向JavaBean添加业务逻辑的良好设计
在下面的代码中，将ismatch放在Value对象/javabean中有意义吗 ? 什么是好的设计。顺便说一句，我尝试了compareTo、compare、hashSet等，方法是跟随其他关于堆栈溢出的帖子，但不知何故，我仍然无法从两个列表中删除DUP向JavaBean添加业务逻辑的良好设计,java,compare,software-design,compareto,Java,Compare,Software Design,Compareto,在下面的代码中，将ismatch放在Value对象/javabean中有意义吗 ? 什么是好的设计。顺便说一句，我尝试了compareTo、compare、hashSet等，方法是跟随其他关于堆栈溢出的帖子，但不知何故，我仍然无法从两个列表中删除DUP public class SessionAttributes { private static final Logger LOGGER = Logger .getLogger(SessionAttributes.class);
public class SessionAttributes {
private static final Logger LOGGER = Logger
.getLogger(SessionAttributes.class);
public SessionNotificationAttributes(String userName, String sessionState) {
this.userName = userName;
this.sessionState = sessionState;
}
String userName;
public String getUserName() {
return userName;
}
public void setUserName(String userName) {
this.userName = userName;
}
// .. getters/setters for sessionState
public static isMatched (List<SessionAttributes> list1,
List<SessionAttributes> list2) {
//.. custom logic here...
}
boolean b1 = removeDups.add(user11);
boolean b2 = removeDups.add(user12);
boolean b3 = removeDups.add(user13);
boolean b4 = removeDups.add(user3);
boolean b5 = removeDups.add(user4);
boolean b6 = removeDups.add(user5);
System.out.println(" Set--" + removeDups);
]我不会创建一个isMatched方法来比较两个SessionAttributes列表 我肯定会让SessionAttributes实现equals和hashCode。以相同的方式实现它们是至关重要的。如果要比较两个字符串是否相等，请使用这两个字符串计算哈希代码。如果您没有正确获得equals和hashCode，那么这一切都不起作用 如果您想将SessionAttributes放在SortedSet中，我也会让SessionAttributes实现Compariable 另外，我将使SessionAttributes不可变，因此没有setter，并将两个字符串元素声明为final。如果这样做，就可以将SessionAttribute添加到集合或映射中，而不必担心它们的值会发生变化。如果不使其不可变，则必须确保在将SessionAttributes值添加到列表或集合后不更改任何SessionAttributes值 我不会将它们放在列表中，而是将它们放在一个集合中，以确保在同一个SessionAttributes集合中没有重复项 如果要从其中一个集合中删除重复项，请对其使用集合的removeAll方法，将其传递给另一个SessionAttribute集合
作为一个旁注，SeStices状态看起来像一个具有有限数量可能值的变量，所以我会考虑为它定义一个枚举，而不是将它作为一个字符串。
我希望这有帮助 编辑： compareTo方法不起作用，因为如果相等，则返回0；如果不相等，则返回-1。 相比之下，它没有履行合同。请看它 以下是SSCCE，其中包含一些更改和注释。因为在equals中，比较相等忽略大小写，所以必须在hashCode方法中将字符串转换为所有大写或小写，以便与equals保持一致。为了保持一致性，您还必须在compareTo方法中使用compareIgnoreCase。 由于compareTo方法有效，现在您可以简单地使用树集对对象集合进行排序 我删除了您不再需要的方法，并尝试在代码中添加一些有用的注释package snippet;
import java.util.ArrayList;
import java.util.List;
import java.util.Set;
import java.util.TreeSet;
// You don't need to implement Comparator.
public class SessionAttributes implements Comparable<SessionAttributes> {
// You typically define member variables at the top of the class definition.
private final String userName;
private final String sessionState;
public SessionAttributes(String userName, String sessionState) {
// Throw a NullPointerException from the constructor if either of the Strings is null. This way, you know that
// if the object is constructed successfully, it is free of nulls.
if (userName == null) {
throw new NullPointerException("userName must not be null");
}
if (sessionState == null) {
throw new NullPointerException("sessionState must not be null");
}
/*
* String nasPort, String endpointProfile, String audiSessionId, String epsStatus, String securityGroup, String
* nasIp, String postureStatus, String postureTimestamp) {
*/
this.userName = userName;
this.sessionState = sessionState;
/*
* this.nasPort = nasPort; this.endpoinProfile = endpointProfile; this.auditSessionId = audiSessionId;
* this.epsStatus = epsStatus; this.securityGroup = securityGroup; this.nasIp = nasIp; this.postureStatus =
* postureStatus; this.postureTimestamp = postureTimestamp;
*/
}
public String getUserName() {
return userName;
}
public String getSessionState() {
return sessionState;
}
@Override
public int compareTo(SessionAttributes o) {
if (this == o) {
return 0;
}
// Null is considered less than any object.
if (o == null) {
return 1;
}
// Use compareToIgnoreCase since you used equalsIgnoreCase in equals.
