Java Hiibernate Web应用程序中的NPE

我正在开发一个Hibernate项目，该项目需要教师通过表单注册

Teacheradd.jsp

<%@page import="java.time.LocalDateTime"%>
<%@page import="java.util.Calendar"%>
<%@include file="header.jsp"%>
<div class="row">
    <div class="col-lg-offset-2 col-lg-8 col-lg-offset-2">
        <form class="border" action="addTeacher" method="post" style="">
            <center><h2 style="color: whitesmoke">Sign Up</h2><hr style="margin:0px" /></center>
            <div style="z-index: 100; background: whitesmoke">
            <div class="input-group">
                <label for="">Enter Name</label><req>*</req>
                    <input class="form-control" type="text" required="true" name="name" placeholder="Enter Name"/>
            </div>
            <div class="input-group">
                    <label for="">Enter Father`s Name</label><req>*</req>
                    <input class="form-control" type="text" required="true" name="fname" placeholder="Enter Father`s Name"/>
            </div>
            <div class="input-group">
                    <label for="">Enter DOB</label><req>*</req>
                    <input class="form-control" type="date" required="true" name="dob" max="<%out.print((LocalDateTime.now().getYear()-18) + "-01-01");%>"/>
            </div>
            <div class="input-group">
                    <label for="">Enter Gender</label><req>*</req><br/>
                    <select name="gender" class="form-control">
                            <option value="0">Male</option>
                            <option value="1">Female</option>
                    </select>
            </div>

            <div class="input-group">
                    <label for="">Enter Phone Number</label><req>*</req>
                    <input class="form-control" type="number" required="true" name="phone" placeholder="Enter Phone"/>
            </div>
            <div class="input-group">
                    <label for="">Enter Email</label><req>*</req>
                    <input class="form-control" type="text" required="true" name="email" placeholder="Enter Email"/>
            </div>
            <div class="input-group">
                    <label for="">Enter Address</label><req>*</req>
                    <input class="form-control" type="text" required="true" name="address1" placeholder="Address Line 1"/>
            </div>
            <div class="input-group">
                    <input class="form-control" type="text" name="address2" placeholder="Address Line 2"/>
            </div>
            <div class="input-group">
                    <input class="form-control" type="text" required="true" name="city" placeholder="City"/>
            </div>
            <div class="input-group">
                    <input class="form-control" type="number" required="true" name="pincode" placeholder="Pincode"/>
            </div>
            <div class="input-group">
                    <input class="form-control" type="text" required="true" name="state" placeholder="State"/>
            </div>
            <div class="input-group">
                <%@include file="countrylistselect.jsp" %>
            </div>
            <div class="input-group">
                    <label for="">Joining Date</label><req>*</req>
                    <input class="form-control" type="date" required="true" name="joindate" value="<%out.print(LocalDateTime.now().toLocalDate());%>" />
            </div>
            <div class="input-group">
                    <label for="">Enter Password</label><req>*</req>
                    <input class="form-control" type="password" required="true" name="pass" placeholder="Password"/>
            </div>
            <div class="input-group">
                    <label for="">Confirm Password</label><req>*</req>
                    <input class="form-control" type="password" required="true" name="pass2" placeholder="Re-type Password"/>
            </div>
            <center>
                <input type="checkbox" name="accept-eula" id="eula"/> <label for="eula">By checking this box, I agree to <a href="#">all terms</a> to use Teacher<sup>TM</sup></label><br/>
                    <input type="submit" value="Sign Up" class="btn btn-info" style="margin-bottom: 10px"/>
            </center>
            </div>
        </form>
    </div>
</div>
<div class="clearfix"></div>
<%@include file="footer.jsp" %>

及

Teacher.java

package com.newidea.tottracker.mappings;
// Generated 17 Feb, 2016 11:21:31 PM by Hibernate Tools 3.6.0


import java.time.LocalDate;
import java.time.LocalDateTime;
import java.util.HashSet;
import java.util.Set;

