利用 JdbcTemplate 自动返回 MS SQL SERVER 2005 自增主键值
JDBC3 中可以直接获取当前插入记录的 ID 值，具体的调用方式如下：
Statement stmt
=
conn.createStatement();stmt.executeUpdate(
"
INSERT INTO authors (first_name, last_name) values(′George′, ′Orwell′) " , Statement.RETURN_GENERATED_KEYS);
ResultSet rs
=
stmt.getGeneratedKeys();
if
( rs.next() )
...
{
int key = rs.getInt();
}
由于实际与数据库交互采用的是 JdbcTemplate，因而需要找到它对这种方式的支持。经过实际的查看 Spring 的 API 发现其本身提供相应的方法支持，经过多次的实验后得到如下的实现方法：
private
void
insert(
final
Profile profile)
...
{ final String _save = "insert into Newsletter_Profile (user_id, publication_id, last_update) values (?, ?, getdate())"; JdbcTemplate template = this.getJdbcTemplate(); KeyHolder keyHolder = new GeneratedKeyHolder();
template.update(new PreparedStatementCreator() ...{ public PreparedStatement createPreparedStatement(Connection con) throws SQLException ...{ int i = 0; PreparedStatement ps = con.prepareStatement(_save, Statement.RETURN_GENERATED_KEYS); ps.setInt(++i, profile.getCustomerId().intValue()); ps.setInt(++i, profile.getPublication().getId()); return ps;
} }, keyHolder); profile.setId(keyHolder.getKey().intValue()); }
特别需要注意的地方是 Statement.RETURN_GENERATED_KEYS，在使用MS SQL Server 2005 提供的 JDBC Driver 中上面的部分是必须的。之所以这么说是因为 google 出来的所有资料都是没有该部分的，甚至 Spring 自身的 document 中也是没有该参数的。我现在不知道那些代码是否能够真正的获取到 Key，但是现在我 suppose 它们是可以 run 的。
如果没有加入 Statement.RETURN_GENERATED_KEYS ，在实际进行数据库操作时会出现如下的异常：
PreparedStatementCallback; uncategorized SQLException for SQL []; SQL state [null]; error code [0]; The statement must be executed before any results can be obtained.; nested exception is com.microsoft.sqlserver.jdbc.SQLServerException: The statement must be executed before any results can be obtained.
caused by : com.microsoft.sqlserver.jdbc.SQLServerException: The statement must be executed before any results can be obtained.
org.springframework.jdbc.UncategorizedSQLException: PreparedStatementCallback; uncategorized SQLException for SQL []; SQL state [null]; error code [0]; The statement must be executed before any results can be obtained.; nested exception is com.microsoft.sqlserver.jdbc.SQLServerException: The statement must be executed before any results can be obtained.
Caused by: com.microsoft.sqlserver.jdbc.SQLServerException: The statement must be executed before any results can be obtained.
at com.microsoft.sqlserver.jdbc.SQLServerException.makeFromDriverError(Unknown Source)
at com.microsoft.sqlserver.jdbc.SQLServerStatement.getGeneratedKeys(Unknown Source)
at weblogic.jdbc.wrapper.PreparedStatement_com_microsoft_sqlserver_jdbc_SQLServerPreparedStatement.getGeneratedKeys(Unknown Source)
at org.springframework.jdbc.core.JdbcTemplate$3.doInPreparedStatement(JdbcTemplate.java:772)
at org.springframework.jdbc.core.JdbcTemplate.execute(JdbcTemplate.java:527)
at org.springframework.jdbc.core.JdbcTemplate.update(JdbcTemplate.java:767)
at com.fdc.reports20.dao.NewsletterDAO.insert(NewsletterDAO.java:179)
at com.fdc.reports20.dao.NewsletterDAO.save(NewsletterDAO.java:153)
at com.fdc.reports20.dao.NewsletterDAO.update(NewsletterDAO.java:138)
at com.fdc.reports20.business.service.user.AlertServiceImpl.updateNewsletter(AlertServiceImpl.java:146)
at com.fdc.reports20.business.service.user.AlertServiceImpl$$FastClassByCGLIB$$52b80fbc.invoke()
at net.sf.cglib.proxy.MethodProxy.invoke(MethodProxy.java:149)
at org.springframework.aop.framework.Cglib2AopProxy$CglibMethodInvocation.invokeJoinpoint(Cglib2AopProxy.java:674)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:154)
at org.springframework.aop.aspectj.AspectJAfterThrowingAdvice.invoke(AspectJAfterThrowingAdvice.java:52)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:176)
at org.springframework.aop.framework.adapter.MethodBeforeAdviceInterceptor.invoke(MethodBeforeAdviceInterceptor.java:53)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:176)
at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:107)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:176)
at org.springframework.aop.interceptor.ExposeInvocationInterceptor.invoke(ExposeInvocationInterceptor.java:89)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:176)
at org.springframework.aop.framework.Cglib2AopProxy$DynamicAdvisedInterceptor.intercept(Cglib2AopProxy.java:615)
at com.fdc.reports20.business.service.user.AlertServiceImpl$$EnhancerByCGLIB$$a12ee5d8.updateNewsletter()
at com.fdc.reports20.web.delegate.AlertBD.updateNewsletter(AlertBD.java:78)
at com.fdc.reports20.web.jpf.um.workbench.WorkBenchController.editPublicationEmails(WorkBenchController.java:149)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)