新手疑问。关于封装的思想动态数组arraylist

import java.util.ArrayList;
public class StrDemo {

public static void main(String[] args) {
ArrayList ary=new ArrayList();
Str st=new Str("Dacid Clarke","10 Doening Street","LondnState : London",
"United Kingdom","110022");
Str st1=new Str("John Lenon","12 Park Avenue","CliforniaState : CaliFornia",
"USA","210033");
Str st2=new Str("Stefii Graff","14 Mape Lane","LondonState : Sydney","Australia","412033");
ary.add(st.getArry());
for(int i=0;i<=5;i++){
System.out.println(ary.get(i));
}
}
}import java.util.ArrayList;
public class Str {
private ArrayList arry=new ArrayList();
private String name;
private String Street;
private String City;
private String Country;
private String Picde;

public Str(String str,String st2,String st3,String st4,String st5){
name=str;
Street=st2;
City=st3;
Country=st4;
Picde=st5;
}
public void setArry(){
arry.clear();
arry.add(name);
arry.add(Street);
arry.add(City);
arry.add(Country);
arry.add(Picde);
}
public ArrayList getArry(){
return arry;
}
public void print(){
for(int i=0;i<5;i++){
System.out.println(arry.get(i));
}
}
} 这代码报错，好像是出在size和index上。。
请高手帮我改一下那里错了，用封装的话是怎么写。。我都搞不清我弄的是不是封装
原题目是
编写一个程序，使用ArrayList存储客户的邮件地址。地址中应该包含姓名，街道，市（县）,省，国家，和代码，然后显示ArrayList中的内容，此程序的输出结果该显示如下:
客户的邮件地址[Name: Dacid Clarke
Street :10 Doening Street
City : LondonState : London
Country : United Kingdom
Picde : 110022Name: John Lenon
Street :12 Park Avenue
City : CliforniaState : California
Country : USA
Picde : 210033Name:Stefii Graff
Street : 14 Mape Lane
City : LondonState : Sydney
Country : Australia
Picde : 412033]

解决方案 »

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首先你应该将用户的信息归为一类  UserInfo
然后你的arrayList中存的是UserInfo的对象
能改一下代码吗封装的思想我也不太理解  还有arraylist的大小索引那些很迷糊
public static void main(String[] args) {
        ArrayList<Str> ary=new ArrayList<Str>();
        Str st=new Str("Dacid Clarke","10 Doening Street","LondnState : London",
                "United Kingdom","110022");
        Str st1=new Str("John Lenon","12 Park Avenue","CliforniaState : CaliFornia",
                "USA","210033");
        Str st2=new Str("Stefii Graff","14 Mape Lane","LondonState : Sydney","Australia","412033");
        ary.add(st.getArry());
                for(int i=0;i<=5;i++){
               Str str = ary.get(i);
            System.out.println(str.getName());
        }
    }
}
对应的str类定义的成员变量加上get set方法，用泛型链表
UserInfo.java
package com.hundsun.zhoujl;/**
* @author zhoujl
* 2011/12/27 14:37:27
*/
public class UserInfo { private String name;
private String street;
private String city;
private String country;
private String picde;

/**
* @param name
* @param street
* @param city
* @param country
* @param picde
*/
public UserInfo(String name, String street, String city, String country,
String picde) {
super();
this.name = name;
this.street = street;
this.city = city;
this.country = country;
this.picde = picde;
}

public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getStreet() {
return street;
}
public void setStreet(String street) {
this.street = street;
}
public String getCity() {
return city;
}
public void setCity(String city) {
this.city = city;
}
public String getCountry() {
return country;
}
public void setCountry(String country) {
this.country = country;
}
public String getPicde() {
return picde;
}
public void setPicde(String picde) {
this.picde = picde;
} @Override
public String toString() {
return "Name:"+name+"\n"+"Street:" + street+"\n"+"City:"+city+"\n"
+"Country:"+country+"\n"+"Picde:"+picde;
}

}
UserInfoDB.java
package com.hundsun.zhoujl;import java.util.ArrayList;
import java.util.List;/**
* @author zhoujl
* 2011/12/27 14:47:59
*/
public class UserInfoDB { private List<UserInfo> userInfoList = null;

public UserInfoDB() {
userInfoList = new ArrayList<UserInfo>();
}

public void addUserInfo(UserInfo userInfo) {
userInfoList.add(userInfo);
}

public void showAllUserInfo() {
System.out.print("[");
for(int i=0;i<userInfoList.size();i++) {
System.out.print(userInfoList.get(i));
if(i != userInfoList.size()-1) {
System.out.println("\n");
}
}
System.out.print("]");