/**
 * Teacher generated by hbm2java
 */
public class Teacher  implements java.io.Serializable {


     private Integer teacherId;
     private String teacherName;
     private String teacherFname;
     private LocalDate teacherDob;
     private int teacherGender;
     private String teacherPhone;
     private String address1;
     private String address2;
     private String city;
     private int pincode;
     private String state;
     private String country;
     private String teacherEmail;
     private String teacherStatus;
     private LocalDate teacherDoj;
     private LocalDateTime teacherLastLogin;
     private String teacherLastLoginIp;
     private String teacherLevel;
     private Set classrooms = new HashSet(0);

    public Teacher() {
    }


    public Teacher(String teacherName, String teacherFname, LocalDate teacherDob, int teacherGender, String teacherPhone, String address1, String city, int pincode, String state, String country, String teacherEmail, String teacherStatus, LocalDate teacherDoj, LocalDateTime teacherLastLogin, String teacherLastLoginIp, String teacherLevel) {
        this.teacherName = teacherName;
        this.teacherFname = teacherFname;
        this.teacherDob = teacherDob;
        this.teacherGender = teacherGender;
        this.teacherPhone = teacherPhone;
        this.address1 = address1;
        this.city = city;
        this.pincode = pincode;
        this.state = state;
        this.country = country;
        this.teacherEmail = teacherEmail;
        this.teacherStatus = teacherStatus;
        this.teacherDoj = teacherDoj;
        this.teacherLastLogin = teacherLastLogin;
        this.teacherLastLoginIp = teacherLastLoginIp;
        this.teacherLevel = teacherLevel;
    }
    public Teacher(String teacherName, String teacherFname, LocalDate teacherDob, int teacherGender, String teacherPhone, String address1, String address2, String city, int pincode, String state, String country, String teacherEmail, String teacherStatus, LocalDate teacherDoj, LocalDateTime teacherLastLogin, String teacherLastLoginIp, String teacherLevel, Set classrooms) {
       this.teacherName = teacherName;
       this.teacherFname = teacherFname;
       this.teacherDob = teacherDob;
       this.teacherGender = teacherGender;
       this.teacherPhone = teacherPhone;
       this.address1 = address1;
       this.address2 = address2;
       this.city = city;
       this.pincode = pincode;
       this.state = state;
       this.country = country;
       this.teacherEmail = teacherEmail;
       this.teacherStatus = teacherStatus;
       this.teacherDoj = teacherDoj;
       this.teacherLastLogin = teacherLastLogin;
       this.teacherLastLoginIp = teacherLastLoginIp;
       this.teacherLevel = teacherLevel;
       this.classrooms = classrooms;
    }

    public Integer getTeacherId() {
        return this.teacherId;
    }

    public void setTeacherId(Integer teacherId) {
        this.teacherId = teacherId;
    }
    public String getTeacherName() {
        return this.teacherName;
    }

    public void setTeacherName(String teacherName) {
        this.teacherName = teacherName;
    }
    public String getTeacherFname() {
        return this.teacherFname;
    }

    public void setTeacherFname(String teacherFname) {
        this.teacherFname = teacherFname;
    }
    public LocalDate getTeacherDob() {
        return this.teacherDob;
    }

    public void setTeacherDob(LocalDate teacherDob) {
        this.teacherDob = teacherDob;
    }
    public int getTeacherGender() {
        return this.teacherGender;
    }

    public void setTeacherGender(int teacherGender) {
        this.teacherGender = teacherGender;
    }
    public String getTeacherPhone() {
        return this.teacherPhone;
    }

    public void setTeacherPhone(String teacherPhone) {
        this.teacherPhone = teacherPhone;
    }
    public String getAddress1() {
        return this.address1;
    }

    public void setAddress1(String address1) {
        this.address1 = address1;
    }
    public String getAddress2() {
        return this.address2;
    }

    public void setAddress2(String address2) {
        this.address2 = address2;
    }
    public String getCity() {
        return this.city;
    }

    public void setCity(String city) {
        this.city = city;
    }
    public int getPincode() {
        return this.pincode;
    }

