将List中的对象中的字段的重复值删除

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如下面的对象 Subs，如果其属性 startSt 和 endSt 同时有重复的值，则删除其中重复的一个。

 

主要代码:

List results = new CopyOnWriteArrayList();

for (Object obj : list) {
	if (!results.contains(obj)) {
		results.add((Subs) obj);
	}
}

 

 

注：对象 Subs 中必须要重写 equals 方法。

 

class Subs {

	private String startSt;
	private String endSt;

	public String toString() {

		StringBuilder buf = new StringBuilder();

		buf.append("Subs:[");
		buf.append("startSt=").append(startSt).append(", ");
		buf.append("endSt=").append(endSt);
		buf.append("]");

		return buf.toString();
	}

	public boolean equals(Object obj) {
		if (obj == null) {
			return false;
		}

		if (obj instanceof Subs) {

			Subs other = (Subs) obj;

			if (this.getStartSt().equals(other.getStartSt())
					&& this.getEndSt().equals(other.getEndSt())) {
				return true;
			}
		}

		return false;
	}

	// 省略 setter/getter
}

 

测试（junit4）：

 

import java.util.LinkedList;
import java.util.List;
import java.util.concurrent.CopyOnWriteArrayList;

import org.junit.Test;

@Test
public void test() {

	List list = new LinkedList();

	Subs s1 = new Subs();

	s1.setStartSt("桂林变");
	s1.setEndSt("罗平站");

	list.add(s1);

	Subs s2 = new Subs();

	s2.setStartSt("桂林变");
	s2.setEndSt("挡村变电站");

	list.add(s2);

	Subs s3 = new Subs();

	s3.setStartSt("国安站");
	s3.setEndSt("尖峰站");

	list.add(s3);

	Subs s4 = new Subs();

	s4.setStartSt("迁岗站");
	s4.setEndSt("庙岭站");

	list.add(s4);

	Subs s5 = new Subs();

	s5.setStartSt("迁岗站");
	s5.setEndSt("庙岭站");

	list.add(s5);

	System.out.println("去重前:" + list);

	List results = new CopyOnWriteArrayList();

	for (Object obj : list) {
		if (!results.contains(obj)) {
			results.add((Subs) obj);
		}
	}

	System.out.println("去重后:" + results);
}

 

重复的数据是：startSt=迁岗站, endSt=庙岭站

 

结果：

去重前:[Subs:[startSt=桂林变, endSt=罗平站], Subs:[startSt=桂林变, endSt=挡村变电站], 
Subs:[startSt=国安站, endSt=尖峰站], Subs:[startSt=迁岗站, endSt=庙岭站], 
Subs:[startSt=迁岗站, endSt=庙岭站]]


去重后:[Subs:[startSt=桂林变, endSt=罗平站], Subs:[startSt=桂林变, endSt=挡村变电站], 
Subs:[startSt=国安站, endSt=尖峰站], Subs:[startSt=迁岗站, endSt=庙岭站]]