Spring 表单无法匹配集合。 ResponseStatusExceptionResolver ....类型不匹配

Question

我关注class:

public class TerminalAdmin {

    ....
    private Set<AdminRole> adminRoles;
}

还有这个：

public class AdminRole {
    ....
    private Long adminId;       
    private String role;
}

控制器：

model.addAttribute("adminRoles",terminalAdminService.findAllAdminRoles());
model.addAttribute("newAdmin",new TerminalAdmin());
return "admin/adminUsers";

jsp:

<form:form modelAttribute="newAdmin" action="/admin/addNewAdmin">            
    <div class="line">
            <label for="">role</label>
            <form:checkboxes items="${adminRoles}" path="adminRoles"/>
            <div class="clear"></div>
     </div>
     <div class="line">
            <input class="btn" type="submit" value="save"/>
            <div class="clear"></div>
     </div>
</form:form>

当我提交 foem 时，我看到消息：

HTTP Status 400 -

type Status report

message

description The request sent by the client was syntactically incorrect.

Spring 日志：

Field error in object 'terminalAdmin' on field 'adminRoles': rejected value [ROLE_IMAGE_MODERATOR]; codes [typeMismatch.terminalAdmin.adminRoles,typeMismatch.adminRoles,typeMismatch.java.util.Set,typeMismatch]; arguments [org.springframework.context.support.DefaultMessageSourceResolvable: codes [terminalAdmin.adminRoles,adminRoles]; arguments []; default message [adminRoles]]; default message [Failed to convert property value of type 'java.lang.String' to required type 'java.util.Set' for property 'adminRoles'; nested exception is java.lang.IllegalStateException: Cannot convert value of type [java.lang.String] to required type [com.terminal.domain.admin.AdminRole] for property 'adminRoles[0]': no matching editors or conversion strategy found]
DEBUG: org.springframework.web.servlet.mvc.annotation.ResponseStatusExceptionResolver - Resolving exception from handler [public java.lang.String com.terminal.controller.admin.AdminController.adminUsers(com.terminal.domain.admin.TerminalAdmin)]: org.springframework.validation.BindException: org.springframework.validation.BeanPropertyBindingResult: 1 errors
Field error in object 'terminalAdmin' on field 'adminRoles': rejected value [ROLE_IMAGE_MODERATOR]; codes [typeMismatch.terminalAdmin.adminRoles,typeMismatch.adminRoles,typeMismatch.java.util.Set,typeMismatch]; arguments [org.springframework.context.support.DefaultMessageSourceResolvable: codes [terminalAdmin.adminRoles,adminRoles]; arguments []; default message [adminRoles]]; default message [Failed to convert property value of type 'java.lang.String' to required type 'java.util.Set' for property 'adminRoles'; nested exception is java.lang.IllegalStateException: Cannot convert value of type [java.lang.String] to required type [com.terminal.domain.admin.AdminRole] for property 'adminRoles[0]': no matching editors or conversion strategy found]
DEBUG: org.springframework.web.servlet.mvc.support.DefaultHandlerExceptionResolver - Resolving exception from handler [public java.lang.String com.terminal.controller.admin.AdminController.adminUsers(com.terminal.domain.admin.TerminalAdmin)]: org.springframework.validation.BindException: org.springframework.validation.BeanPropertyBindingResult: 1 errors
Field error in object 'terminalAdmin' on field 'adminRoles': rejected value [ROLE_IMAGE_MODERATOR]; codes [typeMismatch.terminalAdmin.adminRoles,typeMismatch.adminRoles,typeMismatch.java.util.Set,typeMismatch]; arguments [org.springframework.context.support.DefaultMessageSourceResolvable: codes [terminalAdmin.adminRoles,adminRoles]; arguments []; default message [adminRoles]]; default message [Failed to convert property value of type 'java.lang.String' to required type 'java.util.Set' for property 'adminRoles'; nested exception is java.lang.IllegalStateException: Cannot convert value of type [java.lang.String] to required type [com.terminal.domain.admin.AdminRole] for property 'adminRoles[0]': no matching editors or conversion strategy found]

如何重写代码以避免以下错误？

Answer 1

您收到的错误消息很明确：您必须设置一个属性编辑器或转换服务，让活页夹知道如何从字符串中创建 AdminRole 对象（这是您实际拥有的每个复选框）。

如果您检查 jsp 页面源代码，您可能会看到该复选框表示为一个字符串数组（事实上，您会看到与该复选框相同的字段名称条目大小）。当您 post 表单时，活页夹会尝试创建一个 AdminRoles 集合，但如果不存在适当的转换策略，它所能做的最好的事情就是从数组中创建一个字符串集合。

Answer 2

我使用以下代码解决了问题：

    @InitBinder
    public void initBinder(WebDataBinder binder) {
        binder.registerCustomEditor(AdminRole.class,  new PropertyEditorSupport() {
            public void setAsText(String name) {
                AdminRole adminRole = terminalAdminService.findRoleByName(name);
                setValue(adminRole);
            }
        });
    }

Spring 表单无法匹配集合。 ResponseStatusExceptionResolver ....类型不匹配

Spring form cannot match collection. ResponseStatusExceptionResolver ....typeMismatch

java

spring

spring-mvc

spring-form