java – 查找和替换链接列表中的元素
发布时间：2020-12-15 02:32:20 所属栏目：Java 来源：网络整理
导读：我需要能够在链接列表中搜索某些唯一元素(用户名,密码,电子邮件),找到这些元素后,我需要转到列表中的下一个节点并开始一系列语句,允许用户更改配置文件信息.由于某种原因我的代码不起作用,我不知道如何解决它.任何帮助都会很棒！ GUI的外观 链接到帐户类：ht
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我需要能够在链接列表中搜索某些唯一元素(用户名,密码,电子邮件),找到这些元素后,我需要转到列表中的下一个节点并开始一系列语句,允许用户更改配置文件信息.由于某种原因我的代码不起作用,我不知道如何解决它.任何帮助都会很棒！
GUI的外观 链接到帐户类：http://pastebin.com/jnBrcnP1 因此,用户填写所需信息,如果他们想要更改“名称”或“性别”等个人资料信息,他们会更改信息,然后将旁边的ComboBox设置为“是”,然后单击“保存设置”按钮. 以下是链接列表的外观： tobi tobi123 tobi@hotmail.com tobi Mixed Breed Male 1-2 Virginia Walking peppy peppy123 peppy@hotmail.com peppy Chihuahua Male 5-6 Virginia Eating 这是我的按钮代码： private void jButtonP1ActionPerformed(java.awt.event.ActionEvent evt) {
//New Linked List created from file
LinkedList<Account> account = new LinkedList<Account>();
try
{
read(account,"doggydates.txt");
} catch (Exception e)
{
System.err.println(e.toString());
}
display(account);
//user information
String username = jTextFieldP3.getText();
String password = jPasswordFieldP1.getText();
String email = jTextFieldP4.getText();
String name = jTextFieldP1.getText();
String breed = (String) jComboBoxP4.getSelectedItem();
String gender = (String) jComboBoxP3.getSelectedItem();
String age = (String) jComboBoxP1.getSelectedItem();
String state = (String) jComboBoxP2.getSelectedItem();
String hobby = jTextFieldP2.getText();
//change combo boxes
String passchange = (String) jComboBoxP13.getSelectedItem();
String emailchange = (String) jComboBoxP14.getSelectedItem();
String namechange = (String) jComboBoxP6.getSelectedItem();
String breedchange = (String) jComboBoxP7.getSelectedItem();
String genderchange = (String) jComboBoxP8.getSelectedItem();
String agechange = (String) jComboBoxP9.getSelectedItem();
String statechange = (String) jComboBoxP10.getSelectedItem();
String hobbychange = (String) jComboBoxP11.getSelectedItem();
//cancel combo box
String accountcancel = (String) jComboBoxP5.getSelectedItem();
if(username.equals("") || password.equals("") || email.equals("")) // If password and username is empty > Do this >>>
{
jButtonP1.setEnabled(false);
jTextFieldP3.setText("");
jPasswordFieldP1.setText("");
jTextFieldP4.setText("");
jButtonP1.setEnabled(true);
this.setVisible(true);
}
else
{
ListIterator<Account> itr = account.listIterator();
while (itr.hasNext())
{
Account item = itr.next();
if(item.getUsername().equals(username) && item.getPassword().equals(password))
{
if(passchange.equals("Yes"))
{
for(Account acc : account){
if(acc.getUsername().equals(username)){
acc.goToNext();
acc.setDataAtCurrent(password);
}
}
}
if(emailchange.equals("Yes"))
{
for(Account acc : account){
if(acc.getUsername().equals(username)){
acc.goToNext();
acc.goToNext();
acc.setDataAtCurrent(email);
}
}
}
if(namechange.equals("Yes"))
{
for(Account acc : account){
if(acc.getUsername().equals(username)){
acc.goToNext();
acc.goToNext();
acc.goToNext();
acc.setDataAtCurrent(name);
}
}
}
if(breedchange.equals("Yes"))
{
for(Account acc : account){
if(acc.getUsername().equals(username)){
acc.goToNext();
acc.goToNext();
acc.goToNext();
acc.goToNext();
acc.setDataAtCurrent(breed);
}
}
}
if(genderchange.equals("Yes"))
{
for(Account acc : account){
if(acc.getUsername().equals(username)){
acc.goToNext();
acc.goToNext();
acc.goToNext();
acc.goToNext();
acc.goToNext();
acc.setDataAtCurrent(gender);
}
}
}
if(agechange.equals("Yes"))
{
for(Account acc : account){
if(acc.getUsername().equals(username)){
acc.goToNext();
acc.goToNext();
acc.goToNext();
acc.goToNext();
acc.goToNext();
acc.goToNext();
acc.setDataAtCurrent(age);
}
}
}
if(statechange.equals("Yes"))
{
for(Account acc : account){
if(acc.getUsername().equals(username)){
acc.goToNext();
acc.goToNext();
acc.goToNext();
acc.goToNext();
acc.goToNext();
acc.goToNext();
acc.goToNext();
acc.setDataAtCurrent(state);
}
}
}
if(hobbychange.equals("Yes"))
{
for(Account acc : account){
if(acc.getUsername().equals(username)){
acc.goToNext();
acc.goToNext();
acc.goToNext();
acc.goToNext();
acc.goToNext();
acc.goToNext();
acc.goToNext();
acc.goToNext();
acc.setDataAtCurrent(hobby);
}
}
}
if(accountcancel.equals("Yes"))
{
for(Account acc : account){
if(acc.getUsername().equals(username)){
acc.deleteCurrentNode();
acc.goToNext();
acc.deleteCurrentNode();
acc.goToNext();
acc.deleteCurrentNode();
acc.goToNext();
acc.deleteCurrentNode();
acc.goToNext();
acc.deleteCurrentNode();
acc.goToNext();
acc.deleteCurrentNode();
acc.goToNext();
acc.deleteCurrentNode();
acc.goToNext();
acc.deleteCurrentNode();
acc.goToNext();
acc.deleteCurrentNode();
}
}
}
}
}
String file_name = "doggydates.txt";
try {
FileWriter fstream = new FileWriter(file_name);
BufferedWriter out = new BufferedWriter(fstream);
ListIterator itr2 = account.listIterator();
while (itr2.hasNext()) {
Account element = (Account) itr2.next();