    public void setPincode(int pincode) {
        this.pincode = pincode;
    }
    public String getState() {
        return this.state;
    }

    public void setState(String state) {
        this.state = state;
    }
    public String getCountry() {
        return this.country;
    }

    public void setCountry(String country) {
        this.country = country;
    }
    public String getTeacherEmail() {
        return this.teacherEmail;
    }

    public void setTeacherEmail(String teacherEmail) {
        this.teacherEmail = teacherEmail;
    }
    public String getTeacherStatus() {
        return this.teacherStatus;
    }

    public void setTeacherStatus(String teacherStatus) {
        this.teacherStatus = teacherStatus;
    }
    public LocalDate getTeacherDoj() {
        return this.teacherDoj;
    }

    public void setTeacherDoj(LocalDate teacherDoj) {
        this.teacherDoj = teacherDoj;
    }
    public LocalDateTime getTeacherLastLogin() {
        return this.teacherLastLogin;
    }

    public void setTeacherLastLogin(LocalDateTime teacherLastLogin) {
        this.teacherLastLogin = teacherLastLogin;
    }
    public String getTeacherLastLoginIp() {
        return this.teacherLastLoginIp;
    }

    public void setTeacherLastLoginIp(String teacherLastLoginIp) {
        this.teacherLastLoginIp = teacherLastLoginIp;
    }
    public String getTeacherLevel() {
        return this.teacherLevel;
    }

    public void setTeacherLevel(String teacherLevel) {
        this.teacherLevel = teacherLevel;
    }
    public Set getClassrooms() {
        return this.classrooms;
    }

    public void setClassrooms(Set classrooms) {
        this.classrooms = classrooms;
    }




}

TeacherAction.java

/*
 * To change this license header, choose License Headers in Project Properties.
 * To change this template file, choose Tools | Templates
 * and open the template in the editor.
 */
package com.newidea.tottracker.action;

import com.newidea.tottracker.mappings.Teacher;
import org.hibernate.Session;
import org.hibernate.Transaction;

/**
 *
 * @author Mohit
 */
public class TeacherAction extends BaseAction {

    Session session;
    Transaction tx = null;
    Integer tid = null;

    public TeacherAction() {
        super();
    }

    public Integer addTeacher(Teacher teacher) {
        session = getSessionFactory().openSession();

        try {
            tx = session.beginTransaction();
            tid = (Integer) session.save(teacher);
            tx.commit();
        } catch (Exception e) {
            if (tx != null) {
                tx.rollback();
            }
            System.out.println("Exception : " + e.getMessage());
        } finally {
            session.close();
        }
        return tid;
    }

    public void deleteTeacher(Integer tid) {

        session = getSessionFactory().openSession();
        try{
            tx = session.beginTransaction();
            Teacher teacher = (Teacher) session.get(Teacher.class, tid);
            session.delete(teacher);
            tx.commit();
        }catch(Exception e){
            if(tx != null) tx.rollback();
            System.out.println("Exception : " + e.getMessage());
        }
        finally{
            session.close();
        }

    }

    public void updateTeacher(Integer tid, Teacher newTeacher){

        session = getSessionFactory().openSession();
        try{
            tx = session.beginTransaction();
            Teacher oldTeacher = (Teacher) session.get(Teacher.class, tid);
            oldTeacher.setTeacherName(newTeacher.getTeacherName());
            oldTeacher.setTeacherFname(newTeacher.getTeacherFname());
            oldTeacher.setTeacherDob(newTeacher.getTeacherDob());
            oldTeacher.setTeacherGender(newTeacher.getTeacherGender());
            oldTeacher.setTeacherPhone(newTeacher.getTeacherPhone());
            oldTeacher.setAddress1(newTeacher.getAddress1());
            oldTeacher.setAddress2(newTeacher.getAddress2());
            oldTeacher.setCity(newTeacher.getCity());
            oldTeacher.setPincode(newTeacher.getPincode());
            oldTeacher.setState(newTeacher.getState());
            oldTeacher.setCountry(newTeacher.getCountry());
            oldTeacher.setTeacherEmail(newTeacher.getTeacherEmail());
            oldTeacher.setTeacherStatus(newTeacher.getTeacherStatus());
            oldTeacher.setTeacherDoj(newTeacher.getTeacherDoj());
            oldTeacher.setTeacherLastLoginIp(newTeacher.getTeacherLastLoginIp());
//            oldTeacher.setTeacherLevel(newTeacher.getTeacherLevel());
            session.merge(oldTeacher);
            tx.commit();
        }catch(Exception e){
            if(tx != null) tx.rollback();
            System.out.println("Exception : " + e.getMessage());
        }
        finally{
            session.close();
        }

