Question

我在这里做错了什么？我收到这个错误...

无法将java.lang.String类型的属性值转换为属性部门所需的com.akybenko.entity.Department类型;嵌套异常是java.lang.IllegalStateException：无法将java.lang.String类型的值转换为必需类型com.akybenko.entity.Department for property department：找不到匹配的编辑器或转换策略

请帮我解决这个问题。

EmployeeController.java

package com.akybenko.controller;

import java.beans.PropertyEditorSupport;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.validation.BindingResult;
import org.springframework.validation.annotation.Validated;
import org.springframework.web.bind.ServletRequestDataBinder;
import org.springframework.web.bind.WebDataBinder;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.InitBinder;
import org.springframework.web.bind.annotation.ModelAttribute;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;

import com.akybenko.entity.Department;
import com.akybenko.entity.Employee;
import com.akybenko.service.DepartmentService;
import com.akybenko.service.EmployeeService;

@Controller
@RequestMapping("/employee")
public class EmployeeController {

    @Autowired
    private EmployeeService employeeService;

    @Autowired
    private DepartmentService departmentService;

    class EmployeeEditor extends PropertyEditorSupport {
        @Override
        public void setAsText(String text) throws IllegalArgumentException {
            int id = Integer.parseInt(text);
            Employee employee = employeeService.get(id);
            setValue(employee);
        }
    }

    @InitBinder
    protected void initBinder(HttpServletRequest request, ServletRequestDataBinder binder) {
        binder.registerCustomEditor(Employee.class, new EmployeeEditor());
    }

    @GetMapping("/list")
    public String listEmployees(Model model) {
        List<Employee> employees = employeeService.getAll();
        model.addAttribute("employees", employees);
        return "list-employees";
    }

    @GetMapping("/add")
    public String getAddEmployee(Model model) {
        model.addAttribute("addEmployee", new Employee());
        model.addAttribute("listDept", departmentService.getAll());

        return "addEmployee";
    }

    @PostMapping("/add")
    public String add(
            @ModelAttribute("addEmployee") Employee employee, 
            BindingResult result, 
            Model model) {
        if (result.hasErrors()) {
            return "addEmployee";
        }
        employeeService.add(employee);
        return "redirect:/employee/list";
    }
}

addEmployee.jsp

<%@ taglib uri="http://www.springframework.org/tags/form" prefix="form" %>
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>
<%@ taglib uri="http://www.springframework.org/tags" prefix="spring" %>
<%@ page import="com.akybenko.entity.Department" %>

<!DOCTYPE html>
<html>
    <head>
        <title>Add Employee</title>
        <link rel="stylesheet" type="text/css" href="${pageContext.request.contextPath}/resources/css/addEmployee.css" />
    </head>

    <body>
        <div id = "wrapper">
            <div id = "header">
                <h2>ADD EMPLOYEE</h2>
            </div>
        </div>
        <div id = "container">
            <form:form action="add" modelAttribute="addEmployee" method="post">
                <div class="row">
                    <label for="employeeId">ID</label>
                    <div>
                        <form:input path="employeeId"/>
                    </div>
                </div>          
                <div class="row">
                    <div>
                        <label for="employeeLastName">Last Name</label>
                        <div>
                            <form:input path="employeeLastName"/>
                        </div>
                    </div>
                </div>
                <div class="row">
                    <div>
                        <label for="employeeFirstName">First Name</label>
                        <div>
                            <form:input path="employeeFirstName"/>
                        </div>
                    </div>
                </div>
                <div class="row">
                    <div>
                        <label for="department">Department</label>
                        <div>
                            <form:select path="department">
                                <form:option value="NONE">---SELECT---</form:option>
                                <form:options items="${listDept}" itemLabel="departmentName" itemValue="departmentId" />
                            </form:select>
                        </div>
                        <div>
                            <form:errors path="department" />
                        </div>
                    </div>
                </div>

                <div><input type="submit" value="Save" id="buttonSave"/> </div>
                <div><input type="reset" value="Reset" id="buttonReset"/></div>
            </form:form>
        </div>
    </body>
</html>