}

public void clearDB() {
userInfoList.clear();
}
}
Main.java
package com.hundsun.zhoujl;import java.util.ArrayList;
import java.util.List;/**
* @author zhoujl
* 2011/12/27 14:41:10
*/
public class Main {
public static void main(String[] args) {
UserInfoDB db = new UserInfoDB();
UserInfo userInfo1 = new UserInfo("Dacid Clarke","10 Doening Street","LondnState : London",
                "United Kingdom","110022");
UserInfo userInfo2 = new UserInfo("John Lenon","12 Park Avenue","CliforniaState : CaliFornia",
                "USA","210033");
UserInfo userInfo3 = new UserInfo("Stefii Graff","14 Mape Lane","LondonState : Sydney","Australia","412033");
db.addUserInfo(userInfo1);
db.addUserInfo(userInfo2);
db.addUserInfo(userInfo3);
db.showAllUserInfo();
db.clearDB();
}
}这玩意很灵活的看你的程序该怎么用
首先用户信息肯定封装成一个类，例如User ，然后ArrayList里面存放User根据你的代码修改的
import java.util.ArrayList;
class Str {
    private String name;
    private String Street;
    private String City;
    private String Country;
    private String Picde;

    public Str(String str,String st2,String st3,String st4,String st5){
        name=str;
        Street=st2;
        City=st3;
        Country=st4;
        Picde=st5;
    }

public String toString(){
StringBuffer sb = new StringBuffer();
sb.append("name :").append(name).append("\n");
sb.append("Street :").append(Street).append("\n");
sb.append("City :").append(City).append("\n");
sb.append("Country :").append(Country).append("\n");
sb.append("Picde :").append(Picde).append("\n");

return sb.toString(); }
}
public class StrDemo {

    public static void main(String[] args) {
        ArrayList<Str> ary=new ArrayList<Str>();
        Str st=new Str("Dacid Clarke","10 Doening Street","LondnState : London",
                "United Kingdom","110022");
        Str st1=new Str("John Lenon","12 Park Avenue","CliforniaState : CaliFornia",
                "USA","210033");
        Str st2=new Str("Stefii Graff","14 Mape Lane","LondonState : Sydney","Australia","412033");


ary.add(st);
ary.add(st1);
ary.add(st2);
                for(int i=0;i<ary.size();i++){
            System.out.println(ary.get(i));
        }
    }
}
UserInfo.java
package com.hundsun.zhoujl;/**
* @author zhoujl
* 2011/12/27 14:37:27
*/
public class UserInfo { private String name;
private String street;
private String city;
private String country;
private String picde;

/**
* @param name
* @param street
* @param city
* @param country
* @param picde
*/
public UserInfo(String name, String street, String city, String country,
String picde) {
super();
this.name = name;
this.street = street;
this.city = city;
this.country = country;
this.picde = picde;
}

public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getStreet() {
return street;
}
public void setStreet(String street) {
this.street = street;
}
public String getCity() {
return city;
}
public void setCity(String city) {
this.city = city;
}
public String getCountry() {
return country;
}
public void setCountry(String country) {
this.country = country;
}
public String getPicde() {
return picde;
}
public void setPicde(String picde) {
this.picde = picde;
} @Override
public String toString() {
return "Name:"+name+"\n"+"Street:" + street+"\n"+"City:"+city+"\n"
+"Country:"+country+"\n"+"Picde:"+picde;
}

}
UserInfoDB.java
package com.hundsun.zhoujl;import java.util.ArrayList;
import java.util.List;/**
* @author zhoujl
* 2011/12/27 14:47:59
*/
public class UserInfoDB { private List<UserInfo> userInfoList = null;

public UserInfoDB() {
userInfoList = new ArrayList<UserInfo>();
}

public void addUserInfo(UserInfo userInfo) {
userInfoList.add(userInfo);
}

public void showAllUserInfo() {
System.out.print("[");
for(int i=0;i<userInfoList.size();i++) {
System.out.print(userInfoList.get(i));
if(i != userInfoList.size()-1) {
System.out.println("\n");
}
}
System.out.print("]");

