想新增一个类似菜单，部门的页面，根据菜单和部门的接口写了一个接口，但是查询数据时空指针异常

Blade 未结

关注举报

 1  210

wensheng 剑童 2024-06-24 19:38

一、该问题的重现步骤是什么？

新增了类似菜单部门的页面，后端创建了实体类，如图

@Data
@TableName("erp_product_type")
@EqualsAndHashCode(callSuper = true)
@ApiModel(value = "ProductType对象", description = "商品分类信息表")
public class ProductType extends BaseEntity {

    private static final long serialVersionUID = 1L;

    /**
     * 唯一识别码
     */
    @ApiModelProperty(value = "唯一识别码")
    @JsonSerialize(using = ToStringSerializer.class)
    private Long id;
    /**
     * 商品类别编码
     */
    @ApiModelProperty(value = "商品类别编码")
    private String productTypeCode;
    /**
     * 商品类别名称
     */
    @ApiModelProperty(value = "商品类别名称")
    private String productTypeName;
    /**
     * 商品类别父级编码
     */
    @ApiModelProperty(value = "商品类别父级编码")
    @JsonSerialize(using = ToStringSerializer.class)
    private Long parentId;
    /**
     * 备注
     */
    @ApiModelProperty(value = "备注")
    private String remark;


}

2. 创建了具体的VO类

@Data
@EqualsAndHashCode(callSuper = true)
@ApiModel(value = "ProductTypeVO对象", description = "商品分类信息表")
public class ProductTypeVO extends ProductType  implements INode<ProductTypeVO> {
    private static final long serialVersionUID = 1L;

    /**
     * 主键ID
     */
    @JsonSerialize(using = ToStringSerializer.class)
    private Long id;

    /**
     * 父节点ID
     */
    @JsonSerialize(using = ToStringSerializer.class)
    private Long parentId;

    /**
     * 子孙节点
     */
    @JsonInclude(JsonInclude.Include.NON_EMPTY)
    private List<ProductTypeVO> children;

    /**
     * 是否有子孙节点
     */
    @JsonInclude(JsonInclude.Include.NON_EMPTY)
    private Boolean hasChildren;


    @Override
    public List<ProductTypeVO> getChildren() {
       return Collections.emptyList();
    }

    /**
     * 上级分类
     */
    private String parentName;
}

3.创建了Wrapper类

<, > {

    ;

    {
       = .(.);
    }
    () {
       ProductTypeWrapper();
    }
    () {
       = .(, .);
       (.(.getParentId(), .)) {
          .setParentName(.);
       } {
          = .getById(.getParentId());
          .setParentName(.getProductTypeName());
       }
       ;
    }

    <> (<> ) {
       <> = .stream().map(-> .(, .)).collect(.());
       .();
    }
}

4.修改controller接口

()
(order = )
(value = , notes = )
<<>> (, ) {
    <> = .list( .());
    .(.().listNodeVO());
}

二、你期待的结果是什么？实际看到的又是什么？

期待结果应当是返回一个树形结构的数据，结果实际情况有报错，报错情况如下

va.lang.UnsupportedOperationException: null

at java.util.AbstractList.add(AbstractList.java:148) ~[na:1.8.0_381]

at java.util.AbstractList.add(AbstractList.java:108) ~[na:1.8.0_381]

at org.springblade.core.tool.node.ForestNodeMerger.lambda$merge$0(ForestNodeMerger.java:41) ~[blade-core-tool-3.7.1.jar:na]

at java.util.ArrayList.forEach(ArrayList.java:1259) ~[na:1.8.0_381]

at org.springblade.core.tool.node.ForestNodeMerger.merge(ForestNodeMerger.java:37) ~[blade-core-tool-3.7.1.jar:na]

at org.springblade.erp.wrapper.ProductTypeWrpper.listNodeVO(ProductTypeWrpper.java:49) ~[classes/:na]

at org.springblade.erp.controller.ProductTypeController.list(ProductTypeController.java:73) ~[classes/:na]

at org.springblade.erp.controller.ProductTypeController$$FastClassBySpringCGLIB$$8afce32b.invoke(<generated>) ~[classes/:na]

