我无法在if语句中进行比较，在C编程中我使用“==”双等号来比较两个字符串......
如何使用getter方法将字符串与新字符串进行比较...我尝试使用双等号，但我被提示将其更改为：
if（entry [i] .getName（）。equals（EName））
这就是我的整个代码：
import javax.swing.JOptionPane;
import javax.swing.JTextArea;
public class AddressBook {
private AddressBookEntry entry[];
private int counter;
private String EName;
public static void main(String[] args) {
AddressBook a = new AddressBook();
a.entry = new AddressBookEntry[100];
int option = 0;
while (option != 5) {
String content = "Choose an Option\n\n"
+ "[1] Add an Entry\n"
+ "[2] Delete an Entry\n"
+ "[3] Update an Entry\n"
+ "[4] View all Entries\n"
+ "[5] View Specific Entry\n"
+ "[6] Exit";
option = Integer.parseInt(JOptionPane.showInputDialog(content));
switch (option) {
case 1:
a.addEntry();
break;
case 2:
break;
case 3:
a.editMenu();
break;
case 4:
a.viewAll();
break;
case 5:
break;
case 6:
System.exit(1);
break;
default:
JOptionPane.showMessageDialog(null, "Invalid Choice!");
}
}
}
public void addEntry() {
entry[counter] = new AddressBookEntry();
entry[counter].setName(JOptionPane.showInputDialog("Enter name: "));
entry[counter].setAdd(JOptionPane.showInputDialog("Enter add: "));
entry[counter].setPhoneNo(JOptionPane.showInputDialog("Enter Phone No.: "));
entry[counter].setEmail(JOptionPane.showInputDialog("Enter E-mail: "));
counter++;
}
public void viewAll() {
String addText= "";
for (int i = 0; i < counter; i++) {
addText = addText+(i+1)+ entry[i].getInfo()+ "\n";
}
JOptionPane.showMessageDialog(null, new JTextArea(addText));
}
public void editMenu() {
int option = 0;
while (option != 6) {
String content = "Choose an Option\n\n"
+ "[1] Edit Name\n"
+ "[2] Edit Address\n"
+ "[3] Edit Phone No.\n"
+ "[4] Edit E-mail address\n"
+ "[5] Back to Main Menu";
option = Integer.parseInt(JOptionPane.showInputDialog(content));
switch (option) {
case 1:
editName();
break;
case 2:
editAdd();
break;
case 3:
editPhoneNo();
break;
case 4:
editEmail();
break;
case 5:
return;
default:
JOptionPane.showMessageDialog(null, "Invalid Choice!");
}
}
}
public void editName() {
EName = JOptionPane.showInputDialog("Enter name to edit: ");
for (int i = 0; i < counter; i++) {
if (entry[i].getName().equals(EName)) {
//JOptionPane.showMessageDialog(null, "found");
entry[i].setName(JOptionPane.showInputDialog("Enter new name: "));
}else {
JOptionPane.showMessageDialog(null, "Entered Name not Found!");
}
}
}
public void editAdd() {
EName = JOptionPane.showInputDialog("Enter name to edit: ");
for (int i = 0; i < counter; i++) {
if (entry[i].getName().equals(EName)) {
//JOptionPane.showMessageDialog(null, "found");
entry[i].setAdd(JOptionPane.showInputDialog("Enter new Address: "));
}else {
JOptionPane.showMessageDialog(null, "Entered Name not Found!");
}
}
}
public void editPhoneNo() {
EName = JOptionPane.showInputDialog("Enter name to edit: ");
for (int i = 0; i < counter; i++) {
if (entry[i].getName().equals(EName)) {
//JOptionPane.showMessageDialog(null, "found");
entry[i].setPhoneNo(JOptionPane.showInputDialog("Enter new Phone No.: "));
}else {
JOptionPane.showMessageDialog(null, "Entered Name not Found!");
}
}
}
public void editEmail() {
EName = JOptionPane.showInputDialog("Enter name to edit: ");
for (int i = 0; i < counter; i++) {
if (entry[i].getName().equals(EName)) {
//JOptionPane.showMessageDialog(null, "found");
entry[i].setEmail(JOptionPane.showInputDialog("Enter new E-mail add: "));
}else {
JOptionPane.showMessageDialog(null, "Entered Name not Found!");
}
}
}
}
这是我的另一堂课：
public class AddressBookEntry {
private String name;
private String add;
private String phoneNo;
private String email;
private int entry;
public String getAdd() {
return add;
}
public String getEmail() {
return email;
}
public int getEntry() {
return entry;
}
public String getName() {
return name;
}
public String getPhoneNo() {
return phoneNo;
}
public void setAdd(String add) {
this.add = add;
}
public void setEmail(String email) {
this.email = email;
}
public void setEntry(int entry) {
this.entry = entry;
}
public void setName(String name) {
this.name = name;
}
public void setPhoneNo(String phoneNo) {
this.phoneNo = phoneNo;
}
public String getInfo() {
String Info = "NAME\tADDRESS\tPHONE NO.\tE-MAIL ADD\n"
+ name + "\t " + add + "\t " + phoneNo + "\t " + email + "\n";
return Info;
}
public String getInfo2() {
String content = "INFORMATION:\n\n"
+ "Name: " + name + "\n"
+ "Address: " + add + "\n"
+ "Tel. No: " + phoneNo + "\n"
+ "Email Add: " + email + "\n\n";
return content;
}
}
请原谅我的代码...我是java的新手....请帮助......
如果用户输入等于条目[i] .getName（）
，我想要遍历所有数组并编辑特定细节提前多多感谢...
答案 0 :(得分：3)
如果要比较字符串的表示形式而不是其对象标识，请使用equals()。
假设我们有：String s = "hello";
s == s
=> true // they are the *same* object
"hello" == new String("hello") // see comment below...
=> false // they are different objects representing the same string of text
"hello".equals("hello")
=> true
s.equals("hello")
=> true
答案 1 :(得分：1)
至少要理解3件事：
Java：==测试两个引用是否指向同一个对象，而equals测试两个对象是否具有相同的内容。因此，即使两个字符串具有相同的内容，==可能给出错误，而s1.equals（s2）将给出true。你可以在谷歌上找到关于此的负载。
C：在C中，你不应该使用==比较两个字符串。 C中的字符串通常是char *（或const char *），你应该将它们与strcmp进行比较（否则你会遇到与Java相同的问题）。
C ++：可以使用==。
比较std :: string的实例