Hi,I encountered some problems when i am learning the treeSet. The following is the code. Could anyone help me please? The error messages are "TreetSet cannot be resolved or is not a type". I couldn't tell the problems. Thank you.
======================================
import java.util.HashMap;
import java.util.Iterator;
import java.util.Set;
import java.util.TreeSet;public class Demo {
public static void main(String[] args){
HashMap hashMap=new HashMap();
hashMap.put("Schmidt","+49 6227 48597");
hashMap.put("Mayer","+49 6221 1808");
hashMap.put("Schmidt","+49 40 364850");
hashMap.put("Treusch","+49 89 98965456");
Set keys= hashMap.keySet();
Iterator iter=keys.iterator();
while (iter.hasNext()){
String key=(String) iter.next();
String value=(String) hashMap.get(key);
System.out.println("key: "+key+"\tvalue: "+value);
}
TreetSet treetSet=new TreetSet();
treetSet.add(new Customer("Schmidt",48597));
treetSet.add(new Customer("Mayer",180));
treetSet.add(new Customer("Schmidt",3648));
Iterator iter2=treetSet.iterator();
while (iter2.hasNext()){
Customer customer=(Customer)iter2.next();
System.out.println(customer.getName());
}
}
public class Customer implements Comparable{
private String name;
private int id;
public Customer(String name, int id){
this.name=name;
this.id=id;
}
public int getId(){
return id;
}
public String getName(){
return name;
}
public int compareTo(Object otherCustomer){
return this.id=((Customer)otherCustomer).getId();
}
}
}
======================================
import java.util.HashMap;
import java.util.Iterator;
import java.util.Set;
import java.util.TreeSet;public class Demo {
public static void main(String[] args){
HashMap hashMap=new HashMap();
hashMap.put("Schmidt","+49 6227 48597");
hashMap.put("Mayer","+49 6221 1808");
hashMap.put("Schmidt","+49 40 364850");
hashMap.put("Treusch","+49 89 98965456");
Set keys= hashMap.keySet();
Iterator iter=keys.iterator();
while (iter.hasNext()){
String key=(String) iter.next();
String value=(String) hashMap.get(key);
System.out.println("key: "+key+"\tvalue: "+value);
}
TreetSet treetSet=new TreetSet();
treetSet.add(new Customer("Schmidt",48597));
treetSet.add(new Customer("Mayer",180));
treetSet.add(new Customer("Schmidt",3648));
Iterator iter2=treetSet.iterator();
while (iter2.hasNext()){
Customer customer=(Customer)iter2.next();
System.out.println(customer.getName());
}
}
public class Customer implements Comparable{
private String name;
private int id;
public Customer(String name, int id){
this.name=name;
this.id=id;
}
public int getId(){
return id;
}
public String getName(){
return name;
}
public int compareTo(Object otherCustomer){
return this.id=((Customer)otherCustomer).getId();
}
}
}
我发觉了一个问题,好多人还在用手写JAVA代码,没有用过IDE
import java.util.HashMap;
import java.util.Iterator;
import java.util.Set;
import java.util.TreeSet;public class Demo {
public static void main(String[] args){
HashMap hashMap=new HashMap();
hashMap.put("Schmidt","+49 6227 48597");
hashMap.put("Mayer","+49 6221 1808");
hashMap.put("Schmidt","+49 40 364850");
hashMap.put("Treusch","+49 89 98965456");
Set keys= hashMap.keySet();
Iterator iter=keys.iterator();
while (iter.hasNext()){
String key=(String) iter.next();
String value=(String) hashMap.get(key);
System.out.println("key: "+key+"\tvalue: "+value);
}
TreeSet treeSet=new TreeSet();
treeSet.add(new Customer("Schmidt",48597));
treeSet.add(new Customer("Mayer",180));
treeSet.add(new Customer("Schmidt",3648));
Iterator iter2=treeSet.iterator();
while (iter2.hasNext()){
Customer customer=(Customer)iter2.next();
System.out.println(customer.getName());
}
}
public class Customer implements Comparable{
private String name;
private int id;
public Customer(String name, int id){
this.name=name;
this.id=id;
}
public int getId(){
return id;
}
public String getName(){
return name;
}
public int compareTo(Object otherCustomer){
return this.id=((Customer)otherCustomer).getId();
}
}
}The error message is "No enclosing instance of type Demo is accessible. Must qualify the allocation with an enclosing instance of type Demo (e.g. x.new A() where x is an instance of Demo)."
