【发布时间】：2020-06-05 22:08:40
【问题描述】：
你好，我是 JAVA 编程语言的新手，我已经学习了很多 Java 教程，但我发现很难让它在这段代码中工作面向对象编程。 我有 2 个程序，第一个是程序方式。我使用了一个字符串数组来存储两个 dates.toString (short, long) 和两个 Hashes(dates.toString[long,short])
import java.math.BigInteger;
import java.time.format.DateTimeFormatter;
import java.nio.charset.StandardCharsets;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.time.LocalDateTime;
import java.util.Calendar;
import java.util.Date;
import org.hsqldb.Trace;
public class Hashing {
private LocalDateTime justNow;
/**
* Full Date and Time
*/
private String fullDate;
/**
* Current date and time cropped
*/
private String currentDateCropped;
/**
* Hashing Function of FullDate HASHED
*/
private String showFullDate;
/**
* Hashing Function of DateCropped HASHED
*/
private String showCurrentDateCropped;
/**
* Arguments:
* Refactoring procedure below with Object oriented Programming
* @return String Array of 2 results [0] Limited Date [1]
* FullDate
*/
public string getDate() {
setFullDateNow();
System.out.println(getFullDate().toString(true));
DateTimeFormatter dtf = DateTimeFormatter.ofPattern("dd/MM/yyyy");
DateTimeFormatter dtfFull = DateTimeFormatter.ofPattern("dd/MM/yyyy | HH");
LocalDateTime now;
now = LocalDateTime.now();
System.out.println(dtf.format(now));
System.out.println(dtfFull.format(now));
Date date = java.util.Calendar.getInstance().getTime();
String[] dateStr = new String[2];
dateStr[0] = " ";
dateStr[1] = " ";
dateStr[0] = dtf.format(now);
dateStr[1] = dtfFull.format(now);
return dateStr;
}
public static byte[] getSHA(String input) throws NoSuchAlgorithmException {
// Static getInstance method is called with hashing SHA
MessageDigest md = MessageDigest.getInstance("SHA-256");
// digest() method called
// to calculate message digest of an input
// and return array of byte
return md.digest(input.getBytes(StandardCharsets.UTF_8));
}
public static String toHexString(byte[] hash) {
// Convert byte array into signum representation
BigInteger number = new BigInteger(1, hash);
// Convert message digest into hex value
StringBuilder hexString = new StringBuilder(number.toString(16));
// Pad with leading zeros
while (hexString.length() < 32) {
hexString.insert(0, '0');
}
return hexString.toString();
}
// Driver code
public Hashing() {
try {
//remove
System.out.println("HashCode Generated by SHA-256 for:");
String[] currentDate = getDate();
String[] result = new String[4];
result[0] = currentDate[0];
result[1] = currentDate[1];
result[2] = toHexString(getSHA(currentDate[0]));
result[3] = toHexString(getSHA(currentDate[1]));
System.out.println("\n" + currentDate[0] + " : " + toHexString(getSHA(currentDate[0])));
} // For specifying wrong message digest algorithms
catch (NoSuchAlgorithmException e) {
System.out.println("Exception thrown for incorrect algorithm: " + e);
}
return myString;
}
public static void main(String args[]) {
Hashing();
}
}
另一个重构的代码块是：
import java.math.BigInteger;
import java.time.format.DateTimeFormatter;
import java.nio.charset.StandardCharsets;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.time.LocalDateTime;
import java.util.Calendar;
import java.util.Date;
import org.hsqldb.Trace;
public class Hashing {
private LocalDateTime justNow;
/**
* Full Date and Time
*/
private String fullDate;
/**
* Current date and time cropped
*/
private String currentDateCropped;
/**
* Hashing Function of FullDate HASHED
*/
private String varFullDateHash;
/**
* Hashing Function of DateCropped HASHED
*/
private String varCurrentDateCroppedHash;
/**
* Initializer of what time is now on the constructor (Netbeans Warning)
*/
public void initComponentstatic() {
setFullDateNow();
}
/**
* Getter for getting Full Date
*
* @return LocalDateTime Just NOW!
