Hibernate buiseness key equals（）不起作用

Question

我正在使用Hibernate来存储使用jsoup解析html的数据。这是我的实体：

Sentence.hbm.xml

<class name="Sentence">
    <id name="id">
            <column name="SENTENCE_ID"/>
            <generator class="native" />            
    </id>
   <property name="content" type="text"/>
   <many-to-one name="processedurl" class="src.model.ProcessedUrl">
        <column name="PROCESSED_URL_ID" not-null="true" /> 
   </many-to-one>                     
</class>

ProcessedUrl.hbm.xml

<class name="ProcessedUrl">
    <id name="id">
            <column name="url_id" />
            <generator class="native"/>
    </id>
    <property name="url" type="text"/>
    <property name="date" type="java.util.Date" />

    <set name="sentences" cascade="all">
        <key column="PROCESSED_URL_ID"/>    
        <one-to-many class="src.model.Sentence" />
    </set>                
</class>

POJO句子：

public class Sentence {

    private long id;
    private ProcessedUrl processedurl;
    private String content;

    public Sentence() 
    {
    }

    public Sentence(String content)
    {
        this.setContent(content);
        //this.setUrl(url);
    }

    public Sentence(String content, ProcessedUrl processed_url) {
        this.setContent(content);
        this.setProcessedurl(processed_url);
    }

    public long getId() {
        return id;
    }
    public void setId(long id) {
        this.id = id;
    }

    public ProcessedUrl getProcessedurl() {
        return processedurl;
    }

    public void setProcessedurl(ProcessedUrl processed_url) {
        this.processedurl = processed_url;
    }

    public String getContent() {
        return content;
    }

    public void setContent(String content) {
        this.content = content;
    }
}

POJO ProcessedUrl：

public class ProcessedUrl {

    private long id;
    private String url;
    private Date date;
    private Set<Sentence> sentences;

    public ProcessedUrl() {
    }

    public ProcessedUrl(String url, Date date) {
        this.setUrl(url);
        this.setDate(date);
    }
    public ProcessedUrl(String url, Date date, Set<Sentence> sentences) {
        this.setUrl(url);
        this.setDate(date);
        this.setSentences(sentences);
    }

    public long getId() {
        return id;
    }
    public void setId(long id) {
        this.id = id;
    }

    public String getUrl() {
        return url;
    }

    public void setUrl(String url) {
        this.url = url;
    }

    public Date getDate() {
        return date;
    }

    public void setDate(Date date) {
        this.date = date;
    }

    public Set<Sentence> getSentences() {
        return this.sentences;
    }

    public void setSentences(Set<Sentence> sentences) {
        this.sentences = sentences;
    }

    @Override
    public boolean equals(Object obj) {
        if(this == obj) return true;
        if(!(obj instanceof ProcessedUrl)) return false;

        ProcessedUrl that = (ProcessedUrl) obj;
        EqualsBuilder eb = new EqualsBuilder();
        eb.append(url, that.url);
        return eb.isEquals();
    }

    @Override
    public int hashCode() {
        HashCodeBuilder hcb = new HashCodeBuilder();
        hcb.append(url);
        return hcb.toHashCode();
        }       
}

索引方法：

public void indexWebPage(String url) throws IOException
    {   
        Document doc = Jsoup.connect(url).get();
        Elements elements = doc.body().select("*");
        HashSet<Sentence> sentencesCollection = new HashSet<Sentence>();
        ProcessedUrl processedUrl = new ProcessedUrl(url, new Date(), sentencesCollection);
        for (Element element : elements) 
        {
            if (element.ownText().trim().length() > 1)
            {
                for (String sentenceContent : element.ownText().split("\\. "))
                {                           
                    Sentence sentence = new Sentence(sentenceContent, processedUrl);
                    sentencesCollection.add(sentence);
                }
            }
        }
        Session session = HibernateUtils.getSession();
        Transaction transaction = session.beginTransaction();
        session.persist(processedUrl);
        transaction.commit();
        session.close();
}

这个方法正在解析一些http://...以后我从中创建一个Sentence，将它添加到HashSet中并在解析完所有内容之后我将带有这个填充的HasSet的ProcessedUrl对象添加到DB中，因为在xml文件中是级联设置就会填充Sentence表。它有效。但是，当我再次解析相同的链接时，它会复制两个表。我使用url作为buiseness键来覆盖equals（）/ hashcode（），我认为它会看到下一个解析的url之间的区别并且不会添加它（因此也不会添加句子）。但显然我并不清楚它是如何运作的。

一些提示＆amp;澄清？也许我的方式完全是愚蠢的？