【发布时间】：2021-06-27 09:08:45
【问题描述】：
我在尝试提交创建新员工表单时遇到此错误：
错误：
Hibernate: insert into employee (name, password) values (?, ?)
2021-03-31 17:04:41.395 WARN 1848 --- [nio-8080-exec-5] o.h.engine.jdbc.spi.SqlExceptionHelper : SQL Error: 1364, SQLState: HY000
2021-03-31 17:04:41.395 ERROR 1848 --- [nio-8080-exec-5] o.h.engine.jdbc.spi.SqlExceptionHelper : Field 'useremail' doesn't have a default value
2021-03-31 17:04:41.410 ERROR 1848 --- [nio-8080-exec-5] o.a.c.c.C.[.[.[/].[dispatcherServlet] : Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception [Request processing failed; nested exception is org.springframework.orm.jpa.JpaSystemException: could not execute statement; nested exception is org.hibernate.exception.GenericJDBCException: could not execute statement] with root cause
java.sql.SQLException: Field 'useremail' doesn't have a default value
at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:129) ~[mysql-connector-java-8.0.23.jar:8.0.23]
at com.mysql.cj.jdbc.exceptions.SQLExceptionsMapping.translateException(SQLExceptionsMapping.java:122) ~[mysql-connector-java-8.0.23.jar:8.0.23]
at com.mysql.cj.jdbc.ClientPreparedStatement.executeInternal(ClientPreparedStatement.java:953) ~[mysql-connector-java-8.0.23.jar:8.0.23]
at com.mysql.cj.jdbc.ClientPreparedStatement.executeUpdateInternal(ClientPreparedStatement.java:1092) ~[mysql-connector-java-8.0.23.jar:8.0.23]
at com.mysql.cj.jdbc.ClientPreparedStatement.executeUpdateInternal(ClientPreparedStatement.java:1040) ~[mysql-connector-java-8.0.23.jar:8.0.23]
at com.mysql.cj.jdbc.ClientPreparedStatement.executeLargeUpdate(ClientPreparedStatement.java:1347) ~[mysql-connector-java-8.0.23.jar:8.0.23]
at com.mysql.cj.jdbc.ClientPreparedStatement.executeUpdate(ClientPreparedStatement.java:1025) ~[mysql-connector-java-8.0.23.jar:8.0.23]
at com.zaxxer.hikari.pool.ProxyPreparedStatement.executeUpdate(ProxyPreparedStatement.java:61) ~[HikariCP-3.4.5.jar:na]
at com.zaxxer.hikari.pool.HikariProxyPreparedStatement.executeUpdate(HikariProxyPreparedStatement.java) ~[HikariCP-3.4.5.jar:na]
at org.hibernate.engine.jdbc.internal.ResultSetReturnImpl.executeUpdate(ResultSetReturnImpl.java:197) ~[hibernate-core-5.4.29.Final.jar:5.4.29.Final]
at org.hibernate.dialect.identity.GetGeneratedKeysDelegate.executeAndExtract(GetGeneratedKeysDelegate.java:57) ~[hibernate-core-5.4.29.Final.jar:5.4.29.Final]
at org.hibernate.id.insert.AbstractReturningDelegate.performInsert(AbstractReturningDelegate.java:43) ~[hibernate-core-5.4.29.Final.jar:5.4.29.Final]
at org.hibernate.persister.entity.AbstractEntityPersister.insert(AbstractEntityPersister.java:3195) ~[hibernate-core-5.4.29.Final.jar:5.4.29.Final]
at org.hibernate.persister.entity.AbstractEntityPersister.insert(AbstractEntityPersister.java:3801) ~[hibernate-core-5.4.29.Final.jar:5.4.29.Final]
at org.hibernate.action.internal.EntityIdentityInsertAction.execute(EntityIdentityInsertAction.java:84) ~[hibernate-core-5.4.29.Final.jar:5.4.29.Final]....
