arturotena

// Para actualizar un campo tipo blob, ya sea de bytes o de texto / To update a blob field, either byte or text

Class.forName(driver);
Connection con = DriverManager.getConnection(...)
Statement stmt = con.createStatement(ResultSet.TYPE_FORWARD_ONLY, ResultSet.CONCUR_UPDATABLE);
String query = "SELECT info FROM tabla WHERE id = 1";
ResultSet rs = stmt.executeQuery(query);
rs.next();
if (esBinario) {
  rs.updateBytes(campo, contenidoBytes);

arturotena

/*
 * Código fácil para cifrar y descifrar en Java ("encriptar" y "desencriptar").
 * No ha sido auditado, ni garantizo su seguridad.
 */

import java.security.MessageDigest;
import javax.crypto.Cipher;
import javax.crypto.spec.SecretKeySpec;

public byte[] cifra(String sinCifrar) throws Exception {

arturotena

/*
Copyright 2014 Arturo Tena
 
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
 
    http://www.apache.org/licenses/LICENSE-2.0
 
Unless required by applicable law or agreed to in writing, software

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@Override
public boolean equals(Object other) {
	if (this == other) return true;
	if (!(other instanceof MyClass)) return false;
	final MyClass that = (MyClass) other;
	return this.intField == that.intField &&
	       this.booleanField == that.booleanField &&
	       (this.stringField == null ? this.stringField == null : this.stringField.equals(that.stringField)) &&
	       (this.objectField == null ? this.objectField == null : this.objectField.equals(that.objectField));
}

arturotena

class Fechas implements Iterable<Timestamp> {
    FechasIter iter;
    
    Fechas(int field, int amount) {
        this.iter = new FechasIter(field, amount);
    }
    
    public Iterator<Timestamp> iterator() {
        return iter;
    }

arturotena

// Quick-and-dirty way to count the lines of Java source code of a project
System.out.println(Files.walk(Paths.get("."))
        .map(e -> e.toFile())
        .filter(f -> f.isFile() && f.canRead())
        .filter(f -> f.getName().endsWith(".java"))
        .mapToLong(f -> {
            try { return new BufferedReader(new FileReader( f )).lines().count();
            } catch (Exception ex) { throw new RuntimeException(ex); }
        })
        .reduce(0, (acc, current) -> acc + current));

arturotena

# Abre un shell de root en OS X
# El usuario actual debe ser administrador
sudo -s
# La contraseña que solicita es del usuario actual.

arturotena

# Encuentra archivos con cierto nombre en OS X
find / -name "java"

arturotena

// I haven't tested it
public int compareTo(MyClass that) {
	if (this == that) return 0;
	int comp = Integer.valueOf(this.intField).compareTo(that.intField);
	if (comp != 0) return comp;
	comp = this.stringField == null ? -1 : this.claveRed.compareTo(that.stringField);
	if (comp != 0) return comp;
	comp = Boolean.valueOf(this.booleanField).compareTo(that.booleanField);
	if (comp != 0) return comp;
	comp = this.objectField == null ? -1 : this.claveRed.compareTo(that.objectField);

arturotena

/** Remove all entries except the given keys */
private <K,V>void removeAllExcept(Map<K,V> map, K... keys) {
  Map<K,V> objs = new HashMap<K,V>(keys.length);
  for (K key : keys)
    objs.put(key, map.get(key));
  map.clear();
  map.putAll(objs);
}

/** Remove all entries except the given keys */