    }

}

以下是堆栈跟踪：

18-Feb-2016 17:04:54.313 SEVERE [http-nio-8080-exec-83] org.apache.catalina.core.StandardWrapperValve.invoke Servlet.service() for servlet [addTeacher] in context with path [/Hibernate] threw exception
 java.lang.NullPointerException
    at com.newidea.tottracker.servlets.addTeacher.addNewTeacher(addTeacher.java:146)
    at com.newidea.tottracker.servlets.addTeacher.doPost(addTeacher.java:89)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:648)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:291)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
    at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:217)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:106)
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:502)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:142)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79)
    at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:616)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:88)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:518)
    at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1091)
    at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:673)
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1500)
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.run(NioEndpoint.java:1456)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
    at java.lang.Thread.run(Thread.java:745)

和服务器日志：

18-Feb-2016 17:04:53.049 INFO [http-nio-8080-exec-83] org.hibernate.cfg.Configuration.addResource HHH000221: Reading mappings from resource: com/newidea/tottracker/mappings/ExamType.hbm.xml
18-Feb-2016 17:04:53.057 INFO [http-nio-8080-exec-83] org.hibernate.cfg.Configuration.addResource HHH000221: Reading mappings from resource: com/newidea/tottracker/mappings/Role.hbm.xml
18-Feb-2016 17:04:53.125 INFO [http-nio-8080-exec-83] org.hibernate.cfg.Configuration.addResource HHH000221: Reading mappings from resource: com/newidea/tottracker/mappings/Teacher.hbm.xml
18-Feb-2016 17:04:53.141 INFO [http-nio-8080-exec-83] org.hibernate.cfg.Configuration.addResource HHH000221: Reading mappings from resource: com/newidea/tottracker/mappings/Course.hbm.xml
18-Feb-2016 17:04:53.149 INFO [http-nio-8080-exec-83] org.hibernate.cfg.Configuration.doConfigure HHH000041: Configured SessionFactory: null
18-Feb-2016 17:04:53.269 INFO [http-nio-8080-exec-83] org.hibernate.service.jdbc.connections.internal.DriverManagerConnectionProviderImpl.configure HHH000402: Using Hibernate built-in connection pool (not for production use!)
18-Feb-2016 17:04:53.277 INFO [http-nio-8080-exec-83] org.hibernate.service.jdbc.connections.internal.DriverManagerConnectionProviderImpl.configure HHH000115: Hibernate connection pool size: 20
18-Feb-2016 17:04:53.277 INFO [http-nio-8080-exec-83] org.hibernate.service.jdbc.connections.internal.DriverManagerConnectionProviderImpl.configure HHH000006: Autocommit mode: false
18-Feb-2016 17:04:53.277 INFO [http-nio-8080-exec-83] org.hibernate.service.jdbc.connections.internal.DriverManagerConnectionProviderImpl.configure HHH000401: using driver [com.mysql.jdbc.Driver] at URL [jdbc:mysql://localhost:3306/sms?zeroDateTimeBehavior=convertToNull]
18-Feb-2016 17:04:53.277 INFO [http-nio-8080-exec-83] org.hibernate.service.jdbc.connections.internal.DriverManagerConnectionProviderImpl.configure HHH000046: Connection properties: {user=root}
18-Feb-2016 17:04:53.625 INFO [http-nio-8080-exec-83] org.hibernate.dialect.Dialect.<init> HHH000400: Using dialect: org.hibernate.dialect.MySQLDialect
18-Feb-2016 17:04:53.801 INFO [http-nio-8080-exec-83] org.hibernate.engine.transaction.internal.TransactionFactoryInitiator.initiateService HHH000399: Using default transaction strategy (direct JDBC transactions)
18-Feb-2016 17:04:53.809 INFO [http-nio-8080-exec-83] org.hibernate.hql.internal.ast.ASTQueryTranslatorFactory.<init> HHH000397: Using ASTQueryTranslatorFactory
Exception : java.time.LocalDate cannot be cast to java.util.Date