import java.util.Iterator;
import java.util.Set;
import java.util.TreeSet; public class Demo {
public static void main(String[] args){
HashMap hashMap=new HashMap(); hashMap.put("Schmidt","+49 6227 48597");
hashMap.put("Mayer","+49 6221 1808");
hashMap.put("Schmidt","+49 40 364850");
hashMap.put("Treusch","+49 89 98965456"); Set keys= hashMap.keySet();
Iterator iter=keys.iterator(); while (iter.hasNext()){
String key=(String) iter.next();
String value=(String) hashMap.get(key);
System.out.println("key: "+key+"\tvalue: "+value);
} TreeSet treeSet=new TreeSet(); treeSet.add(new Customer("Schmidt",48597));
treeSet.add(new Customer("Mayer",180));
treeSet.add(new Customer("Schmidt",3648)); Iterator iter2=treeSet.iterator();
while (iter2.hasNext()){
Customer customer=(Customer)iter2.next();
System.out.println(customer.getName());
}
}
} class Customer implements Comparable{
private String name;
private int id; public Customer(String name, int id){
this.name=name;
this.id=id;
} public int getId(){
return id;
} public String getName(){
return name;
} public int compareTo(Object otherCustomer){
return this.id=((Customer)otherCustomer).getId();
}
}
import java.util.HashMap;
import java.util.Iterator;
import java.util.Set;
import java.util.TreeSet; public class Demo {
public static void main(String[] args){
HashMap hashMap=new HashMap(); hashMap.put("Schmidt","+49 6227 48597");
hashMap.put("Mayer","+49 6221 1808");
hashMap.put("Schmidt","+49 40 364850");
hashMap.put("Treusch","+49 89 98965456"); Set keys= hashMap.keySet();
Iterator iter=keys.iterator(); while (iter.hasNext()){
String key=(String) iter.next();
String value=(String) hashMap.get(key);
System.out.println("key: "+key+"\tvalue: "+value);
} TreeSet treeSet=new TreeSet(); treeSet.add(new Demo().new Customer("Schmidt",48597));
treeSet.add(new Demo().new Customer("Mayer",180));
treeSet.add(new Demo().new Customer("Schmidt",3648)); Iterator iter2=treeSet.iterator();
while (iter2.hasNext()){
Customer customer=(Customer)iter2.next();
System.out.println(customer.getName());
}
} class Customer implements Comparable{
private String name;
private int id; public Customer(String name, int id){
this.name=name;
this.id=id;
} public int getId(){
return id;
} public String getName(){
return name;
} public int compareTo(Object otherCustomer){
return this.id=((Customer)otherCustomer).getId();
}
}
}
* To change this template, choose Tools | Templates
* and open the template in the editor.
*/
package exp1;/**
*
* @author 波
*/
import java.util.HashMap;
import java.util.Iterator;
import java.util.Set;
import java.util.TreeSet;public class Demo { public static void main(String[] args) {
HashMap hashMap = new HashMap(); hashMap.put("Schmidt", "+49 6227 48597");
hashMap.put("Mayer", "+49 6221 1808");
hashMap.put("Schmidt", "+49 40 364850");
hashMap.put("Treusch", "+49 89 98965456"); Set keys = hashMap.keySet();
Iterator iter = keys.iterator(); while (iter.hasNext()) {
String key = (String) iter.next();
String value = (String) hashMap.get(key);
System.out.println("key: " + key + "\tvalue: " + value);
} TreeSet tree = new TreeSet(); tree.add(new Demo().new Customer("Schmidt", 48597));
tree.add(new Demo().new Customer("Mayer", 180));
tree.add(new Demo().new Customer("Schmidt", 3648)); Iterator iter2 = tree.iterator();
while (iter2.hasNext()) {
Customer customer = (Customer) iter2.next();
System.out.println(customer.getName());
}
} public class Customer implements Comparable { private String name;
private int id; public Customer(String name, int id) {
this.name = name;
this.id = id;
} public int getId() {
return id;
} public String getName() {
return name;
} public int compareTo(Object otherCustomer) {
return this.id = ((Customer) otherCustomer).getId();
}
}
}
这个的参数传递的也不对