Spring MVC 3<形式 ：选择>标签多选

Question

我需要在多重选择表单中选择多个值：选择标签。我的jsp代码是

<form:form id="myForm"
action="service.do" modelAttribute="services"
method="POST">
 ....
 ....

<form:select path="channelsInvolved" items="${allChannels}" itemValue="channelid" itemLabel="channelname"> 

我的控制器是...

List<Channels> channels = dao.getAllChannels();
model.addAttribute("allChannels", channels);

ServiceRegistration serRegistration = dao.getById(2);
model.put("services", serRegistration);

实际上，我有3个表-> ServiceRegistration、Channels（包含 META 数据）和 ServiceChannel。 ServiceChannel 包含服务注册和通道表的外键引用。因此，一个serviceid可以在servicechannel表中映射多个channelid。

我的 ServiceRegistration.java 实体类具有 ChannelsInvolved 字段作为...

@OneToMany(cascade=CascadeType.ALL,fetch = FetchType.EAGER)
 @JoinTable(name = "ServiceChannel", joinColumns = {
 @JoinColumn(name="serviceid", unique = true) 
 },
 inverseJoinColumns = {
 @JoinColumn(name="channelid")
 }
 )

 private List<Channels> channelsInvolved;

     public List<Channels> getChannelsInvolved() {
    return channelsInvolved;
  }

public void setChannelsInvolved(List<Channels> channelsInvolved) {
    this.channelsInvolved = channelsInvolved;
  }

Channel 实体类... Channels.java

@Id
@GeneratedValue(strategy = GenerationType.AUTO)
@Column private int channelid;
@Column private String channelname; 

ServiceChannel.java 实体类...

@Id
@GeneratedValue(strategy = GenerationType.AUTO)
@Column private int servicechannelid;    

@ManyToOne
@JoinColumn(name = "serviceid")
private ServiceRegistration serviceRegistration;

@ManyToOne
@JoinColumn(name = "channelid")
private Channels channels;

比如说，我有一个服务 id >>> 2 映射到channelid>> 1和2。我可以在“channelsInvolved”中看到2条记录。但是当我将 serRegistration 设置为 jsp 的模型属性时，选择标记中没有选择任何一个。

帮助表示赞赏，谢谢。

Answer 1

您将需要在实体中（尤其是在通道中）正确实现equals。