Exception : java.time.LocalDate cannot be cast to java.util.Date

18-Feb-2016 17:04:53.049信息[http-nio-8080-exec-83]org.hibernate.cfg.Configuration.addResource hh000221:从资源读取映射：com/newidea/tottracker/mappings/ExamType.hbm.xml
2016年2月18日17:04:53.057信息[http-nio-8080-exec-83]org.hibernate.cfg.Configuration.addResource hh000221:从资源读取映射：com/newidea/tottracker/mappings/Role.hbm.xml
2016年2月18日17:04:53.125信息[http-nio-8080-exec-83]org.hibernate.cfg.Configuration.addResource hh000221:从资源读取映射：com/newidea/tottracker/mappings/Teacher.hbm.xml
2016年2月18日17:04:53.141信息[http-nio-8080-exec-83]org.hibernate.cfg.Configuration.addResource hh000221:从资源读取映射：com/newidea/tottracker/mappings/Course.hbm.xml
2016年2月18日17:04:53.149信息[http-nio-8080-exec-83]org.hibernate.cfg.Configuration.doConfigure HH000041:配置的会话工厂：空
2016年2月18日17:04:53.269信息[http-nio-8080-exec-83]org.hibernate.service.jdbc.connections.internal.driverManager连接ProviderImpl.configure HHH000402:使用hibernate内置连接池（不用于生产！）
2016年2月18日17:04:53.277信息[http-nio-8080-exec-83]org.hibernate.service.jdbc.connections.internal.DriverManagerConnectionProviderImpl.configure hh000115:hibernate连接池大小：20
2016年2月18日17:04:53.277信息[http-nio-8080-exec-83]org.hibernate.service.jdbc.connections.internal.DriverManagerConnectionProviderImpl.configure HHH000006:自动提交模式：false
2016年2月18日17:04:53.277信息[http-nio-8080-exec-83]org.hibernate.service.jdbc.connections.internal.DriverManagerConnectionProviderImpl.configure hh000401:在URL[jdbc:mysql://localhost:3306/sms?zeroDateTimeBehavior=convertToNull]
2016年2月18日17:04:53.277信息[http-nio-8080-exec-83]org.hibernate.service.jdbc.connections.internal.DriverManagerConnectionProviderImpl.configure hh000046:连接属性：{user=root}
2016年2月18日17:04:53.625信息[http-nio-8080-exec-83]org.hibernate.dialogue.dialogue。HH000400:使用方言：org.hibernate.dialogue.mysqldialogue
2016年2月18日17:04:53.801信息[http-nio-8080-exec-83]org.hibernate.engine.transaction.internal.TransactionFactoryInitiator.initiateService HHH000399:使用默认事务策略（直接JDBC事务）
2016年2月18日17:04:53.809信息[http-nio-8080-exec-83]org.hibernate.hql.internal.ast.ASTQueryTranslatorFactory。HH000397:使用ASTQueryTranslatorFactory
异常：java.time.LocalDate不能强制转换为java.util.Date