out.write("" + element);
out.newLine();
}
out.close();
System.out.println("File created successfully.");
} catch (Exception e) {
}
}
}
阅读方法： public static void read(LinkedList<Account> account,String inputFileName) throws java.io.IOException{
BufferedReader infile = new BufferedReader(new FileReader(inputFileName));
while(infile.ready())
{
String username = readLine(infile);
String password = readLine(infile);
String email = readLine(infile);
String name = readLine(infile);
String breed = readLine(infile);
String gender = readLine(infile);
String age = readLine(infile);
String state = readLine(infile);
String hobby = readLine(infile);
Account a = new Account(username,password,email,name,breed,gender,age,state,hobby);
account.add(a);
a.showList();
}
infile.close();
}
解决方法
查看代码,执行以下操作：
首先,LinkedList< Account> account = new LinkedList< Account>();这意味着每次用户单击“保存设置”按钮时都会创建列表. 二,ListIterator< Account> itr = account.listIterator();,但是帐号是一个空列表！因此,您无法将任何单个对象与任何人员数据进行比较. 最后,但并非最不重要的,阅读(帐户,“doggydates.txt”);在完成所有比较之后,我猜你正在读取文件数据并填写列表. 重新组织您的代码,然后重试. 更新： > Account类是您的实体.此类必须包含列表的数据.您可以像LinkedList的Node一样重用此类,指定指向其他Account对象引用的指针,无需使用ListNode实例. 您可以将设计更改为更简单的设计.我会给你2个样品供你设计： 表单1.将您的Acount类用作LinkedList节点. public class Account {
private Account next;
private Account previous;
private String username;
private String password;
private String email;
private String name;
private String breed;
private String gender;
private String age;
private String state;
private String hobby;
//constructor logic...
//getters and setters...
//toString method (for System.out.println)
}
public class AccountLinkedList {
private Account head;
private int size;
public AccountLinkedList() {
this.size = 0;
this.head = null;
}
public boolean insert(Account account) {
if (this.head == null) {
this.head = account;
} else {
Account current = head;
while (current.getNext() != null) {
current = current.getNext();
}
//maintain the LinkedList order
current.setNext(account);
account.setPrevious(current);
}
}
public Account findAccount(Account account) {
Account current = head;
while (current != null) {
if (current.equals(account) {
return current;
}
current = current.getNext();
}
return null;
}
//create the other methods to search,delete and traverse your list...
}
public class MyProgram {
public void jButtonP1ActionPerformed(java.awt.event.ActionEvent evt) {
Account account = new Account();
//set the account data,I'll just stick to username and
//password attributes
String username = jTextFieldP3.getText();
String password = jPasswordFieldP1.getText();
account.setUsername(username);
account.setPassword(password);
//perform the update
updateData();
}
public void updateData(Account account) {
AccountLinkedList accountList = new AccountLinkedList;
//loading data into our list
loadDataFromFile(accountList,"myFile.txt");
//perform the search operation
Account accountAux = accountList.findAccount(account);
//if the account is found,then update the accountAux data
if (accountAux != null) {
updateAccountData(accountAux,account);
} else {
accountList.insert(account);
}
//saving the modified data
saveDataToFile(accountList,"myFile.txt");
}
}
表单2.像实体一样使用Account类并使用Java LinkedList实现： //check that now you don't have the next and previous attributes
public class Account {
private String username;
private String password;
private String email;
private String name;
private String breed;
private String gender;
private String age;
private String state;
private String hobby;
//constructor logic...
//getters and setters...
//toString method (for System.out.println)
}
public class MyProgram {
public void jButtonP1ActionPerformed(java.awt.event.ActionEvent evt) {
Account account = new Account();
//set the account data,I'll just stick to username and
//password attributes
String username = jTextFieldP3.getText();
String password = jPasswordFieldP1.getText();
account.setUsername(username);
account.setPassword(password);
//perform the update
updateData();
}
public void updateData(Account account) {
LinkedList<Account> accountList = new LinkedList<Account>();
//loading data into our list
loadDataFromFile(accountList,"myFile.txt");
//perform the search operation
ListIterator<Account> li = accountList.listIterator();
Account accountAux = null;
while(li.hasNext()) {
accountAux = li.next();
//matching the account data outside with the current account
//of the list iterator,this is just a sample,you can change
//this logic
if (accountAux.equals(account) {
updateAccountData(accountAux,account);
break;
}
accountAux = null;
}
//in case the account was not fount in the LinkedList,add it.
if (accountAux == null)
accountList.add(account);
//saving the modified data
saveDataToFile(accountList,"myFile.txt");
}
}
IMO,我会坚持使用Form 2而不是Form1.希望它能帮到你. （编辑：李大同） 【声明】本站内容均来自网络，其相关言论仅代表作者个人观点，不代表本站立场。若无意侵犯到您的权利，请及时与联系站长删除相关内容! |