Hibernate异常之 org.hibernate.LazyInitializationException: failed to lazily initialize a collecio....

1、异常描述

 org.hibernate.LazyInitializationException: 
 failed to lazily initialize a collection of role: cn.wang.entity.Clazz.studentSet, no session or session was closed

备注：

      此处hibernate版本号：3.6.10.Final

 

2、示例代码

2-1 实体类

// 学生实体类
public class Student  implements Serializable{
	private Integer id;
	private String name;
	private Date birthday;

	// 创建关系属性
	private Clazz clazz;
        // 省略相关代码...
	
}

// 班级表
public class Clazz implements Serializable{
	private Integer id;
	private String name;
	
	// 建立关系属性
	private Set<Student> studentSet = new HashSet<>();
	
    // 省略部分代码...

 

2-2 Clazz.hbm.xml

<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC 
    "-//Hibernat