mapper：
@Select("SELECT COUNT(*) AS num FROM USER WHERE username=#{arg0} AND PASSWORD=#{arg1}")
public int isUserExists(String username,String password);
报错
org.apache.ibatis.binding.BindingException: Parameter 'arg0' not found. Available parameters are [username, param1, param2, password]
at org.apache.ibatis.binding.MapperMethod$ParamMap.get(MapperMethod.java:202) ~[mybatis-3.4.4.jar:3.4.4]
at org.apache.ibatis.reflection.wrapper.MapWrapper.get(MapWrapper.java:45) ~[mybatis-3.4.4.jar:3.4.4]
at org.apache.ibatis.reflection.MetaObject.getValue(MetaObject.java:122) ~[mybatis-3.4.4.jar:3.4.4]
at org.apache.ibatis.executor.BaseExecutor.createCacheKey(BaseExecutor.java:219) ~[mybatis-3.4.4.jar:3.4.4]
at org.apache.ibatis.executor.CachingExecutor.createCacheKey(CachingExecutor.java:146) ~[mybatis-3.4.4.jar:3.4.4]
at org.apache.ibatis.executor.CachingExecutor.query(CachingExecutor.java:82) ~[mybatis-3.4.4.jar:3.4.4]
at org.apache.ibatis.session.defaults.DefaultSqlSession.selectList(DefaultSqlSession.java:148) ~[mybatis-3.4.4.jar:3.4.4]
at org.apache.ibatis.session.defaults.DefaultSqlSession.selectList(DefaultSqlSession.java:141) ~[mybatis-3.4.4.jar:3.4.4]
at org.apache.ibatis.session.defaults.DefaultSqlSession.selectOne(DefaultSqlSession.java:77) ~[mybatis-3.4.4.jar:3.4.4]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.7.0_67]
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57) ~[na:1.7.0_67]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.7.0_67]
at java.lang.reflect.Method.invoke(Method.java:606) ~[na:1.7.0_67]
at org.mybatis.spring.SqlSessionTemplate$SqlSessionInterceptor.invoke(SqlSessionTemplate.java:433) ~[mybatis-spring-1.3.1.jar:1.3.1]
at com.sun.proxy.$Proxy53.selectOne(Unknown Source) ~[na:na]
at org.mybatis.spring.SqlSessionTemplate.selectOne(SqlSessionTemplate.java:166) ~[mybatis-spring-1.3.1.jar:1.3.1]
at org.apache.ibatis.binding.MapperMethod.execute(MapperMethod.java:82) ~[mybatis-3.4.4.jar:3.4.4]
at org.apache.ibatis.binding.MapperProxy.invoke(MapperProxy.java:59) ~[mybatis-3.4.4.jar:3.4.4]
at com.sun.proxy.$Proxy83.isUserExist(Unknown Source) ~[na:na]
at com.yjxc.service.impl.FrontServiceImpl.getUser(FrontServiceImpl.java:23) ~[classes/:na]
at com.yjxc.controller.front.FrontController.selectUser(FrontController.java:34) ~[classes/:na]
原因：JDK版本和mybatis jar包版本冲突
解决办法：改写
@Select("SELECT COUNT(*) AS num FROM USER WHERE username='username' AND PASSWORD='password'")
public int isUserExist(@Param("username")String username,@Param("password")String password);