我有一对多类别产品关系：

public class**Category**{

    @Version
    private Integer version;

    @OneToMany(mappedBy = "category", cascade = {CascadeType.ALL})
    //@OptimisticLock(excluded = true)
    private List<Product> products
....

}

多到一边：

public class**Product**{

    @Version
    private Integer version;

    @ManyToOne
    @JoinColumn(name = "category_id")
    @ForeignKey(name = "fk_category_product")
    //@OptimisticLock(excluded = true)
    private Category category
....

}

我想防止丢失修改，所以我定义了一个版本机制（并发控制），如上所述。
但是，当我想保存父实体（类别）时，会出现以下错误：
无法执行语句；sql[不适用]；约束[john.sys_c0090239]；嵌套异常为org.hibernate.exception.constraintviolationexception:无法执行语句
以下是我的操作、服务和dao层：

行动

public String save() throws Exception {

        try {

            categoryManager.saveCategory(category);

        }catch (CategoryExistException e){
            List<Object> args = new ArrayList<Object>();
            args.add(category.getCategoryName());//categoryName is UNIQUE
            addActionError(getText("errors.existing.category", args));
            return INPUT;
        }

}

经理

@Override
public Category saveCategory(Category category) throws CategoryExistException{

    if (category.getVersion()==null)
    {
        // if new category, lowercase categoryId
        category.setCategoryName(category.getCategoryName().toLowerCase());
    }

    try {
        return categoryDao.saveCategory(category);
    } catch (final Exception e) {
        e.printStackTrace();
        log.warn(e.getMessage());
        throw new CategoryExistException("Category '" + category.getCategoryName() + "' already exists!");
    }
}

刀

@Override
public Category saveCategory(Category category){

    if (log.isDebugEnabled()) {
        log.debug("category's id: " + category.getCategoryId());
    }

    getSession().saveOrUpdate(category);
    //getSession().merge(category);

    // necessary to throw a DataIntegrityViolation and catch it in CategoryManger
    getSession().flush();

    return category;
}