Java 使用OpenJPA时事务未处于活动状态
我的servlet有一个令人沮丧的问题。这是非常基本的，我应该在数据库表中添加一个blog条目，该表有3列（id、tittel（title）、main（mainbody））。我可以从数据库加载并显示在jsp文件中。然而，我无法将数据持久化到数据库中，我也不知道为什么 我使用postgres作为数据库 这是我的“saveBlog”-方法：Java 使用OpenJPA时事务未处于活动状态,java,postgresql,servlets,jpa,openjpa,Java,Postgresql,Servlets,Jpa,Openjpa,我的servlet有一个令人沮丧的问题。这是非常基本的，我应该在数据库表中添加一个blog条目，该表有3列（id、tittel（title）、main（mainbody））。我可以从数据库加载并显示在jsp文件中。然而，我无法将数据持久化到数据库中，我也不知道为什么 我使用postgres作为数据库 这是我的“saveBlog”-方法： public void lagreBlogg(Blogg b){ EntityManager em = Persistence.
public void lagreBlogg(Blogg b){
EntityManager em = Persistence.createEntityManagerFactory("kimsBlogg").createEntityManager();
EntityTransaction transaction = em.getTransaction();
try {
transaction.begin();
em.persist(b);
transaction.commit();
} catch (Exception e) {
transaction.rollback();
} finally {
em.close();
}
}
}
@Entity
@Table(schema = "blogg", name = "blogg")
public class Blogg {
@Id
@GeneratedValue
private int id;
private String tittel;
private String main;
public Blogg() {
}
public Blogg(String tittel, String main){
this.tittel= tittel;
this.main = main;
}
public String getTittel() {
return tittel;
}
public void setTittel(String tittel) {
this.tittel = tittel;
}
public String getMain() {
return main;
}
public void setMain(String main) {
this.main = main;
}
}
public void lagreBlogg(Blogg b){
EntityManager em = Persistence.createEntityManagerFactory("kimsBlogg").createEntityManager();
EntityTransaction transaction = em.getTransaction();
try {
transaction.begin();
em.persist(b);
transaction.commit();
} catch (Exception e) {
transaction.rollback();
} finally {
em.close();
}
}
}
@Entity
@Table(schema = "blogg", name = "blogg")
public class Blogg {
@Id
@GeneratedValue
private int id;
private String tittel;
private String main;
public Blogg() {
}
public Blogg(String tittel, String main){
this.tittel= tittel;
this.main = main;
}
public String getTittel() {
return tittel;
}
public void setTittel(String tittel) {
this.tittel = tittel;
}
public String getMain() {
return main;
}
public void setMain(String main) {
this.main = main;
}
}
<?xml version="1.0" encoding="UTF-8" ?>
<persistence xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/persistence http://java.sun.com/xml/ns/persistence/persistence_2_0.xsd"
version="2.0" xmlns="http://java.sun.com/xml/ns/persistence">
<persistence-unit name="kimsBlogg">
<provider>org.apache.openjpa.persistence.PersistenceProviderImpl
</provider>
<class>no.kim.model.Blogg</class>
<properties>
<property name="javax.persistence.jdbc.logging.level" value="INFO" />
<property name="javax.persistence.jdbc.driver" value="org.postgresql.Driver" />
<property name="javax.persistence.jdbc.url" value="jdbc:postgresql://localhost:5432/postgres" />
<property name="javax.persistence.jdbc.user" value="postgres" />
<property name="javax.persistence.jdbc.password" value="krheggen" />
<property name="openjpa.RuntimeUnenhancedClasses" value="supported" />
</properties>
</persistence-unit>
org.apache.openjpa.persistence.PersistenceProviderImpl
不，kim.model.Blogg
public void lagreBlogg(Blogg b){
EntityManager em = Persistence.createEntityManagerFactory("kimsBlogg").createEntityManager();
EntityTransaction transaction = em.getTransaction();
try {
transaction.begin();
em.persist(b);
transaction.commit();
} catch (Exception e) {
transaction.rollback();
} finally {
em.close();
}
}
}
@Entity
@Table(schema = "blogg", name = "blogg")
public class Blogg {
@Id
@GeneratedValue
private int id;
private String tittel;
private String main;
public Blogg() {
}
public Blogg(String tittel, String main){
this.tittel= tittel;
this.main = main;
}
public String getTittel() {
return tittel;
}
public void setTittel(String tittel) {
this.tittel = tittel;
}
public String getMain() {
return main;
}
public void setMain(String main) {
this.main = main;
}
}
“transaction.rollback（）；”这似乎很简单，只需为表
bloggcatch（）