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对我的英语提前感到抱歉。 我试图在实体列表中添加元素,并且只有第一个元素停留在此列表中。尝试将元素添加到JPA实体列表时出现奇怪的行为:只有第一个元素持续存在
下面的例子:
Project project = project_facade.find(1L);
Machine machine = machine_facade.find(1L);
for(int i=0;i<3;i++){
Test test = new Test();
test.setName("Test "+i);
test.setProject(project);
test.setMachine(machine);
project.getTestList().add(test);
machine.getTestList().add(test);
}
project.getMachineList().add(machine);
machine.getProjectList().add(project);
project_facade.edit(project);
此,在数据库中,该项目和设备是否正确连接(通过映射表),但测试表只包含记录“测试0”后( project_id字段和machine_id字段是正确的)。
我不明白为什么它是只有第一单元工作...
感谢您的帮助!
项目实体:
@Entity
public class Project implements Serializable {
private static final long serialVersionUID = 1L;
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
@Basic(optional = false)
@Column(name = "id")
private Long id;
@Basic(optional = false)
@NotNull
@Size(min = 1, max = 45)
@Column(name = "name")
private String name;
@ManyToMany(mappedBy = "projectList", cascade = CascadeType.ALL)
private List<Machine> machineList;
@OneToMany(mappedBy = "project", cascade = CascadeType.ALL *SOLUTION : ,fetch = FetchType.EAGER*)
private List<Test> testList;
//constructor, getters, setters
}
机实体:
@Entity
public class Machine implements Serializable {
private static final long serialVersionUID = 1L;
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
@Basic(optional = false)
@Column(name = "id")
private Long id;
@Basic(optional = false)
@NotNull
@Size(min = 1, max = 45)
@Column(name = "name")
private String name;
@JoinTable(name = "project_machine", joinColumns = {
@JoinColumn(name = "machine", referencedColumnName = "id")}, inverseJoinColumns = {
@JoinColumn(name = "project", referencedColumnName = "id")})
@ManyToMany
private List<Project> projectList;
@OneToMany(mappedBy = "machine",cascade = CascadeType.ALL)
private List<Test> testList;
//constructor, getters, setters
}
测试实体:
@Entity
public class Test implements Serializable {
private static final long serialVersionUID = 1L;
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
@Basic(optional = false)
@Column(name = "id")
private Long id;
@Basic(optional = false)
@NotNull
@Size(min = 1, max = 64)
@Column(name = "name")
private String name;
@JoinColumn(name = "project", referencedColumnName = "id")
@ManyToOne(optional = false)
private Project project;
@JoinColumn(name = "machine", referencedColumnName = "id")
@ManyToOne(optional = false)
private Machine machine;
//constructor, getters, setters
}
然后我所有的外墙伸出AbstractFacade这里编辑方法是:
public void edit(T entity) {
getEntityManager().merge(entity);
}
请向我们展示这两个实体以及执行'project_facade.edit()' – crizzis
当然,做完了 – Nep
'getTestList()'?第一个元素应该实际上是“测试0”吗? – pirho