*/
public LocalDateTime getFullDate() {
LocalDateTime inner = this.justNow;
return inner;
}
/**
* Setter for Setting a Custom Date to private variable justNow
*
* Void justNOW=CustomDate
*/
public void setFullDate(LocalDateTime MyDate) {
LocalDateTime inner = MyDate;
this.justNow = inner;
}
/**
* Setter for Setting a Current Date to private variable justNow
*
* Void justNOW=now()
*/
public void setFullDateNow() {
LocalDateTime now;
now = LocalDateTime.now();
this.justNow = now;
}
/**
* Setter for Setting a Current Date to private variable justNow
*
* Void justNOW=now()
*/
//@Override It doesn't Need to be overriden because it has a a parameter (Boolean)
public String toString(boolena full) {
DateTimeFormatter dtf;
String TEMP;
LocalDateTime currentDate;
if (full) {
dtf = DateTimeFormatter.ofPattern(
"dd/MM/yyyy | HH:mm:ss:SS");
} else {
dtf = DateTimeFormatter.ofPattern(
"dd/MM/yyyy | HH");
}
/** This doesn't work
try {
if (this.justNow = null) {
System.out.println("justNow Inited");
} else {
System.out.println("justNow Empty");
}
} catch (Exception e) {
}*/
currentDate = this.justNow;
TEMP = currentDate.format(dtf);
return TEMP; //To change body of generated methods, choose Tools | Templates.
}
/**
* Arguments:
* Refactoring procedure below with Object oriented Programming
* The variables are stored in this new OOP code as private variables, and accessed through getters and setters.
*/
/**
* public string getDate() {
* setFullDateNow();
*
* System.out.println(getFullDate().toString(true));
* /**
* DateTimeFormatter dtf = DateTimeFormatter.ofPattern("dd/MM/yyyy |
* HH");
* DateTimeFormatter dtfFull = DateTimeFormatter.ofPattern("dd/MM/yyyy |
* HH:mm:ss:SS");
*
* LocalDateTime now;
* now = LocalDateTime.now();
*
* System.out.println(dtf.format(now));
* System.out.println(dtfFull.format(now));
* Date date = java.util.Calendar.getInstance().getTime();
* String[] dateStr = new String[2];
* dateStr[0] = " ";
* dateStr[1] = " ";
* dateStr[0] = dtf.format(now);
* dateStr[1] = dtfFull.format(now);
*
* return dateStr;
*
* }
*/
public static byte[] getSHA(String input) throws NoSuchAlgorithmException {
// Static getInstance method is called with hashing SHA
MessageDigest md = MessageDigest.getInstance("SHA-256");
// digest() method called
// to calculate message digest of an input
// and return array of byte
return md.digest(input.getBytes(StandardCharsets.UTF_8));
}
public static String toHexString(byte[] hash) {
// Convert byte array into signum representation
BigInteger number = new BigInteger(1, hash);
// Convert message digest into hex value
StringBuilder hexString = new StringBuilder(number.toString(16));
// Pad with leading zeros
while (hexString.length() < 32) {
hexString.insert(0, '0');
}
return hexString.toString();
}
// Driver code
public Hashing() {
try {
//remove
initComponentstatic();
DateTimeFormatter dtf;
dtf = DateTimeFormatter.ofPattern(
"dd/MM/yyyy | HH:mm:ss:SS");
//System.out.println(getFullDate().toString(true));
String myString = getFullDate().toString(true);
System.out.println(myString);
fullDate=getFullDate().toString(true);
currentDateCropped=getFullDate().toString(false);
varFullDateHash=toHexString(getSHA(fullDate));;
varCurrentDateCroppedHash=toHexString(getSHA(fullDateCropped));;;
System.out.println("\n" + fullDate + " : " + varFullDateHash);
System.out.println("\n" + currentDateCropped + " : " + varCurrentDateCroppedHash);
*/
} // For specifying wrong message digest algorithms
catch (NoSuchAlgorithmException e) {
System.out.println("Exception thrown for incorrect algorithm: " + e);
}
return myString;
}
public static void main(String args[]) {
Hashing();
}
}
这个想法是将程序代码转换为 4 个类的变量。 我的问题是为什么我的类散列的 toString(boolean) 不起作用应该我覆盖，还是不应该？ 我不知道我的代码有什么问题，它说当前参数（不需要参数）不匹配（1 个参数布尔值） 我不能让它工作。 我想如果有人能给我一个线索我做错了什么，那么我可以解决它。 如果我覆盖系统说它不需要，因为 toString() 需要的参数。 感谢您的帮助，将不胜感激。 如果顺便有一些关于面向对象编程的书籍，任何人都可以建议我会非常感谢。 来自阿根廷的问候。
【问题讨论】：
标签： java refactoring procedural-programming