );

? can be be the class you want to transfer