Employee.java

package com.akybenko.entity;

import java.io.Serializable;

import javax.persistence.CascadeType;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.FetchType;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.ManyToOne;
import javax.persistence.SequenceGenerator;
import javax.persistence.Table;

@Entity
@Table(name="employee")
public class Employee implements Serializable {

    private static final long serialVersionUID = 1L;

    @Id
    @GeneratedValue(strategy=GenerationType.SEQUENCE, generator="EMP_SEQUENCE")
    @SequenceGenerator(name="EMP_SEQUENCE", sequenceName="employee_seq", allocationSize=1)
    @Column(name="employee_id")
    private int employeeId;

    @Column(name="employee_lname")
    private String employeeLastName;

    @Column(name="employee_fname")
    private String employeeFirstName;

    @ManyToOne(cascade=CascadeType.ALL, fetch=FetchType.EAGER)
    @JoinColumn(name="department_id", referencedColumnName="department_id", nullable = false, insertable = false, updatable = false)
    private Department department;

    public int getEmployeeId() {
        return employeeId;
    }

    public void setEmployeeId(int employeeId) {
        this.employeeId = employeeId;
    }

    public String getEmployeeLastName() {
        return employeeLastName;
    }

    public void setEmployeeLastName(String employeeLastName) {
        this.employeeLastName = employeeLastName;
    }

    public String getEmployeeFirstName() {
        return employeeFirstName;
    }

    public void setEmployeeFirstName(String employeeFirstName) {
        this.employeeFirstName = employeeFirstName;
    }

    public Department getDepartment() {
        return department;
    }

    public void setDepartment(Department department) {
        this.department = department;
    }

    @Override
    public String toString() {
        return "Employee [employeeId=" + employeeId + ", employeeLastName=" + employeeLastName + ", employeeFirstName="
                + employeeFirstName + ", department=" + department + "]";
    }
}

Department.java

package com.akybenko.entity;

import java.io.Serializable;
import java.util.List;

import javax.persistence.CascadeType;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.FetchType;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.OneToMany;
import javax.persistence.SequenceGenerator;
import javax.persistence.Table;

@Entity
@Table(name="department")
public class Department implements Serializable {

    private static final long serialVersionUID = 1L;

    @Id
    @GeneratedValue(strategy=GenerationType.SEQUENCE, generator="DEPT_SEQUENCE")
    @SequenceGenerator(name="DEPT_SEQUENCE", sequenceName="department_seq", allocationSize=1)
    @Column(name="department_id")
    private int departmentId;

    @Column(name="department_name")
    private String departmentName;

    @OneToMany(mappedBy="department", cascade=CascadeType.ALL, fetch=FetchType.EAGER)
    private List<Employee> employees;

    public int getDepartmentId() {
        return departmentId;
    }

    public void setDepartmentId(int departmentId) {
        this.departmentId = departmentId;
    }

    public String getDepartmentName() {
        return departmentName;
    }

    public void setDepartmentName(String departmentName) {
        this.departmentName = departmentName;
    }

    public List<Employee> getEmployees() {
        return employees;
    }

    public void setEmployees(List<Employee> employees) {
        this.employees = employees;
    }

    @Override
    public String toString() {
        return "Department [departmentId=" + departmentId + ", departmentName=" + departmentName + ", employees="
                + employees + "]";
    }
}

Answer 1

我在这里做错了什么？

Department是参考表。最好从中移除employees。

请添加课程DepartmentDto，EmployeeDto并在网络上使用它们。

在EmployeeService#add()方法中：

从departmentId获取EmployeeDto。
如果没有可以转换为404 HTTP错误的部门生成异常，请检查数据库中是否存在departmentId部门。
将EmployeeDto转换为Employee并将Department设置为Employee（您可以使用load()方法，或者创建一个假的部门仅departmentId。

无法将类型为java.lang.String的属性值转换为属性部门所需的类型com.akybenko.entity.Department;

1 个答案: