我研究JSF 2.2和JPA 2.1
我有两个表格课程和单元这些表格有关系（每个课程可以有很多单元）
课程表有设置单元数的字段
当我使用单元数创建课程时，我想自动生成单元。
我试着这样做，但直到现在我才成功
单位实体类：
@Entity
@Table(catalog = "utechsacademy", schema = "", uniqueConstraints = {
@UniqueConstraint(columnNames = {"unit_id"})})
@XmlRootElement
@NamedQueries({
@NamedQuery(name = "Unit.findAll", query = "SELECT u FROM Unit u"),
@NamedQuery(name = "Unit.findByCourse", query = "SELECT u FROM Unit u WHERE u.courseId = :courseId"),
@NamedQuery(name = "Unit.findByUnitId", query = "SELECT u FROM Unit u WHERE u.unitId = :unitId"),
@NamedQuery(name = "Unit.findByUnitNumber", query = "SELECT u FROM Unit u WHERE u.unitNumber = :unitNumber")})
public class Unit implements Serializable {
private static final long serialVersionUID = 1L;
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
@Basic(optional = false)
@Column(name = "unit_id", nullable = false)
private Integer unitId;
@Basic(optional = false)
@NotNull
@Column(name = "unit_number", nullable = false)
private int unitNumber;
@OneToMany(cascade = CascadeType.ALL, mappedBy = "unitId")
private List<Lesson> lessonList;
@JoinColumn(name = "course_id", referencedColumnName = "course_id", nullable = false)
@ManyToOne(optional = false)
private Course courseId;
public Unit() {
}
public Unit(Integer unitId) {
this.unitId = unitId;
}
public Unit(Integer unitId, int unitNumber) {
this.unitId = unitId;
this.unitNumber = unitNumber;
}
public Integer getUnitId() {
return unitId;
}
public void setUnitId(Integer unitId) {
this.unitId = unitId;
}
public int getUnitNumber() {
return unitNumber;
}
public void setUnitNumber(int unitNumber) {
this.unitNumber = unitNumber;
}
@XmlTransient
public List<Lesson> getLessonList() {
return lessonList;
}
public void setLessonList(List<Lesson> lessonList) {
this.lessonList = lessonList;
}
public Course getCourseId() {
return courseId;
}
public void setCourseId(Course courseId) {
this.courseId = courseId;
}
@Override
public int hashCode() {
int hash = 0;
hash += (unitId != null ? unitId.hashCode() : 0);
return hash;
}
@Override
public boolean equals(Object object) {
// TODO: Warning - this method won't work in the case the id fields are not set
if (!(object instanceof Unit)) {
return false;
}
Unit other = (Unit) object;
if ((this.unitId == null && other.unitId != null) || (this.unitId != null && !this.unitId.equals(other.unitId))) {
return false;
}
return true;
}
@Override
public String toString() {
return "entities.Unit[ unitId=" + unitId + " ]";
}
}
这是创建课程的jsf页面：
<h:form id="CourseCreateForm" enctype="multipart/form-data">
<h:panelGroup id="display">
<p:panelGrid columns="2" rendered="#{courseController.selected != null}">
<p:outputLabel value="#{admin.CreateCourseLabel_sectionId}" for="sectionId" />
<h:selectOneMenu id="sectionId" value="#{courseController.selected.sectionId}" required="true" requiredMessage="#{admin.EditCourseRequiredMessage_sectionId}">
<f:selectItem itemLabel="Select One" itemValue="" noSelectionOption="true" />
<f:selectItems value="#{sectionController.itemsAvailableSelectOne}"
var="sectionIdItem"
itemLabel="#{sectionIdItem.sectionName}"
itemValue="#{sectionIdItem}"/>
</h:selectOneMenu>
<p:outputLabel value="#{admin.CreateCourseLabel_courseName}" for="courseName" />
<p:inputText id="courseName" value="#{courseController.selected.courseName}" title="#{admin.CreateCourseTitle_courseName}" required="true" requiredMessage="#{admin.CreateCourseRequiredMessage_courseName}"/>
<p:outputLabel value="#{admin.CreateCourseLabel_courseDesc}" for="courseDesc" />
<p:inputText id="courseDesc" value="#{courseController.selected.courseDesc}" title="#{admin.CreateCourseTitle_courseDesc}" required="true" requiredMessage="#{admin.CreateCourseRequiredMessage_courseDesc}"/>
<p:outputLabel value="#{admin.CreateCourseLabel_coursehours}" for="coursehours" />
<p:inputText id="coursehours" value="#{courseController.selected.coursehours}" title="#{admin.CreateCourseTitle_coursehours}" required="true" requiredMessage="#{admin.CreateCourseRequiredMessage_coursehours}"/>
<p:outputLabel value="#{admin.CreateCourseLabel_courseUnits}" for="courseUnits" />
