<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper
PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.upsoft.user.UserMapper">
    

<select id="queryByNameAndPass" parameterType="User" resultType="User">
    select * from account
    <where>
        <if test="user != null and user !=''">
            user = #{user}
        </if>
        <if test="pass != null and pass!=''">
            pass = #{pass}
        </if>
    </where>
</select>
</mapper>

package com.upsoft.test;

import java.io.IOException;
import java.io.InputStream;


import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;
import org.junit.Test;

import com.upsoft.user.User;
import com.upsoft.user.UserMapper;

public class TestMybatis {

    @Test
    public void test() throws IOException{
        
        InputStream in = Resources.getResourceAsStream("SqlMapConfig.xml");
        SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(in);
        SqlSession sqlSession = sqlSessionFactory.openSession();
        UserMapper userMapper = sqlSession.getMapper(UserMapper.class);
        User user = new User();
        user.setUser("feng");
        user.setPass("000");
        User user1 = userMapper.queryByNameAndPass(user);
        System.out.println(user1);
    }
}

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper
PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.upsoft.user.UserMapper">

    <select id="queryByNameAndPass" >
    select * from account
    <where>
        <if test="user != null and user !=''">
            user = #{user}
        </if>
        <if test="pass != null and pass!=''">
            pass = #{pass}
        </if>
    </where>
</select>
</mapper>

package com.upsoft.user;

import java.util.List;

public interface UserMapper {

    public User queryByNameAndPass(User user);
}

org.apache.ibatis.exceptions.PersistenceException: 
### Error querying database.  Cause: org.apache.ibatis.executor.ExecutorException: A query was run and no Result Maps were found for the Mapped Statement 'com.upsoft.user.UserMapper.queryByNameAndPass'.  It's likely that neither a Result Type nor a Result Map was specified.
### The error may exist in User.xml
### The error may involve defaultParameterMap
### The error occurred while setting parameters
### SQL: select * from account      WHERE user = ?                              and pass = ?
### Cause: org.apache.ibatis.executor.ExecutorException: A query was run and no Result Maps were found for the Mapped Statement 'com.upsoft.user.UserMapper.queryByNameAndPass'.  It's likely that neither a Result Type nor a Result Map was specified.
    at org.apache.ibatis.exceptions.ExceptionFactory.wrapException(ExceptionFactory.java:26)
    at org.apache.ibatis.session.defaults.DefaultSqlSession.selectList(DefaultSqlSession.java:111)
    at org.apache.ibatis.session.defaults.DefaultSqlSession.selectList(DefaultSqlSession.java:102)
    at org.apache.ibatis.session.defaults.DefaultSqlSession.selectOne(DefaultSqlSession.java:66)
    at org.apache.ibatis.binding.MapperMethod.execute(MapperMethod.java:68)
    at org.apache.ibatis.binding.MapperProxy.invoke(MapperProxy.java:52)
    at com.sun.proxy.$Proxy4.queryByNameAndPass(Unknown Source)
    at com.upsoft.test.TestMybatis.test(TestMybatis.java:28)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
    at java.lang.reflect.Method.invoke(Unknown Source)
    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.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)
    at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:78)
    at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:57)
    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.junit.runners.ParentRunner.run(ParentRunner.java:363)
    at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:86)
    at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:459)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:675)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:382)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:192)
Caused by: org.apache.ibatis.executor.ExecutorException: A query was run and no Result Maps were found for the Mapped Statement 'com.upsoft.user.UserMapper.queryByNameAndPass'.  It's likely that neither a Result Type nor a Result Map was specified.
    at org.apache.ibatis.executor.resultset.DefaultResultSetHandler.validateResultMapsCount(DefaultResultSetHandler.java:224)
    at org.apache.ibatis.executor.resultset.DefaultResultSetHandler.handleResultSets(DefaultResultSetHandler.java:147)
    at org.apache.ibatis.executor.statement.PreparedStatementHandler.query(PreparedStatementHandler.java:60)
    at org.apache.ibatis.executor.statement.RoutingStatementHandler.query(RoutingStatementHandler.java:73)
    at org.apache.ibatis.executor.SimpleExecutor.doQuery(SimpleExecutor.java:60)
    at org.apache.ibatis.executor.BaseExecutor.queryFromDatabase(BaseExecutor.java:267)
    at org.apache.ibatis.executor.BaseExecutor.query(BaseExecutor.java:137)
    at org.apache.ibatis.executor.CachingExecutor.query(CachingExecutor.java:96)
    at org.apache.ibatis.executor.CachingExecutor.query(CachingExecutor.java:77)
    at org.apache.ibatis.session.defaults.DefaultSqlSession.selectList(DefaultSqlSession.java:108)
    ... 29 more