在Java中创建具有唯一id的列表并对其进行操作
我想创建一个程序,创建一个如下所示的列表在Java中创建具有唯一id的列表并对其进行操作,java,arraylist,Java,Arraylist,我想创建一个程序,创建一个如下所示的列表 ID: 1 Name: Example Surname: Example email: example //New list ID: 2 Name: Example Surname: Example email: example public class Record{ private int id; private String name; private String Surname; private Strin
ID: 1
Name: Example
Surname: Example
email: example
//New list
ID: 2
Name: Example
Surname: Example
email: example
public class Record{
private int id;
private String name;
private String Surname;
private String email;
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getSurname() {
return Surname;
}
public void setSurname(String surname) {
Surname = surname;
}
public String getEmail() {
return email;
}
public void setEmail(String email) {
this.email = email;
}
}
然后,当我想更改某些内容(如Name:)时,我想按id更改它,因此只能在id为:2的列表中更改它您应该使用
HashMap
创建一个包含ID、名称、姓氏和电子邮件实例变量的类(让我们将其归类为YourClass)
然后创建一个HashMap
,其中键是标识符,值是YourClass
:
Map<Integer,YourClass> map = new HashMap<>();
map.put(objectOfYourClassWithID1.getID(),objectOfYourClassWithID1);
map.put(objectOfYourClassWithID2.getID(),objectOfYourClassWithID2);
if (map.containsKey(2)) {
map.get(2).setSomeProperty(newValue); // this will only change the object whose ID is 2
}
Map Map=newhashmap();
put(objectOfYourClassWithID1.getID(),objectOfYourClassWithID1);
put(objectOfYourClassWithID2.getID(),objectOfYourClassWithID2);
if(图2){
map.get(2).setSomeProperty(newValue);//这只会更改ID为2的对象
}
您应该使用HashMap
创建一个包含ID、名称、姓氏和电子邮件实例变量的类(让我们将其归类为YourClass)
然后创建一个HashMap
,其中键是标识符,值是YourClass
:
Map<Integer,YourClass> map = new HashMap<>();
map.put(objectOfYourClassWithID1.getID(),objectOfYourClassWithID1);
map.put(objectOfYourClassWithID2.getID(),objectOfYourClassWithID2);
if (map.containsKey(2)) {
map.get(2).setSomeProperty(newValue); // this will only change the object whose ID is 2
}
Map Map=newhashmap();
put(objectOfYourClassWithID1.getID(),objectOfYourClassWithID1);
put(objectOfYourClassWithID2.getID(),objectOfYourClassWithID2);
if(图2){
map.get(2).setSomeProperty(newValue);//这只会更改ID为2的对象
}
您可以创建这样的类
ID: 1
Name: Example
Surname: Example
email: example
//New list
ID: 2
Name: Example
Surname: Example
email: example
public class Record{
private int id;
private String name;
private String Surname;
private String email;
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getSurname() {
return Surname;
}
public void setSurname(String surname) {
Surname = surname;
}
public String getEmail() {
return email;
}
public void setEmail(String email) {
this.email = email;
}
}
然后像这样使用它:
Record record1 = new Record();
record1.setId(1);
record1.setName("example");
record1.setSurname("example");
record1.setEmail("example");
Record record2 = new Record();
record2.setId(2);
record2.setName("example");
record2.setSurname("example");
record2.setEmail("example");
Map<Integer,Record> recordMap = new HashMap<Integer, Record>();
recordMap.put(record1.getId(),record1);
recordMap.put(record2.getId(),record2);]
recordMap.get(2).getName();//example
recordMap.get(2).setName("ebi");
recordMap.get(2).getName();//ebi
Record record1=新记录();
记录1.setId(1);
记录1.setName(“示例”);
记录1.setSurname(“示例”);
记录1.setEmail(“示例”);
记录2=新记录();
记录2.setId(2);
记录2.setName(“示例”);
记录2.setSurname(“示例”);
记录2.setEmail(“示例”);
Map recordMap=newhashmap();
put(record1.getId(),record1);
recordMap.put(record2.getId(),record2);]
get(2.getName()//例子
recordMap.get(2.setName)(“ebi”);
get(2.getName()//息税前利润
您可以创建这样的类
ID: 1
Name: Example
Surname: Example
email: example
//New list
ID: 2
Name: Example
Surname: Example
email: example
public class Record{
private int id;
private String name;
private String Surname;
private String email;
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getSurname() {
return Surname;
}
public void setSurname(String surname) {
Surname = surname;
}
public String getEmail() {
return email;
}
public void setEmail(String email) {
this.email = email;
}
}
然后像这样使用它:
Record record1 = new Record();
record1.setId(1);
record1.setName("example");
record1.setSurname("example");
record1.setEmail("example");
Record record2 = new Record();
record2.setId(2);
record2.setName("example");
record2.setSurname("example");
record2.setEmail("example");
Map<Integer,Record> recordMap = new HashMap<Integer, Record>();
recordMap.put(record1.getId(),record1);
recordMap.put(record2.getId(),record2);]
recordMap.get(2).getName();//example
recordMap.get(2).setName("ebi");
recordMap.get(2).getName();//ebi
Record record1=新记录();
记录1.setId(1);
记录1.setName(“示例”);
记录1.setSurname(“示例”);
记录1.setEmail(“示例”);
记录2=新记录();
记录2.setId(2);
记录2.setName(“示例”);
记录2.setSurname(“示例”);
记录2.setEmail(“示例”);
Map recordMap=newhashmap();
put(record1.getId(),record1);
recordMap.put(record2.getId(),record2);]
get(2.getName()//例子
recordMap.get(2.setName)(“ebi”);
get(2.getName()//息税前利润
导入java.util.ArrayList;
导入java.util.List;
公共阶层人士{
私有int-id;
私有字符串名称;
私家姓;
私人字符串电子邮件;
公众人物(整数id、字符串名称、字符串姓氏、字符串电子邮件){
超级();
this.id=id;
this.name=名称;
姓=姓;
this.email=电子邮件;
}
公共int getId(){
返回id;
}
公共无效集合id(内部id){
this.id=id;
}
公共字符串getName(){
返回名称;
}
公共void集合名(字符串名){
this.name=名称;
}
公共字符串getNames(){
返回姓氏;
}
public void setSurname(字符串姓氏){
姓=姓;
}
公共字符串getEmail(){
回复邮件;
}
公用电子邮件(字符串电子邮件){
this.email=电子邮件;
}
公共静态void main(字符串[]args){
列表=新的ArrayList();
添加(新的人(1,“示例”、“示例”、“示例”));
添加(新的人(2,“示例”,“示例”,“示例”));
}
}
导入java.util.ArrayList;
导入java.util.List;
公共阶层人士{
私有int-id;
私有字符串名称;
私家姓;
私人字符串电子邮件;
公众人物(整数id、字符串名称、字符串姓氏、字符串电子邮件){
超级();
this.id=id;
this.name=名称;
姓=姓;
this.email=电子邮件;
}
公共int getId(){
返回id;
}
公共无效集合id(内部id){
this.id=id;
}
公共字符串getName(){
返回名称;
}
公共void集合名(字符串名){
this.name=名称;
}
公共字符串getNames(){
返回姓氏;
}
public void setSurname(字符串姓氏){
姓=姓;
}
公共字符串getEmail(){
回复邮件;
}
公用电子邮件(字符串电子邮件){
this.email=电子邮件;
}
公共静态void main(字符串[]args){
列表=新的ArrayList();
添加(新的人(1,“示例”、“示例”、“示例”));
添加(新的人(2,“示例”,“示例”,“示例”));
}
}
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