int diff = userName.compareToIgnoreCase(o.userName);
if (diff != 0)
return diff;
diff = sessionState.compareToIgnoreCase(o.sessionState);
return diff;
}
// public int compareTo(SessionAttributes o) {
// // TODO Auto-generated method stub
// if (this.getUserName().equals(o.getUserName()) && this.getSessionState().equalsIgnoreCase(o.getSessionState())) {
// return 0;
// }
// return -1;
// }
public String toString() {
return "\n User Name : " + this.getUserName() + " Session State : " + getSessionState() + "\n";
}
// public boolean equals(SessionAttributes obj) {
//
// if (obj == null || !(obj instanceof SessionAttributes)) {
// return false;
// }
// System.out.println(" In equals==");
// boolean isSameUserName = obj.userName.equalsIgnoreCase(this.userName);
// boolean isSameState = obj.sessionState.equalsIgnoreCase(this.sessionState);
// return (isSameUserName && isSameState);
// }
public boolean equals(Object o) {
// See if o is the same object. If it is, return true.
if (o == this) {
return true;
}
// The instanceof check also checks for null. If o is null, instanceof will be false.
if (!(o instanceof SessionAttributes)) {
return false;
}
SessionAttributes that = (SessionAttributes) o;
return userName.equalsIgnoreCase(that.userName) && sessionState.equalsIgnoreCase(sessionState);
}
public int hashCode() {
System.out.println(" in hashcode ");
int hash = 1;
// Since in equals you are comparing for equality and ignoring case, you must convert the Strings to either
// lower
// or upper case when computing the hashCode so that it will always be consistent with equals.
hash = hash * 17 + this.getUserName().toUpperCase().hashCode();
hash = hash * 31 + this.getSessionState().toUpperCase().hashCode();
// hash = hash * 13 + this.getAuditSessionId().hashCode();
System.out.println(" hash=>" + hash);
return hash;
}
public static void main(String[] args) {
// sortSet();
// sortLists();
// expectedSessionList
List<SessionAttributes> expectedSessionList = new ArrayList<SessionAttributes>();
SessionAttributes user11 = new SessionAttributes("postureuser1", "STARTED"); //
// ,null,null,null,null,null,null,null,null);
SessionAttributes user12 = new SessionAttributes("postureuser1", "DISCONNECTED");
SessionAttributes user13 = new SessionAttributes("postureuser5", "STARTED");
expectedSessionList.add(user11);
expectedSessionList.add(user12);
expectedSessionList.add(user13);
System.out.println("expectedSessionList: " + expectedSessionList);
// actualSessionList
List<SessionAttributes> actualSessionList = new ArrayList<SessionAttributes>();
SessionAttributes user3 = new SessionAttributes("postureuser1", "STARTED");
// ,null,null,null,null,null,null,null,null);
SessionAttributes user4 = new SessionAttributes("postureuser1", "DISCONNECTED");
SessionAttributes user5 = new SessionAttributes("postureuser2", "DISCONNECTED");
// ,null,null,null,null,null,null,null,null);
actualSessionList.add(user3);
actualSessionList.add(user4);
actualSessionList.add(user5);
System.out.println("actualSessionList: " + actualSessionList);
// removeDups
// Use a TreeSet to sort it.
Set<SessionAttributes> removeDups = new TreeSet<SessionAttributes>();
boolean b1 = removeDups.add(user11);
boolean b2 = removeDups.add(user12);
boolean b3 = removeDups.add(user13);
boolean b4 = removeDups.add(user3);
boolean b5 = removeDups.add(user4);
boolean b6 = removeDups.add(user5);
System.out.println(" Set--" + removeDups);
actualSessionList.removeAll(expectedSessionList);
System.out.println("actualSessionList after removeAll: " + actualSessionList);
}
}
]谢谢您的评论。我实现了equals和hashCode。我没有粘贴整个代码。关于删除setter的好观点。我确实尝试过comparable，comparator，向集合中添加对象，HashSet，但不知何故它对我不起作用。我想要两个值匹配，比如userName=user1，sessionState=disconnected。不知何故，设置etc对我不起作用。这里有与此相关的帖子，所以我遵循了这些帖子，但没有起作用。不确定是不是由getter/setter引起的。让我尝试删除setter/getter并尝试Set/removaAll方法。如果您仍然无法使其工作，请使用一个简短、自包含、可编译的示例更新您的问题。实际上，上面的代码是针对SSCCE的。让我获取完整的代码，您可以建议可能缺少的内容。我放弃了Comparator，用蛮力的方式迭代会话bean列表，用EqualsThank找到匹配项谢谢，David。你测试过了吗？看起来和我贴的很像。谢谢你花时间在这上面。谢谢。嗨，是的，我试过了。它起作用了。不客气。表示感谢的方式是批准回答。如果您觉得我对您的问题的回答令您满意，请批准。谢谢
boolean b1 = removeDups.add(user11);
boolean b2 = removeDups.add(user12);
boolean b3 = removeDups.add(user13);
boolean b4 = removeDups.add(user3);
boolean b5 = removeDups.add(user4);
boolean b6 = removeDups.add(user5);
System.out.println(" Set--" + removeDups);
package snippet;
import java.util.ArrayList;
import java.util.List;
import java.util.Set;
import java.util.TreeSet;
// You don't need to implement Comparator.
