“产品名”相同的数据记录有多条，java用getByProName()查询报错

Question

BUG: 数据库中产品名相同的记录有多条，当调用getByProName() 时会得到不止一条该“产品名”的数据记录,会报错

单元测试方法：
@Test
public void testQueryByProName() {
String proName = "小王子饼干";
Products products = productsDao.queryByProName(proName);
System.out.println("产品名： " + products.getProName());
System.out.println("信息： " + products);
// log.info("products ={} ", products);
}

报错：
org.mybatis.spring.MyBatisSystemException: nested exception is org.apache.ibatis.exceptions.TooManyResultsException: Expected one result (or null) to be returned by selectOne(), but found: 6
at org.mybatis.spring.MyBatisExceptionTranslator.translateExceptionIfPossible(MyBatisExceptionTranslator.java:75)
at org.mybatis.spring.SqlSessionTemplate$SqlSessionInterceptor.invoke(SqlSessionTemplate.java:371)
at com.sun.proxy.$Proxy13.selectOne(Unknown Source)
at org.mybatis.spring.SqlSessionTemplate.selectOne(SqlSessionTemplate.java:163)
at org.apache.ibatis.binding.MapperMethod.execute(MapperMethod.java:68)
at org.apache.ibatis.binding.MapperProxy.invoke(MapperProxy.java:52)
at com.sun.proxy.$Proxy14.queryByProName(Unknown Source)
at cn.syy.test.dao.ProductsDaoTest.testQueryByProName(ProductsDaoTest.java:43)

Caused by: org.apache.ibatis.exceptions.TooManyResultsException: Expected one result (or null) to be returned by selectOne(), but found: 6
at org.apache.ibatis.session.defaults.DefaultSqlSession.selectOne(DefaultSqlSession.java:70)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:606)
at org.mybatis.spring.SqlSessionTemplate$SqlSessionInterceptor.invoke(SqlSessionTemplate.java:358)
... 35 more

------- 然后我的解决思路：把返回的多条proname相同的数据记录放到List里，遍历输出，单元测试依然报错（相同的错）

修改单元测试方法：
@Test
public void testQueryByProName() {
String proName = "小王子饼干";
List list = (List) productsDao.queryByProName(proName);
for(Products p : list){
System.out.println("产品名： " + p.getProName());
System.out.println("信息： " + p);
}
}

org.mybatis.spring.MyBatisSystemException: nested exception is org.apache.ibatis.exceptions.TooManyResultsException: Expected one result (or null) to be returned by selectOne(), but found: 6
at org.mybatis.spring.MyBatisExceptionTranslator.translateExceptionIfPossible(MyBatisExceptionTranslator.java:75)
at org.mybatis.spring.SqlSessionTemplate$SqlSessionInterceptor.invoke(SqlSessionTemplate.java:371)
at com.sun.proxy.$Proxy13.selectOne(Unknown Source)
at org.mybatis.spring.SqlSessionTemplate.selectOne(SqlSessionTemplate.java:163)
at org.apache.ibatis.binding.MapperMethod.execute(MapperMethod.java:68)
at org.apache.ibatis.binding.MapperProxy.invoke(MapperProxy.java:52)
at com.sun.proxy.$Proxy14.queryByProName(Unknown Source)
at cn.syy.test.dao.ProductsDaoTest.testQueryByProName(ProductsDaoTest.java:52)

Caused by: org.apache.ibatis.exceptions.TooManyResultsException: Expected one result (or null) to be returned by selectOne(), but found: 6
at org.apache.ibatis.session.defaults.DefaultSqlSession.selectOne(DefaultSqlSession.java:70)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:606)
at org.mybatis.spring.SqlSessionTemplate$SqlSessionInterceptor.invoke(SqlSessionTemplate.java:358)
... 35 more

请问有啥办法能把proname相同的数据记录查询出来么？

Answer 1

List<Products > list = productsDao.queryByProName(proName);

productsDao里的queryByProName方法改为返回List。
同样，访问数据的持久层用的什么技术(mybatis？），queryByProName调用的sql也需要返回多条结果。

修改的不只是一处。