java - MyBatis 插入 null 时出现 nullPointerException

Question

当我尝试插入一条主键为空的记录，然后取回键值(oracle 触发器设置键)时，我得到了 MyBatis NPE。

FooMapper接口(interface):

...
public void insertFooObject (final Foo foo);
...

FooMapper.xml:

...
    <insert id="insertFooObject" useGeneratedKeys="true" keyColumn="foo_id" keyProperty="fooId">
        insert into foos (foo_id, gcor_id, registration_date)
        values (#{fooId, jdbcType=NUMERIC}, #{gcorId, jdbcType=NUMERIC}, #{registrationDate, jdbcType=DATE})
    </insert>  
...

这是模型:

public class Foo {
    private final Integer fooId;
    private final Integer gcorId;
    private final Date registrationDate;

    public Foo(final Integer fooId, final Integer gcorId, final Date registrationDate)     {
        this.fooId = fooId;
        this.gcorId = gcorId;
        this.registrationDate = registrationDate;
    }
...

电话如下:

... 
Foo foo = new Foo(null, 229, null);
fooMapper.insertFooObject(foo);
...

fooMapper由spring注入(inject)，可以成功用于其他SQL语句。当我传入 fooId 的数字且 RegistrationDate 为 null 时，一切正常。当 fooId 为 null 时(如图所示)，我收到错误:

org.mybatis.spring.MyBatisSystemException: nested exception is org.apache.ibatis.exceptions.PersistenceException: 
 Error updating database.  Cause: java.lang.NullPointerException
 The error may involve defaultParameterMap
 The error occurred while setting parameters
 SQL: insert into foos (foo_id, gcor_id, registration_date)         values (?, ?, ?)
 Cause: java.lang.NullPointerException

这是我的配置文件:

<?xml version="1.0" encoding="UTF-8"?>
<beans
    xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns:util="http://www.springframework.org/schema/util"
    xsi:schemaLocation="
        http://www.springframework.org/schema/beans
        http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
        http://www.springframework.org/schema/util
        http://www.springframework.org/schema/util/spring-util-3.0.xsd
    ">

    <bean id="datasource" class="org.apache.ibatis.datasource.pooled.PooledDataSource">
        <property name="driver" value="oracle.jdbc.driver.OracleDriver"/>        
        <property name="url" value="jdbc:oracle:thin:@......"/>
        <property name="username" value="..."/>
        <property name="password" value="..."/>
    </bean>

    <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
        <property name="dataSource" ref="datasource"/>
    </bean>

    <bean id="fooMapper" class="org.mybatis.spring.mapper.MapperFactoryBean">
        <property name="mapperInterface" value="com.foo.FooMapper" />
        <property name="sqlSessionFactory" ref="sqlSessionFactory" />
    </bean>

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

有什么想法可以纠正这个问题吗？我没有运气谷歌搜索，并认为通过指定 jdbcType 就可以了。谢谢!

Answer 1

我相信您正在为 Oracle 使用 useGeneeratedkeys，而 Oracle 不支持该功能。我相信 mysql 和 postgress 支持 generatedKeys。而是使用 selectkeys 来获取下一个值，或者当您可以将 null 值传递给 fooId 时，删除默认为 false 的 useGeneeratedKeys 。您可以使用序列获取下一个值

<selectKey keyProperty="fooId"
             resultClass="int">
    SELECT nextVal('foo_id_seq')
 </selectKey>