关于在测试类中，懒加载问题导致加载了主类之后，在测试类中引用集合类出现错误的问题

来源：互联网发布：t6软件是什么编辑：程序博客网时间：2024/06/05 15:44

关于在测试类中，懒加载问题导致加载了主类之后，在测试类中引用集合类出现错误的问题：
主要原因是因为：hibernate的事物是给了spring管理，而测试类中写的代码，是不归spring管理的，把代码转移到service中去执行进行

在测试类：EmployeeServiceTest中直接运行

    @Test    public void testEmployeeInDept(){        try {            Department department = DepartMentService.getDepartmentByName("ixin开发部");            Set<Employee> set = department.getEmps();            for (Employee employee : set) {                System.out.println(employee.getName());            }        } catch (Exception e) {            // TODO: handle exception            e.printStackTrace();        }    }

出现错误：

    /**     * 因为在测试代码中，事物是不归spring管理的，所以执行:     * Department department = DepartMentService.getDepartmentByName("ixin开发部");     *  的时候，还是有事物的，处于spring管理的事物范围之内，而执行完成之后，就断了。     * 所以在：Set<Employee> set = department.getEmps();这个执行代码中，是获取不到内容的     * 会报异常：     * Hibernate:     select        department0_.id as id1_0_,        department0_.name as name2_0_     from        department department0_     where        department0_.name=?org.hibernate.LazyInitializationException: failed to lazily initialize a collection of role: com.xltx.productinfograb.domain.entity.Department.emps, could not initialize proxy - no Session     */

import java.io.Serializable;import java.util.HashSet;import java.util.Set;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.Table;@Entity@Table(name = "department")public class Department implements Serializable{    private Long id;    private String name;    private Set<Employee> emps = new HashSet<>();    @Id    @GeneratedValue(strategy = GenerationType.AUTO)    public Long getId() {        return id;    }    public void setId(Long id) {        this.id = id;    }    @Column(name = "name", length = 20)    public String getName() {        return name;    }    public void setName(String name) {        this.name = name;    }    /**     * 总结：mappedBy属性跟xml配置文件里的inverse一样。在一对多或一对一的关系映射中，如果不表明mappedBy属性，默认是由本方维护外键。但如果两方都由本方来维护的话，会多出一些update语句，性能有一定的损耗。解决的办法就是在一的一方配置上mappedBy属性，将维护权交给多的一方来维护，就不会有update语句了。至于为何要将维护权交给多的一方，可以这样考虑：要想一个国家的领导人记住所有人民的名字是不可能的，但可以让所有人民记住领导人的名字！注意，配了mappedBy属性后，不要再有@JoinColumn，会冲突！     * @return     */    @OneToMany(fetch = FetchType.LAZY, mappedBy = "dept")    public Set<Employee> getEmps() {        return emps;    }    public void setEmps(Set<Employee> emps) {        this.emps = emps;    }    @Override    public String toString() {        return "Department [id=" + id + ", name=" + name + ", emps=" + emps                + "]";    }    public Department() {        super();        // TODO Auto-generated constructor stub    }}

import java.io.Serializable;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.Table;@Entity@Table(name = "employee")public class Employee implements Serializable{    private Long id;    private String name;    private float salary;    private String email;    private Department dept;    public Employee() {        super();        // TODO Auto-generated constructor stub    }    @Override    public String toString() {        return "Employee [id=" + id + ", name=" + name + ", salary=" + salary                + ", email=" + email + ", dept=" + dept + "]";    }    @Id    @GeneratedValue(strategy = GenerationType.AUTO)    public Long getId() {        return id;    }    public void setId(Long id) {        this.id = id;    }    @Column(name = "name", length = 30)    public String getName() {        return name;    }    public void setName(String name) {        this.name = name;    }    @Column(name = "salary")    public float getSalary() {        return salary;    }    public void setSalary(float salary) {        this.salary = salary;    }    @Column(name = "email", length = 30)    public String getEmail() {        return email;    }    public void setEmail(String email) {        this.email = email;    }    @ManyToOne(fetch = FetchType.LAZY)    @JoinColumn(name = "dept", nullable = false)    public Department getDept() {        return dept;    }    public void setDept(Department dept) {        this.dept = dept;    }}