<p:inputText id="courseUnits" value="#{courseController.selected.courseUnits}" title="#{admin.CreateCourseTitle_courseUnits}" required="true" requiredMessage="#{admin.CreateCourseRequiredMessage_courseUnits}"/>
<p:outputLabel value="#{admin.CreateCourseLabel_coursePoints}" for="coursePoints" />
<p:inputText id="coursePoints" value="#{courseController.selected.coursePoints}" title="#{admin.CreateCourseTitle_coursePoints}" required="true" requiredMessage="#{admin.CreateCourseRequiredMessage_coursePoints}"/>
<p:outputLabel value="#{admin.CreateCourseLabel_coursePhoto}" for="coursePhoto" />
<p:inputText id="coursePhoto" value="#{courseController.selected.coursePhoto}" title="#{admin.CreateCourseTitle_coursePhoto}" required="true" requiredMessage="#{admin.CreateCourseRequiredMessage_coursePhoto}"/>
<p:outputLabel value="test" for="coursePhotoa" />
<p:fileUpload id="coursePhotoa" auto="true" fileUploadListener="#{photoUploader.upload}" mode="simple" dragDropSupport="false" sizeLimit="100000" fileLimit="1" allowTypes="/(.|/)(gif|jpe?g|png)$/" />
<p:outputLabel value="#{admin.CreateCourseLabel_courseLevel}" for="courseLevel" />
<p:inputText id="courseLevel" value="#{courseController.selected.courseLevel}" title="#{admin.CreateCourseTitle_courseLevel}" required="true" requiredMessage="#{admin.CreateCourseRequiredMessage_courseLevel}"/>
<p:outputLabel value="#{admin.CreateCourseLabel_courseActive}" for="courseActive" />
<p:selectBooleanCheckbox id="courseActive" value="#{courseController.selected.courseActive}" required="true" requiredMessage="#{admin.EditCourseRequiredMessage_courseActive}"/>
<p:outputLabel value="#{admin.CreateCourseLabel_achievementId}" for="achievementId" />
<h:selectOneMenu id="achievementId" value="#{courseController.selected.achievementId}" >
<f:selectItem itemLabel="Select One" itemValue="" noSelectionOption="true" />
<f:selectItems value="#{achievementsController.itemsAvailableSelectOne}"
var="achievementIdItem"
itemLabel="#{achievementIdItem.achievementName}"
itemValue="#{achievementIdItem}"/>
</h:selectOneMenu>
<p:outputLabel value="#{admin.CreateCourseLabel_languageId}" for="languageId" />
<h:selectOneMenu id="languageId" value="#{courseController.selected.languageId}" required="true" requiredMessage="#{admin.EditCourseRequiredMessage_languageId}">
<f:selectItem itemLabel="Select One" itemValue="" noSelectionOption="true" />
<f:selectItems value="#{languageController.itemsAvailableSelectOne}"
var="languageIdItem"
itemLabel="#{languageIdItem.languageName}"
itemValue="#{languageIdItem}"/>
</h:selectOneMenu>
<p:outputLabel value="#{admin.CreateCourseLabel_quizId}" for="quizId" />
<h:selectOneMenu id="quizId" value="#{courseController.selected.quizId}" >
<f:selectItem itemLabel="Select One" itemValue="" noSelectionOption="true" />
<f:selectItems value="#{quizController.itemsAvailableSelectOne}"
var="quizIdItem"
itemLabel="#{quizIdItem.quizName}"
itemValue="#{quizIdItem}"/>
</h:selectOneMenu>
</p:panelGrid>
<p:commandButton actionListener="#{courseController.create}" value="#{admin.Save}" update="display,:CourseListForm:datalist,:growl" oncomplete="handleSubmit(args,'CourseCreateDialog');">
<f:actionListener binding="#{courseController.createUnit}" />
</p:commandButton>
<p:commandButton value="#{admin.Cancel}" onclick="PF('CourseCreateDialog').hide()"/>
</h:panelGroup>
</h:form>
和这个创建方法在课程管理豆：
public void create() {
persist(PersistAction.CREATE, ResourceBundle.getBundle("/Admin").getString("CourseCreated"));
if (!JsfUtil.isValidationFailed()) {
items = null; // Invalidate list of items to trigger re-query.
}
}
首先要说明的是：
- 您不应该添加带有id的构造函数。带有
@GeneratedValue的id是由您的JPA提供程序（即您的数据库）自动设置的，即使没有构造函数也是如此（同样适用于setUnitId） - 你不需要
@JoinColumn注释，@ManyToOne(optional = false)注释就足够了——只要你把课程称为course（而不是courseId） - 您展示的是
Unit实现，但谈论的却是Course实体
然而，结果是一样的：
public class Course {
...
@OneToMany(mappedBy = "course", cascade = CascadeType.ALL, orphanRemoval = true)
private List<Unit> units = new ArrayList<>();
public int getCourseUnits() {
return units.size();
}
public void setCourseUnits(int numberOfUnits) {
if (units.size() > numberOfUnits) {
units.sublist(numberOfUnits, units.size()).clear();
} else {
for (int i = units.size(); i < numberOfUnits; i++) {
Unit unit = new Unit();
unit.setUnitNumber(i);
units.add(unit);
}
}
}
}