at org.springframework.cglib.proxy.MethodProxy.invoke(MethodProxy.java:218) ~[spring-core-5.3.31.jar:5.3.31]

at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.invokeJoinpoint(CglibAopProxy.java:792) ~[spring-aop-5.3.31.jar:5.3.31]

at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:163) ~[spring-aop-5.3.31.jar:5.3.31]

at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.proceed(CglibAopProxy.java:762) ~[spring-aop-5.3.31.jar:5.3.31]

at org.springframework.aop.aspectj.MethodInvocationProceedingJoinPoint.proceed(MethodInvocationProceedingJoinPoint.java:89) ~[spring-aop-5.3.31.jar:5.3.31]

at org.springblade.core.boot.logger.RequestLogAspect.aroundApi(RequestLogAspect.java:158) ~[blade-core-boot-3.7.1.jar:na]

at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_381]

at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_381]

at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_381]

at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_381]

at org.springframework.aop.aspectj.AbstractAspectJAdvice.invokeAdviceMethodWithGivenArgs(AbstractAspectJAdvice.java:634) ~[spring-aop-5.3.31.jar:5.3.31]

at org.springframework.aop.aspectj.AbstractAspectJAdvice.invokeAdviceMethod(AbstractAspectJAdvice.java:624) ~[spring-aop-5.3.31.jar:5.3.31]

at org.springframework.aop.aspectj.AspectJAroundAdvice.invoke(AspectJAroundAdvice.java:72) ~[spring-aop-5.3.31.jar:5.3.31]

at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:175) ~[spring-aop-5.3.31.jar:5.3.31]

at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.proceed(CglibAopProxy.java:762) ~[spring-aop-5.3.31.jar:5.3.31]

at org.springframework.aop.interceptor.ExposeInvocationInterceptor.invoke(ExposeInvocationInterceptor.java:97) ~[spring-aop-5.3.31.jar:5.3.31]

at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.3.31.jar:5.3.31]

at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.proceed(CglibAopProxy.java:762) ~[spring-aop-5.3.31.jar:5.3.31]

at org.springframework.aop.framework.CglibAopProxy$DynamicAdvisedInterceptor.intercept(CglibAopProxy.java:707) ~[spring-aop-5.3.31.jar:5.3.31]

at org.springblade.erp.controller.ProductTypeController$$EnhancerBySpringCGLIB$$c498aa55.list(<generated>) ~[classes/:na]

at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_381]

at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_381]

at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_381]

at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_381]

at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:205) ~[spring-web-5.3.31.jar:5.3.31]

at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:150) ~[spring-web-5.3.31.jar:5.3.31]

at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:117) ~[spring-webmvc-5.3.31.jar:5.3.31]

at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:895) ~[spring-webmvc-5.3.31.jar:5.3.31]

at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:808) ~[spring-webmvc-5.3.31.jar:5.3.31]

at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87) ~[spring-webmvc-5.3.31.jar:5.3.31]

at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1072) ~[spring-webmvc-5.3.31.jar:5.3.31]

at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:965) ~[spring-webmvc-5.3.31.jar:5.3.31]

at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1006) [spring-webmvc-5.3.31.jar:5.3.31]

at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:898) [spring-webmvc-5.3.31.jar:5.3.31]

at javax.servlet.http.HttpServlet.service(HttpServlet.java:497) [jakarta.servlet-api-4.0.4.jar:4.0.4]

at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:883) [spring-webmvc-5.3.31.jar:5.3.31]

at javax.servlet.http.HttpServlet.service(HttpServlet.java:584) [jakarta.servlet-api-4.0.4.jar:4.0.4]

at io.undertow.servlet.handlers.ServletHandler.handleRequest(ServletHandler.java:74) [undertow-servlet-2.2.28.Final.jar:2.2.28.Final]

at io.undertow.servlet.handlers.FilterHandler$FilterChainImpl.doFilter(FilterHandler.java:129) [undertow-servlet-2.2.28.Final.jar:2.2.28.Final]

at org.springblade.core.tool.request.BladeRequestFilter.doFilter(BladeRequestFilter.java:57) [blade-core-tool-3.7.1.jar:na]