博客

错误产生的场景

• dao层接口如下

int getResourceDataNumsByTitle(String title);

• mapper.xml 中sql语句如下

<select id="getResourceDataNumsByTitle" parameterType="java.lang.String" resultType="java.lang.Integer">
        SELECT * FROM t_resourceData where title = #{title}
</select>

• Service层

for(ResourceData r : resourceDatas){
                if(!(getResourceDataNumsByTitle(r.getTitle()) > 0)){
                    resourceMapper.insertOneResourceData(r);
                    LOG.info(r.getTitle()+"已插入");
     }
}

• 报错如下

org.apache.ibatis.binding.BindingException: Mapper method 'com.haoeasy.news.mapper.ResourceMapper.getResourceDataNumsByTitle attempted 
to return null from a method with a primitive return type (int).
	at org.apache.ibatis.binding.MapperMethod.execute(MapperMethod.java:93)
	at org.apache.ibatis.binding.MapperProxy.invoke(MapperProxy.java:59)
	at com.sun.proxy.$Proxy71.getResourceDataNumsByTitle(Unknown Source)
	at com.haoeasy.news.serviceimpl.ResourceServiceImpl.getResourceDataNumsByTitle(ResourceServiceImpl.java:39)
	at com.haoeasy.news.serviceimpl.ResourceServiceImpl.insertOneResourceData(ResourceServiceImpl.java:23)
	at com.haoeasy.news.news.NewsApplicationTests.getUrlContent(NewsApplicationTests.java:105)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:498)
	at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)
	at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
	at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)
	at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
	at org.springframework.test.context.junit4.statements.RunBeforeTestExecutionCallbacks.evaluate(RunBeforeTestExecutionCallbacks.java:74)
	at org.springframework.test.context.junit4.statements.RunAfterTestExecutionCallbacks.evaluate(RunAfterTestExecutionCallbacks.java:84)
	at org.springframework.test.context.junit4.statements.RunBeforeTestMethodCallbacks.evaluate(RunBeforeTestMethodCallbacks.java:75)
	at org.springframework.test.context.junit4.statements.RunAfterTestMethodCallbacks.evaluate(RunAfterTestMethodCallbacks.java:86)
	at org.springframework.test.context.junit4.statements.SpringRepeat.evaluate(SpringRepeat.java:84)
	at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)
	at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:251)
	at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:97)
	at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
	at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
	at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
	at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
	at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
	at org.springframework.test.context.junit4.statements.RunBeforeTestClassCallbacks.evaluate(RunBeforeTestClassCallbacks.java:61)
	at org.springframework.test.context.junit4.statements.RunAfterTestClassCallbacks.evaluate(RunAfterTestClassCallbacks.java:70)
	at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
	at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.run(SpringJUnit4ClassRunner.java:190)
	at org.junit.runner.JUnitCore.run(JUnitCore.java:137)
	at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:68)
	at com.intellij.rt.execution.junit.IdeaTestRunner$Repeater.startRunnerWithArgs(IdeaTestRunner.java:47)
	at com.intellij.rt.execution.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:242)
	at com.intellij.rt.execution.junit.JUnitStarter.main(JUnitStarter.java:70)
0
2019-04-12 20:30:00.171  INFO 10648 --- [       Thread-2] o.s.s.concurrent.ThreadPoolTaskExecutor  : Shutting down ExecutorService 'applicationTaskExecutor'
2019-04-12 20:30:00.177  INFO 10648 --- [       Thread-2] com.alibaba.druid.pool.DruidDataSource   : {dataSource-1} closed

Process finished with exit code 0

错误原因

• 分析

本次报错的原因在于sql语句未查询到数据，返回为null。而我们定义的dao层方法是返回为int，就会出现如下这样的提示：

return null from a method with a primitive return type (int).（试图从具有原始返回类型（int）的方法返回null）

Ingeter是int的包装类，int的初值为0，Ingeter的初值为null

• 解决方式

将dao层的返回类型改为Integer即可。