问题描述
我正在尝试创建一个Java程序，该程序创建一个密码，所有小写字母，小写字母和大写字母，小写字母和大写字母和数字，小写字母和大写字母以及数字和标点符号，并且该程序还必须创建一个密码，用户选择，并且必须根据用户选择的内容生成密码长度.我已经生成了供用户选择的密码选项，并提示他选择一个.我现在停留在如何创建上面提到的密码类型上.有人建议我使用ASCII值，然后将其转换为文本.我知道如何将它们转换为文本，但是它将显示数字，字母和标点符号.有什么方法可以只为小写字母生成ASCII值?另外，如何根据用户提供的长度生成密码?
I am trying to create a java program that creates a password, either all lowercase, lowercase and uppercase, lowercase and uppercase and numbers, lowercase and uppercase and numbers and punctuation and the program also has to create one of those password that the user picks and and has to generate a password length according to what the user picks. I have already generated the password options for the user to pick from and have prompted him to pick one. I am now stuck on how to create the password types that were mentioned above. One person suggested me to use ASCII values and then converting them to text. I know how to convert them to text, but it will display number, letters, and punctuations. Is there any way that I can just generate ASCII values for just lowercase letters? Also how will I generate a password according to the user's length that they give?
推荐答案
我使用了这个不变的类.
它使用构建器模式.
它不支持扩展.
I use this immutable class.
It uses the builder pattern.
It doesn't support extension.
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);
}
}
这是一个用法示例，
PasswordGenerator passwordGenerator = new PasswordGenerator.PasswordGeneratorBuilder()
.useDigits(true)
.useLower(true)
.useUpper(true)
.build();
String password = passwordGenerator.generate(8); // output ex.: lrU12fmM 75iwI90o
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