---

有人能帮我吗？我快疯了！！提前感谢。

似乎有两个不同的错误，其中一个可能是误导性的，是由另一个引起的。正如您在服务器日志中看到的：

18-Feb-2016 17:04:53.049 INFO [http-nio-8080-exec-83] org.hibernate.cfg.Configuration.addResource HHH000221: Reading mappings from resource: com/newidea/tottracker/mappings/ExamType.hbm.xml
18-Feb-2016 17:04:53.057 INFO [http-nio-8080-exec-83] org.hibernate.cfg.Configuration.addResource HHH000221: Reading mappings from resource: com/newidea/tottracker/mappings/Role.hbm.xml
18-Feb-2016 17:04:53.125 INFO [http-nio-8080-exec-83] org.hibernate.cfg.Configuration.addResource HHH000221: Reading mappings from resource: com/newidea/tottracker/mappings/Teacher.hbm.xml
18-Feb-2016 17:04:53.141 INFO [http-nio-8080-exec-83] org.hibernate.cfg.Configuration.addResource HHH000221: Reading mappings from resource: com/newidea/tottracker/mappings/Course.hbm.xml
18-Feb-2016 17:04:53.149 INFO [http-nio-8080-exec-83] org.hibernate.cfg.Configuration.doConfigure HHH000041: Configured SessionFactory: null
18-Feb-2016 17:04:53.269 INFO [http-nio-8080-exec-83] org.hibernate.service.jdbc.connections.internal.DriverManagerConnectionProviderImpl.configure HHH000402: Using Hibernate built-in connection pool (not for production use!)
18-Feb-2016 17:04:53.277 INFO [http-nio-8080-exec-83] org.hibernate.service.jdbc.connections.internal.DriverManagerConnectionProviderImpl.configure HHH000115: Hibernate connection pool size: 20
18-Feb-2016 17:04:53.277 INFO [http-nio-8080-exec-83] org.hibernate.service.jdbc.connections.internal.DriverManagerConnectionProviderImpl.configure HHH000006: Autocommit mode: false
18-Feb-2016 17:04:53.277 INFO [http-nio-8080-exec-83] org.hibernate.service.jdbc.connections.internal.DriverManagerConnectionProviderImpl.configure HHH000401: using driver [com.mysql.jdbc.Driver] at URL [jdbc:mysql://localhost:3306/sms?zeroDateTimeBehavior=convertToNull]
18-Feb-2016 17:04:53.277 INFO [http-nio-8080-exec-83] org.hibernate.service.jdbc.connections.internal.DriverManagerConnectionProviderImpl.configure HHH000046: Connection properties: {user=root}
18-Feb-2016 17:04:53.625 INFO [http-nio-8080-exec-83] org.hibernate.dialect.Dialect.<init> HHH000400: Using dialect: org.hibernate.dialect.MySQLDialect
18-Feb-2016 17:04:53.801 INFO [http-nio-8080-exec-83] org.hibernate.engine.transaction.internal.TransactionFactoryInitiator.initiateService HHH000399: Using default transaction strategy (direct JDBC transactions)
18-Feb-2016 17:04:53.809 INFO [http-nio-8080-exec-83] org.hibernate.hql.internal.ast.ASTQueryTranslatorFactory.<init> HHH000397: Using ASTQueryTranslatorFactory
Exception : java.time.LocalDate cannot be cast to java.util.Date

Exception : java.time.LocalDate cannot be cast to java.util.Date

没有直接转换为旧日期类型。有一种解决方法，但是如果您只是打算使用旧的日期类型，那么您最好更改以下行：

        teacher.setTeacherLastLogin(LocalDateTime.now());

致：

如果坚持使用新的date API，可以将

hibernate-java8

包添加到依赖项中，以直接支持它们。但是，

Instant

类型比LocalDateTime更适合于时间戳

编辑1:

---

NullPointerException是由

action.addTeacher（teacher）

函数返回

null

并试图将其转换为原始值引起的。我认为日期问题是导致服务器日志（无论如何，最后一个日志列表）异常的原因，因此当函数返回时，

TeacherAction.tid

仍然是

null

。

哪一行给出了错误？action.addTeacher（teacher）；在服务器中，我更新了答案。如果您仍然收到NullPointerException，请检查服务器日志，以了解在保存实体失败时下一个错误是什么。我已将该转换添加到LocalDate-to-Date。这似乎没有任何错误。lne动作。addTeacher（teacher）；造成真正的痛苦。