Spring JDBC事务管理器 [英] Spring JDBC transaction manager

问题描述

我尝试在Spring中使用JDBC编写事务管理器。

I try to write a transaction manager using JDBC in Spring.

我的app-servlet.xml

my app-servlet.xml

<!-- JDBC Config -->
<bean   id="dataSource" 
        class="org.apache.commons.dbcp.BasicDataSource"
        destroy-method="close" 
        p:driverClassName="${jdbc.driverClassName}"
        p:url="${jdbc.databaseurl}" 
        p:username="${jdbc.username}" 
        p:password="${jdbc.password}" />

<!-- dataSource TransactionManager -->
<bean id="transactionManager"
    class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
    <property name="dataSource" ref="dataSource" />
</bean>

<bean id="UserDAOImpl" class="com.project.dao.impl.UserDAOImpl">
    <property name="transactionManager" ref="transactionManager"/>
</bean>

我的UserDAOImpl.java

my UserDAOImpl.java

public class UserDAOImpl implements UserDAO {

//transaction manager
private DataSourceTransactionManager transactionManager;
private JdbcTemplate jdbcTemplate;

public UserDAOImpl() {
    super();
    DataSource dataSource = transactionManager.getDataSource();
    jdbcTemplate = new JdbcTemplate(dataSource);
}

public void setTransactionManager(DataSourceTransactionManager transactionManager)    {
    this.transactionManager = transactionManager;
}
....
}

即使我有$ code> transactionManager 我的app-servlet中的Bean， UserDAOImpl 将不会被实例化，因为 transactionManager 是 null 。可能我错过了一些观点，但无法找出问题所在。

Even though I have transactionManager Bean in my app-servlet, UserDAOImpl won't be instatiated because transactionManager is null. Probably I miss some point but couldn't find out what is wrong.

推荐答案

您应该为事务管理器使用构造函数注入。 Spring会在它注入transactionManager属性之前调用构造函数。

You should use constructor injection for your transaction manager. Spring is going to call the constructor before it can inject the transactionManager property.

 public UserDAOImpl() 
 {
    /* Transaction Manager NOT set yet */
    DataSource dataSource = transactionManager.getDataSource();
 }

更改它以使用构造函数注入

Change it to use constructor injection

 public UserDAOImpl(TransactionManager transactionManager) ...

然后配置

 <bean id="UserDAOImpl" class="com.project.dao.impl.UserDAOImpl">
   <constructor-arg ref="transactionManager"/>
 </bean>

这篇关于Spring JDBC事务管理器的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！