detached entity passed to persist

http://blog.csdn.net/moliqin/article/details/6725643
http://dl.vmall.com/c0fq73hzf7

描述 :使用spring+strust2配置，第一次新增成功，第二次新增抛异常

HTTP Status 500 -
type Exception report
message
description The server encountered an internal error () that prevented it from fulfilling this request.
exception
org.springframework.dao.InvalidDataAccessApiUsageException: detached entity passed to persist: model.Product; nested exception is org.hibernate.PersistentObjectException: detached entity passed to persist: model.Product
    org.springframework.orm.hibernate3.SessionFactoryUtils.convertHibernateAccessException(SessionFactoryUtils.java:648)
    org.springframework.orm.jpa.vendor.HibernateJpaDialect.translateExceptionIfPossible(HibernateJpaDialect.java:95)
    org.springframework.dao.support.DataAccessUtils.translateIfNecessary(DataAccessUtils.java:212)
    org.springframework.orm.jpa.JpaAccessor.translateIfNecessary(JpaAccessor.java:152)
    org.springframework.orm.jpa.JpaTemplate.execute(JpaTemplate.java:189)
    org.springframework.orm.jpa.JpaTemplate.persist(JpaTemplate.java:266)
root cause
org.hibernate.PersistentObjectException: detached entity passed to persist: model.Product
note The full stack trace of the root cause is available in the Apache Tomcat/6.0.26 logs.
Apache Tomcat/6.0.26

 

方案一 (推荐)

设置spring配置文件，使每次请求都重新初始化变量

    <bean id="demoAction" class="com.web.action.DemoAction" scope="prototype"></bean>

方案二

在新增的Jsp页面隐藏对应的ID字段，使其值为零

<input type="hidden" name="bean.id" value="0" />

方案三

在执行方法体内，对刚刚持久化的实体手工初始化

public String  execute throw Exception {

      demoService.addBean(bean);
      DemoBean = new DemoBean ();

}

另 如果 action在单实例时，只要程序异常，是无法再次执行，推荐Action使用 scope="prototype"

 

HTTP Status 404 - No result defined for action com.web.action.DemoAction and result input

---

 

type Status report

message No result defined for action com.web.action.DemoAction and result input

description The requested resource (No result defined for action com.web.action.DemoAction and result input) is not available.