我像这样初始化HashSet:
private HashSet<Rule> ruleTable = new HashSet<Rule>();
我的
equals()
对象(抽象类hashCode()
的子类)的TcpRule
和Rule
方法如下所示:@Override
public int hashCode() {
// Ignore source Port for now
return (this.getSrcPool() + ":" + this.getDstPool() + ":" + this.getProtocol() + ":" + this.dstTcp).hashCode();
}
@Override
public boolean equals(Object obj) {
if (!(obj instanceof TcpRule))
return false;
if (obj == this)
return true;
TcpRule r = (TcpRule) obj;
return (this.getSrcPool().equals(r.getSrcPool()) && this.getDstPool().equals(r.getDstPool()) && this.getProtocol().equals(r.getProtocol()) && this.getSrcTcp() == r.getSrcTcp() && this.getDstTcp() == r.getDstTcp());
}
我什至编写了一个简单的单元测试,没有给出任何错误:
@Test
public void equalsTest() {
Pool srcPool = new Pool("PROXY");
Pool dstPool = new Pool("WEB");
int srcTcp = 54321;
int dstTcp = 80;
TcpRule r1 = new TcpRule(srcPool, dstPool, srcTcp, dstTcp);
TcpRule r2 = r1;
assert r1.equals(r2);
TcpRule r3 = new TcpRule(srcPool, dstPool, srcTcp, dstTcp);
TcpRule r4 = new TcpRule(srcPool, dstPool, srcTcp, dstTcp);
assert r3.equals(r4);
}
@Test
public void hashCodeTest() {
Pool srcPool = new Pool("PROXY");
Pool dstPool = new Pool("WEB");
int srcTcp = 54321;
int dstTcp = 80;
TcpRule r1 = new TcpRule(srcPool, dstPool, srcTcp, dstTcp);
TcpRule r2 = new TcpRule(srcPool, dstPool, srcTcp, dstTcp);
assert r1.hashCode() == r2.hashCode();
HashSet<Rule> rules = new HashSet<Rule>();
rules.add(r1);
assert rules.contains(r1);
assert rules.contains(r2);
}
在我的应用程序中,我有一个
add()
方法,我只需在Rule
中添加一个HashSet
对象:@Override
public void add(Rule rule) {
ruleTable.add(rule);
}
在另一种方法中,我检查
HashSet
中是否存在规则: @Override
public boolean isPermittedTcp(IpAddress sourceAddress, IpAddress destinationAddress, short srcTcp, short dstTcp) {
Pool sourcePool = poolService.getPool(new Host(sourceAddress));
Pool destinationPool = poolService.getPool(new Host(destinationAddress));
Rule r = new TcpRule(sourcePool, destinationPool, srcTcp, dstTcp);
log.info("Checking: " + r.toString());
log.info("Hash-Code: " + r.hashCode());
log.info("Hashes in ruleTable:");
for(Rule rT : ruleTable) {
log.info("" + rT.hashCode());
}
if(ruleTable.contains(r)) {
log.info("Hash found!");
} else {
log.info("Hash not found!");
}
return ruleTable.contains(r);
}
日志消息指示
Rule
对象(r.hashCode()
)的哈希为-1313430269
,并且HashSet
(循环中为rT.hashCode()
)中的一个哈希也为-1313430269
。但是
ruleTable.contains(r)
总是返回false
。我究竟做错了什么?我在StackOverflow上发现了类似的问题,但这些问题大多涉及
equals()
或hashCode()
方法没有(正确)被覆盖。我认为我已经正确实现了这两种方法。 最佳答案
您的问题是hashCode()
和equals()
会执行而不是同意。
您的hashCode()
实现基于池的toString()
,但是equals()
使用池类的.equals()
。
更改.equals()
以比较用于生成哈希码的字符串。