有人可以帮我理解为什么会出现这个错误吗？
以下是我的代码：
- 控制器： 以下是员工的控制人
@Controller
public class EmployeeController {
@Autowired
private EmployeeService employeeService;
@RequestMapping("/")
public String viewHomePage(Model model) {
List<Employee> listEmployees = employeeService.listAll();
model.addAttribute("listEmployees" , listEmployees);
return "index";
}
@RequestMapping("/new")
public String showNewProductForm(Model model) {
Employee employee = new Employee();
model.addAttribute("employee" , employee);
return "views/new_employee";
}
@RequestMapping(value ="/save" , method = RequestMethod.POST)
public String saveEmployee(@ModelAttribute("employee") Employee employee) {
System.out.print(employee);
employeeService.save(employee);
return "redirect:/";
}
}
- 型号： 这部分是Employee类部分
@Entity
public class Employee {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
@Column(unique = true)
private String useremail;
private String name;
private String password;
public Employee(String useremail, String name, String password) {
this.useremail = useremail;
this.name = name;
this.password = password;
}
public Employee() {
}
public String getUseremail() {
return useremail;
}
public void setUseremail(String useremail) {
this.useremail = useremail;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getPassword() {
return password;
}
public void setPassword(String password) {
this.password = password;
}
}
- Repository :
这部分是Repository部分
public interface EmployeeRepository extends JpaRepository<Employee, String>{
}
- 服务： 这部分是服务部分
@Service
public class EmployeeService {
@Autowired
private EmployeeRepository employeeRepository;
public List<Employee> listAll() {
return employeeRepository.findAll();
}
public void save(Employee employee) {
employeeRepository.save(employee);
}
public Employee get(String useremail) {
return employeeRepository.findById(useremail).get();
}
public void delete(String useremail) {
employeeRepository.deleteById(useremail);
}
}
- index.html： 此 HTML 部分用于显示员工列表
<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml"
xmlns:th="http://www.thymeleaf.org">
<head>
<meta charset="utf-8"/>
<title>Employee Management</title>
</head>
<body>
<div align="center">
<h1>Product List</h1>
<a href="/new">Create New Employee</a>
<br/><br/>
<table border="1" cellpadding="10">
<thead>
<tr>
<th>Email</th>
<th>Name</th>
<th>Password</th>
<th>Actions</th>
</tr>
</thead>
<tbody>
<tr th:each="employee : ${listEmployees}">
<td th:text="${employee.useremail}">Email</td>
<td th:text="${employee.name}">Name</td>
<td th:text="${employee.password}">Password</td>
</tr>
</tbody>
</table>
</div>
</body>
</html>
- new_employee.html： 这部分是我创建新员工的 HTML
<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml"
xmlns:th="http://www.thymeleaf.org">
<head>
<meta charset="utf-8" />
<title>Create New Employee</title>
</head>
<body>
<div align="center">
<h1>Create New Employee</h1>
<br />
<form action="#" th:action="@{/save}" th:object="${employee}"
method="post">
<table border="0" cellpadding="10">
<tr>
<td>Email:</td>
<td><input type="text" th:field="*{useremail}" /></td>
</tr>
<tr>
<td>Name:</td>
<td><input type="text" th:field="*{name}" /></td>
</tr>
<tr>
<td>Password:</td>
<td><input type="text" th:field="*{password}" /></td>
</tr>
<tr>
<td colspan="2"><button type="submit">Save</button> </td>
</tr>
</table>
</form>
</div>
</body>
</html>
数据库图像：
【问题讨论】：
-
该字段在 SQL 中是否有默认值？也许这和this question 中的问题相同...如果在这里看到 SQL 就好了。
-
您好，感谢您的回复，该字段（useremail）没有默认值，因为它是主键
-
"有人能帮我理解为什么会出现这个错误吗？"是的。发生这种情况是因为“字段'useremail'没有默认值”。您需要在
insert声明中提供它。 -
对于主键的情况，您可能需要削弱一些配置限制（从该表中删除要求默认值或一般禁用它）。见this post
-
显示您的 DDL。看起来休眠期望数据库将填充主键，但数据库不这样做。