}

public void clearDB() {
userInfoList.clear();
}
}Mian.java
package com.hundsun.zhoujl;
/**
* @author zhoujl
* 2011/12/27 14:41:10
*/
public class Main {
public static void main(String[] args) {
UserInfoDB db = new UserInfoDB();
UserInfo userInfo1 = new UserInfo("Dacid Clarke","10 Doening Street","LondnState : London",
                "United Kingdom","110022");
UserInfo userInfo2 = new UserInfo("John Lenon","12 Park Avenue","CliforniaState : CaliFornia",
                "USA","210033");
UserInfo userInfo3 = new UserInfo("Stefii Graff","14 Mape Lane","LondonState : Sydney","Australia","412033");
db.addUserInfo(userInfo1);
db.addUserInfo(userInfo2);
db.addUserInfo(userInfo3);
db.showAllUserInfo();
db.clearDB();
}
}
UserInfo
package com.hundsun.zhoujl;/**
* @author zhoujl
* 2011/12/27 14:37:27
*/
public class UserInfo { private String name;
private String street;
private String city;
private String country;
private String picde;

/**
* @param name
* @param street
* @param city
* @param country
* @param picde
*/
public UserInfo(String name, String street, String city, String country,
String picde) {
super();
this.name = name;
this.street = street;
this.city = city;
this.country = country;
this.picde = picde;
}

public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getStreet() {
return street;
}
public void setStreet(String street) {
this.street = street;
}
public String getCity() {
return city;
}
public void setCity(String city) {
this.city = city;
}
public String getCountry() {
return country;
}
public void setCountry(String country) {
this.country = country;
}
public String getPicde() {
return picde;
}
public void setPicde(String picde) {
this.picde = picde;
} @Override
public String toString() {
return "Name:"+name+"\n"+"Street:" + street+"\n"+"City:"+city+"\n"
+"Country:"+country+"\n"+"Picde:"+picde;
}

}
UserInfoDB
package com.hundsun.zhoujl;import java.util.ArrayList;
import java.util.List;/**
* @author zhoujl
* 2011/12/27 14:47:59
*/
public class UserInfoDB { private List<UserInfo> userInfoList = null;

public UserInfoDB() {
userInfoList = new ArrayList<UserInfo>();
}

public void addUserInfo(UserInfo userInfo) {
userInfoList.add(userInfo);
}

public void showAllUserInfo() {
System.out.print("[");
for(int i=0;i<userInfoList.size();i++) {
System.out.print(userInfoList.get(i));
if(i != userInfoList.size()-1) {
System.out.println("\n");
}
}
System.out.print("]");

}

public void clearDB() {
userInfoList.clear();
}
}
Main.java
package com.hundsun.zhoujl;
/**
* @author zhoujl
* 2011/12/27 14:41:10
*/
public class Main {
public static void main(String[] args) {
UserInfoDB db = new UserInfoDB();
UserInfo userInfo1 = new UserInfo("Dacid Clarke","10 Doening Street","LondnState : London",
                "United Kingdom","110022");
UserInfo userInfo2 = new UserInfo("John Lenon","12 Park Avenue","CliforniaState : CaliFornia",
                "USA","210033");
UserInfo userInfo3 = new UserInfo("Stefii Graff","14 Mape Lane","LondonState : Sydney","Australia","412033");
db.addUserInfo(userInfo1);
db.addUserInfo(userInfo2);
db.addUserInfo(userInfo3);
db.showAllUserInfo();
db.clearDB();
}
}
7楼封装在一个类就是用的toString方法吗然后ArrayList<Str> ary=new ArrayList<Str>();这个语句 <>这个我还是第一次看到能不能解释下
7楼封装在一个类就是用的toString方法吗然后ArrayList<Str> ary=new ArrayList<Str>();这个语句 <>这个我还是第一次看到能不能解释下
ary.add（new Str("Dacid Clarke","10 Doening Street","LondnState : London",
                "United Kingdom","110022")）；
每次添加一个对象
ArrayList<Str> ary=new ArrayList<Str>();这一句是用范型，指出：在集合ArrayList里只能添加Str类型的对象，如果add进去不是Str类型的，就会报错！可以看JDK文档