import java.io.Serializable;import java.util.Set;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.stereotype.Service;import org.springframework.transaction.annotation.Transactional;import com.xltx.orm.dao.BaseDao;import com.xltx.productinfograb.domain.entity.Department;import com.xltx.productinfograb.domain.entity.Employee;@Service@Transactional(readOnly = false, rollbackFor = Exception.class)public class DepartMentService {    @Autowired    BaseDao baseDao;    public Department add(Department department){        Serializable id = baseDao.add(department);        department = baseDao.get(Department.class, id);        return department;    }    public Department getDepartmentByName(String departmentName){        String hql = "From Department d where d.name = ?";        Department department = baseDao.getFirstByHql(hql, departmentName);        return department;    }    public void testEmployeeInDept(){        Department department = getDepartmentByName("xxx开发部");        Set<Employee> set = department.getEmps();        for (Employee employee : set) {            System.out.println(employee.getName());        }    }}

package com.xltx.test;import java.util.Set;import org.junit.Test;import org.junit.runner.RunWith;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.test.context.ContextConfiguration;import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;import com.xltx.productinfograb.domain.entity.Department;import com.xltx.productinfograb.domain.entity.Employee;import com.xltx.productinfograb.service.impl.DepartMentService;import com.xltx.productinfograb.service.impl.EmployeeService;@RunWith(SpringJUnit4ClassRunner.class)  //使用junit4进行测试  @ContextConfiguration({"classpath:applicationContext.xml"}) //加载配置文件public class EmployeeServiceTest {    @Autowired    EmployeeService employeeService;    @Autowired    DepartMentService DepartMentService;    @Test    public void add(){        Department dept = DepartMentService.getDepartmentByName("ixin开发部");        Employee employee = new Employee();        employee.setDept(dept);        employee.setEmail("13076684@qq.com");        employee.setName("何冠宏");        employee.setSalary(100000.00f);        employeeService.add(employee);        Employee employee2 = new Employee();        employee2.setDept(dept);        employee2.setEmail("111@qq.com");        employee2.setName("22何冠宏");        employee2.setSalary(200000.00f);        employeeService.add(employee2);        Employee employee3 = new Employee();        employee3.setDept(dept);        employee3.setEmail("33@qq.com");        employee3.setName("33何冠宏");        employee3.setSalary(300000.00f);        employeeService.add(employee3);    }    /**     * 因为在测试代码中，事物是不归spring管理的，所以执行:     * Department department = DepartMentService.getDepartmentByName("ixin开发部");     * 的时候，还是有事物的，处于spring管理的事物范围之内，而执行完成之后，就断了。     * 所以在：Set<Employee> set = department.getEmps();这个执行代码中，是获取不到内容的     * 会报异常：     * Hibernate:     select        department0_.id as id1_0_,        department0_.name as name2_0_     from        department department0_     where        department0_.name=?org.hibernate.LazyInitializationException: failed to lazily initialize a collection of role: com.xltx.productinfograb.domain.entity.Department.emps, could not initialize proxy - no Session     */    @Test    public void testEmployeeInDept(){        try {            Department department = DepartMentService.getDepartmentByName("ixin开发部");            Set<Employee> set = department.getEmps();            for (Employee employee : set) {                System.out.println(employee.getName());            }        } catch (Exception e) {            // TODO: handle exception            e.printStackTrace();        }    }    /**     * 将代码放到处于spring管理的service中去执行之后，就不会有问题了     */    @Test    public void test1(){        try {            DepartMentService.testEmployeeInDept();            System.out.println("");        } catch (Exception e) {            // TODO: handle exception            e.printStackTrace();        }    }}

阅读全文

0 0