Spring MVC 3 <form:Select> 标签多选

Question

我需要在多选表单中选择多个值：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 包含与 serviceregistration 和通道表的外键引用。所以，一个serviceid可能有多个channelid映射到servicechannel表中。

我的 ServiceRegistration.java 实体类的 channelsInvolved 字段为...

@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;

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，在 select 标记中没有选择任何内容。

感谢您的帮助，谢谢。

Answer 1

您需要在实体中正确实现equals（尤其是在Channels 中）。