av一区二区在线观看_亚洲男人的天堂网站_日韩亚洲视频_在线成人免费_欧美日韩精品免费观看视频_久草视

您的位置:首頁技術文章
文章詳情頁

錯誤:java.lang.NoSuchMethodException:java.lang.Long()在春季MVC中

瀏覽:85日期:2024-05-12 09:22:13
(adsbygoogle = window.adsbygoogle || []).push({}); 如何解決錯誤:java.lang.NoSuchMethodException:java.lang.Long()在春季MVC中?

這@modelattribute('studentId') LongstudentId是問題的根源,因為spring找不到可以提供此Long對象的方法,因此它試圖實例化一個對象并將其作為方法參數傳遞。 您可以:

@RequestMapping(value = '/read.html') public String readStudent(Model model,Long studentId) {Student student = null;studentId = 2l;try { student = serviceFile.readStudent(studentId);} catch(Exception e){ model.addAttribute('message', 'Some thing went wrong !!!! Exception occured'); return 'message';}model.addAttribute('student', student);return 'read'; } 在您的 中

@modelattribute public void provideStudentId(Model model){model.addAttribute('studentId', new Long(1)); }

官方文件

@RequestMapping(path = '/owners/{ownerId}/pets/{petId}/edit', method = RequestMethod.POST) public String processSubmit(@modelattribute Pet pet) { }

給定以上示例,Pet實例可以從哪里來?有幾種選擇:

由于使用@SessionAttributes,它可能已經在模型中-請參閱“使用@SessionAttributes在請求之間的HTTP會話中存儲模型屬性”一節。由于同一控制器中的@modelattribute方法,它可能已經在模型中-如上一節中所述。可以基于URI模板變量和類型轉換器(在下面更詳細地說明)來檢索它。可以使用其默認構造函數實例化它。

如果studentId是參數的名字從你可以使用UI發送@RequestParam這樣

@RequestMapping(value = '/read.html') public String readStudent(Model model, @RequestParam('studentId') Long studentId) {Student student = null;studentId = 2l;try { student = serviceFile.readStudent(studentId);} catch(Exception e) { model.addAttribute('message', 'Some thing went wrong !!!! Exception occoured'); return 'message';} model.addAttribute('student', student);return 'read'; }解決方法

從數據庫讀取學生對象時出現此錯誤。

org.springframework.beans.BeanInstantiationException: Failed to instantiate [java.lang.Long]: No default constructor found; nested exception is java.lang.NoSuchMethodException: java.lang.Long.<init>()org.springframework.beans.BeanUtils.instantiateClass(BeanUtils.java:107)

全棧跟蹤:

org.springframework.web.util.NestedServletException: Request processing failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [java.lang.Long]: No default constructor found; nested exception is java.lang.NoSuchMethodException: java.lang.Long.<init>() org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:978) org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:857) javax.servlet.http.HttpServlet.service(HttpServlet.java:617) org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:842) javax.servlet.http.HttpServlet.service(HttpServlet.java:717)root causeorg.springframework.beans.BeanInstantiationException: Failed to instantiate [java.lang.Long]: No default constructor found; nested exception is java.lang.NoSuchMethodException: java.lang.Long.<init>() org.springframework.beans.BeanUtils.instantiateClass(BeanUtils.java:107) org.springframework.web.bind.annotation.support.HandlerMethodInvoker.resolveModelAttribute(HandlerMethodInvoker.java:775) org.springframework.web.bind.annotation.support.HandlerMethodInvoker.resolveHandlerArguments(HandlerMethodInvoker.java:368) org.springframework.web.bind.annotation.support.HandlerMethodInvoker.invokeHandlerMethod(HandlerMethodInvoker.java:172) org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter.invokeHandlerMethod(AnnotationMethodHandlerAdapter.java:446) org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter.handle(AnnotationMethodHandlerAdapter.java:434) org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:943) org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:877) org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:966) org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:857) javax.servlet.http.HttpServlet.service(HttpServlet.java:617) org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:842) javax.servlet.http.HttpServlet.service(HttpServlet.java:717)root causejava.lang.NoSuchMethodException: java.lang.Long.<init>() java.lang.Class.getConstructor0(Class.java:3082) java.lang.Class.getDeclaredConstructor(Class.java:2178) org.springframework.beans.BeanUtils.instantiateClass(BeanUtils.java:104) org.springframework.web.bind.annotation.support.HandlerMethodInvoker.resolveModelAttribute(HandlerMethodInvoker.java:775) org.springframework.web.bind.annotation.support.HandlerMethodInvoker.resolveHandlerArguments(HandlerMethodInvoker.java:368) org.springframework.web.bind.annotation.support.HandlerMethodInvoker.invokeHandlerMethod(HandlerMethodInvoker.java:172) org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter.invokeHandlerMethod(AnnotationMethodHandlerAdapter.java:446) org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter.handle(AnnotationMethodHandlerAdapter.java:434) org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:943) org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:877) org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:966) org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:857) javax.servlet.http.HttpServlet.service(HttpServlet.java:617) org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:842) javax.servlet.http.HttpServlet.service(HttpServlet.java:717)

學生.java

@Entity@Table(name='Student')public class Student implements Serializable{ private static final long serialVersionUID = 1L; @Id @GeneratedValue(strategy=GenerationType.AUTO) @Column(name='studentId') Long studentId; @Column(name='studentName') String studentName;

Controller.java

@RequestMapping(value = '/read.html') public String readStudent(Model model,@ModelAttribute('studentId') Long studentId) {Student student = null;studentId = 2l;try{ student = serviceFile.readStudent(studentId);}catch(Exception e){ model.addAttribute('message','Some thing went wrong !!!! Exception occoured'); return 'message';} model.addAttribute('student',student);return 'read'; }

daoImpl.java

@Repository@Transactionalpublic class DaoImplFile implements DaoFile { private EntityManager entityManager; public EntityManager getEntityManager() {return entityManager; } @PersistenceContext public void setEntityManager(EntityManager entityManager) {this.entityManager = entityManager; } @Override public Student read(Long studentId) throws NullPointerException { Student student = entityManager.find(Student.class,studentId);if (student!=null) { return student;} else { return null;} }

標簽: java
相關文章:
主站蜘蛛池模板: 国产高清久久久 | 欧美一区二区三区大片 | www.操.com| 99久久久99久久国产片鸭王 | 91在线视频免费观看 | 欧美久久精品一级黑人c片 91免费在线视频 | 最新一级毛片 | 欧美日韩国产一区二区三区 | 精品欧美二区 | 成人精品一区二区三区 | 亚洲高清视频在线 | 一级片在线观看 | 国产精品久久久久久久岛一牛影视 | 亚洲第一视频网 | 久久久精品一区 | av三级在线观看 | 激情视频中文字幕 | 欧美黄色片在线观看 | 日韩一区在线播放 | 91免费福利在线 | 羞羞网站在线观看 | 国产午夜精品一区二区三区嫩草 | 国产欧美日韩一区 | 成人精品在线观看 | 一级黄色生活视频 | 亚洲伦理自拍 | 欧美成人手机在线 | 日韩视频一区在线观看 | 日韩一区中文字幕 | 国产视频一区二区三区四区五区 | 日本超碰 | 久久9热 | 久久伊人一区 | 精品无码三级在线观看视频 | 一区精品视频在线观看 | 久久久精品亚洲 | 丁香婷婷久久久综合精品国产 | 少妇黄色| 午夜免费网 | 精品国产91 | 欧洲妇女成人淫片aaa视频 |