public class SessionAttributes implements Comparable<SessionAttributes> {
// You typically define member variables at the top of the class definition.
private final String userName;
private final String sessionState;
public SessionAttributes(String userName, String sessionState) {
// Throw a NullPointerException from the constructor if either of the Strings is null. This way, you know that
// if the object is constructed successfully, it is free of nulls.
if (userName == null) {
throw new NullPointerException("userName must not be null");
}
if (sessionState == null) {
throw new NullPointerException("sessionState must not be null");
}
/*
* String nasPort, String endpointProfile, String audiSessionId, String epsStatus, String securityGroup, String
* nasIp, String postureStatus, String postureTimestamp) {
*/
this.userName = userName;
this.sessionState = sessionState;
/*
* this.nasPort = nasPort; this.endpoinProfile = endpointProfile; this.auditSessionId = audiSessionId;
* this.epsStatus = epsStatus; this.securityGroup = securityGroup; this.nasIp = nasIp; this.postureStatus =
* postureStatus; this.postureTimestamp = postureTimestamp;
*/
}
public String getUserName() {
return userName;
}
public String getSessionState() {
return sessionState;
}
@Override
public int compareTo(SessionAttributes o) {
if (this == o) {
return 0;
}
// Null is considered less than any object.
if (o == null) {
return 1;
}
// Use compareToIgnoreCase since you used equalsIgnoreCase in equals.
int diff = userName.compareToIgnoreCase(o.userName);
if (diff != 0)
return diff;
diff = sessionState.compareToIgnoreCase(o.sessionState);
return diff;
}
// public int compareTo(SessionAttributes o) {
// // TODO Auto-generated method stub
// if (this.getUserName().equals(o.getUserName()) && this.getSessionState().equalsIgnoreCase(o.getSessionState())) {
// return 0;
// }
// return -1;
// }
public String toString() {
return "\n User Name : " + this.getUserName() + " Session State : " + getSessionState() + "\n";
}
// public boolean equals(SessionAttributes obj) {
//
// if (obj == null || !(obj instanceof SessionAttributes)) {
// return false;
// }
// System.out.println(" In equals==");
// boolean isSameUserName = obj.userName.equalsIgnoreCase(this.userName);
// boolean isSameState = obj.sessionState.equalsIgnoreCase(this.sessionState);
// return (isSameUserName && isSameState);
// }
public boolean equals(Object o) {
// See if o is the same object. If it is, return true.
if (o == this) {
return true;
}
// The instanceof check also checks for null. If o is null, instanceof will be false.
if (!(o instanceof SessionAttributes)) {
return false;
}
SessionAttributes that = (SessionAttributes) o;
return userName.equalsIgnoreCase(that.userName) && sessionState.equalsIgnoreCase(sessionState);
}
public int hashCode() {
System.out.println(" in hashcode ");
int hash = 1;
// Since in equals you are comparing for equality and ignoring case, you must convert the Strings to either
// lower
// or upper case when computing the hashCode so that it will always be consistent with equals.
hash = hash * 17 + this.getUserName().toUpperCase().hashCode();
hash = hash * 31 + this.getSessionState().toUpperCase().hashCode();
// hash = hash * 13 + this.getAuditSessionId().hashCode();
System.out.println(" hash=>" + hash);
return hash;
}
public static void main(String[] args) {
// sortSet();
// sortLists();
// expectedSessionList
List<SessionAttributes> expectedSessionList = new ArrayList<SessionAttributes>();
SessionAttributes user11 = new SessionAttributes("postureuser1", "STARTED"); //
// ,null,null,null,null,null,null,null,null);
SessionAttributes user12 = new SessionAttributes("postureuser1", "DISCONNECTED");
SessionAttributes user13 = new SessionAttributes("postureuser5", "STARTED");
expectedSessionList.add(user11);
expectedSessionList.add(user12);
expectedSessionList.add(user13);
System.out.println("expectedSessionList: " + expectedSessionList);
// actualSessionList
List<SessionAttributes> actualSessionList = new ArrayList<SessionAttributes>();
SessionAttributes user3 = new SessionAttributes("postureuser1", "STARTED");
// ,null,null,null,null,null,null,null,null);
SessionAttributes user4 = new SessionAttributes("postureuser1", "DISCONNECTED");
SessionAttributes user5 = new SessionAttributes("postureuser2", "DISCONNECTED");
// ,null,null,null,null,null,null,null,null);
actualSessionList.add(user3);
actualSessionList.add(user4);
actualSessionList.add(user5);
System.out.println("actualSessionList: " + actualSessionList);
// removeDups
// Use a TreeSet to sort it.
Set<SessionAttributes> removeDups = new TreeSet<SessionAttributes>();
boolean b1 = removeDups.add(user11);
boolean b2 = removeDups.add(user12);
boolean b3 = removeDups.add(user13);
boolean b4 = removeDups.add(user3);
boolean b5 = removeDups.add(user4);
boolean b6 = removeDups.add(user5);
System.out.println(" Set--" + removeDups);
actualSessionList.removeAll(expectedSessionList);
System.out.println("actualSessionList after removeAll: " + actualSessionList);
}
}