![[java] password generator Empty](https://2img.net/i/empty.gif)
Code:
package chobit;
import java.util.ArrayList;
import java.util.List;
import java.util.Random;
public final class PasswordGenerator {
private static final String LOWER = "abcdefghijklmnopqrstuvwxyz";
private static final String UPPER = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
private static final String DIGITS = "0123456789";
private static final String PUNCTUATION = "!@#$%&*()_+-=[]|,./?><";
private boolean useLower;
private boolean useUpper;
private boolean useDigits;
private boolean usePunctuation;
private PasswordGenerator() {
throw new UnsupportedOperationException("Empty constructor is not supported.");
}
private PasswordGenerator(PasswordGeneratorBuilder builder) {
this.useLower = builder.useLower;
this.useUpper = builder.useUpper;
this.useDigits = builder.useDigits;
this.usePunctuation = builder.usePunctuation;
}
public static class PasswordGeneratorBuilder {
private boolean useLower;
private boolean useUpper;
private boolean useDigits;
private boolean usePunctuation;
public PasswordGeneratorBuilder() {
this.useLower = false;
this.useUpper = false;
this.useDigits = false;
this.usePunctuation = false;
}
/**
* Set true in case you would like to include lower characters (abc...xyz).
* Default false.
*
* @param useLower
* true in case you would like to include lower characters
* (abc...xyz). Default false.
* @return the builder for chaining.
*/
public PasswordGeneratorBuilder useLower(boolean useLower) {
this.useLower = useLower;
return this;
}
/**
* Set true in case you would like to include upper characters (ABC...XYZ).
* Default false.
*
* @param useUpper
* true in case you would like to include upper characters
* (ABC...XYZ). Default false.
* @return the builder for chaining.
*/
public PasswordGeneratorBuilder useUpper(boolean useUpper) {
this.useUpper = useUpper;
return this;
}
/**
* Set true in case you would like to include digit characters (123..). Default
* false.
*
* @param useDigits
* true in case you would like to include digit characters (123..).
* Default false.
* @return the builder for chaining.
*/
public PasswordGeneratorBuilder useDigits(boolean useDigits) {
this.useDigits = useDigits;
return this;
}
/**
* Set true in case you would like to include punctuation characters (!@#..).
* Default false.
*
* @param usePunctuation
* true in case you would like to include punctuation characters
* (!@#..). Default false.
* @return the builder for chaining.
*/
public PasswordGeneratorBuilder usePunctuation(boolean usePunctuation) {
this.usePunctuation = usePunctuation;
return this;
}
/**
* Get an object to use.
*
* @return the {@link gr.idrymavmela.business.lib.PasswordGenerator} object.
*/
public PasswordGenerator build() {
return new PasswordGenerator(this);
}
}
/**
* This method will generate a password depending the use* properties you
* define. It will use the categories with a probability. It is not sure that
* all of the defined categories will be used.
*
* @param length
* the length of the password you would like to generate.
* @return a password that uses the categories you define when constructing the
* object with a probability.
*/
public String generate(int length) {
// Argument Validation.
if (length <= 0) {
return "";
}
// Variables.
StringBuilder password = new StringBuilder(length);
Random random = new Random(System.nanoTime());
// Collect the categories to use.
List<String> charCategories = new ArrayList<>(4);
if (useLower) {
charCategories.add(LOWER);
}
if (useUpper) {
charCategories.add(UPPER);
}
if (useDigits) {
charCategories.add(DIGITS);
}
if (usePunctuation) {
charCategories.add(PUNCTUATION);
}
// Build the password.
for (int i = 0; i < length; i++) {
String charCategory = charCategories.get(random.nextInt(charCategories.size()));
int position = random.nextInt(charCategory.length());
password.append(charCategory.charAt(position));
}
return new String(password);
}
}use example :
Code:
PasswordGenerator passwordGenerator = new PasswordGenerator.PasswordGeneratorBuilder().useDigits(true)
.useLower(true).useUpper(true).build();
String password = passwordGenerator.generate(8);
System.out.println(password);