新手学J2SE，遇到一个集合问题，搞不懂代码什么意思

0 0

新手学J2SE，遇到一个集合问题，搞不懂代码什么意思5

主要有3个类：
public class CompareTable {

public static List list = new ArrayList();
static{
String[]s1 = {"赵","z"};
String[]s2 = {"钱","q"};
String[]s3 = {"孙","s"};
String[]s4 = {"李","l"};
String[]s5 = {"周","z"};
String[]s6 = {"吴","w"};
String[]s7 = {"郑","z"};
String[]s8 = {"王","w"};
list.add(s1);
list.add(s2);
list.add(s3);
list.add(s4);
list.add(s5);
list.add(s6);
list.add(s7);
list.add(s8);

}
}

package Account;

import Object.Person;

public class Account implements Comparable{
private String name;
private int age;
private int money;

public Account(String name,int age,int money) {
this.name = name;
this.age = age;
this.money = money;
}

public String getName() {
return name;
}

public void setName(String name) {
this.name = name;
}

public int getAge() {
return age;
}

public void setAge(int age) {
this.age = age;
}

public int getMoney() {
return money;
}

public void setMoney(int money) {
this.money = money;
}

public String toString() {
return name+" "+age+" "+money;
}
public boolean eqsuals(Object otherObject) {
//检查otherObject同this是不是同一个对象
if(this ==otherObject) return true;
//检查otherObject是否为null
if(otherObject ==null) return false;
//检查otherObject是不是某类的实例
if(!(otherObject instanceof Person)) return false;
//强制类型转换，执行按照业务要比较的2个对象的属性
Account other = (Account)otherObject;
if(age == other.age && name == other.name && money == other.money) return true;
else
return false;
}
public int hashCode() {
return this.name.hashCode()+this.age+this.money;
}

@Override
public int compareTo(Object object) {
Account account = (Account)object;
String firstName = this.name.substring(0,1);
String otherName = account.name.substring(0,1);
//System.out.println(firstName);
System.out.println(otherName);
char fc = 0;
char oc =0;
for(int i=0;i<CompareTable.list.size();i++) {
String s[] = (String[]) CompareTable.list.get(i);
if(s[0].equals(firstName)) {
fc = s[1].toCharArray()[0];
break;
}
if(s[0].equals(otherName)) {
oc = s[1].toCharArray()[0];
break;
}
}
if(fc>oc)
return -1;
if(fc<oc) return 1;
else
return 0;
}

/*public int compareTo(Object object) {
Account account = (Account)object;
if(age<account.age) return 1;
if(age>account.age) return -1;
else
return 0;
}*/

}
package Account;

import java.util.Set;
import java.util.TreeSet;

public class TreeSetTestMain {
public static void main(String[] args) {
Set set = new TreeSet();
//set.add("1");
//set.add("3");
//set.add("2");
//for (Object o : set) {
// System.out.println(o);
//}
set.add(new Account("赵宁",21,1000));
set.add(new Account("吴宁",1,4000));
set.add(new Account("李宁",2,3000));
set.add(new Account("王宁",3,2000));
set.add(new Account("钱宁",24,6000));
for (Object o : set) {
System.out.println(o);
}

}

}

以及那个比较方法具体是怎么实现的
我最搞不懂的是firstName和otherName输出来的结果。

J2SE 集合

2012年10月24日 13:05

luozhining
26
0 0 3

1个答案按时间排序按投票排序

0 0

采纳的答案

TreeSet对象每次add的时候，都会把要add的对象和目前set里的（部分）对象比较，以便让新增的元素放在合适的位置上。但是和哪个先比较，比较几次？我们定不了，只要JVM认为新加入的元素到了合适的位置，就停止比较，所以，firstName和otherName输出来的结果基本没有什么意义，也就无所谓看懂看不懂了。

如果你偏偏想看懂，对你的代码略加修改，你仔细品味其中奥妙吧

package Account;

import java.util.Set;
import java.util.TreeSet;


public class TreeSetTestMain {
public static void main(String[] args) {
Set set = new TreeSet();
//set.add("1");
//set.add("3");
//set.add("2");
//for (Object o : set) {
// System.out.println(o);
//}
System.out.println(" add 赵宁 开始");
set.add(new Account("赵宁",21,1000));
System.out.println(" add 赵宁 结束");
System.out.println();
System.out.println();

System.out.println(" add 吴宁 开始");
set.add(new Account("吴宁",1,4000));
System.out.println(" add 吴宁 结束");
System.out.println();
System.out.println();

System.out.println(" add 李宁 开始");
set.add(new Account("李宁",2,3000));
System.out.println(" add 李宁 结束");
System.out.println();
System.out.println();

System.out.println(" add 王宁 开始");
set.add(new Account("王宁",3,2000));
System.out.println(" add 王宁 结束");
System.out.println();
System.out.println();

System.out.println(" add 钱宁 开始");
set.add(new Account("钱宁",24,6000));
System.out.println(" add 钱宁 结束");
for (Object o : set) {
	System.out.println(o);
}

}

}

Account.java中部分代码

@Override
	public int compareTo(Object object) {
		Account account = (Account) object;
		String firstName = this.name.substring(0, 1);
		String otherName = account.name.substring(0, 1);
//		System.out.println(firstName);
//		System.out.println(otherName);
		System.out.println("------------------");
		System.out.println("我是"+this.name+",和我比较的是："+account.name);
		System.out.println("-------------------");
		char fc = 0;
		char oc = 0;
		for (int i = 0; i < CompareTable.list.size(); i++) {
			String s[] = (String[]) CompareTable.list.get(i);
			if (s[0].equals(firstName)) {
				fc = s[1].toCharArray()[0];
				break;
			}
			if (s[0].equals(otherName)) {
				oc = s[1].toCharArray()[0];
				break;
			}
		}
		if (fc > oc)
			return -1;
		if (fc < oc)
			return 1;
		else
			return 0;
	}

2012年10月24日 17:11