记一次mybatis bindingexception 问题排查

看到的错误信息如出一辙都是这样的：Method threw 'org.apache.ibatis.binding.BindingException' exception.Invalid bound statement (not found): **.dao.**Dao.select

1.考虑返回值类型是否不匹配，一顿修改，@Results 也使用到。 最终无果。

2.开始各种百度，先申明本人使用的方式注解方式， 并非最常用的xml方式。 百度内容大都雷同，检查包名，类名，方法名 是否映射。无果。

3.由于 mybatis 报的错误，不是很明确。 无奈只能debug 源码。

4. 查看更为详细的异常日志

 org.apache.ibatis.binding.BindingException: Invalid bound statement (not found): com.sankuai.meituan.banma.thrift.activity.admin.dao.CouponPossessDao.selectUnusedPageNum
     at org.apache.ibatis.binding.MapperMethod$SqlCommand.<init>(MapperMethod.java:214) ~[mybatis-3.4.0.jar:3.4.0]
     at org.apache.ibatis.binding.MapperMethod.<init>(MapperMethod.java:48) ~[mybatis-3.4.0.jar:3.4.0]
     at org.apache.ibatis.binding.MapperProxy.cachedMapperMethod(MapperProxy.java:59) ~[mybatis-3.4.0.jar:3.4.0]
     at org.apache.ibatis.binding.MapperProxy.invoke(MapperProxy.java:52) ~[mybatis-3.4.0.jar:3.4.0]
     at com.sun.proxy.$Proxy96.selectUnusedPageNum(Unknown Source) ~[na:na]
     at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_131]
     at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_131]
     at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_131]
     at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_131]
     at com.dianping.zebra.dao.AsyncMapperProxy.invoke(AsyncMapperProxy.java:64) ~[zebra-dao-0.2.4.jar:na]
     at com.sun.proxy.$Proxy96.selectUnusedPageNum(Unknown Source) ~[na:na]

第二行是重点。点击查看代码。

  public SqlCommand(Configuration configuration, Class<?> mapperInterface, Method method) {
             String statementName = mapperInterface.getName() + "." + method.getName();
             MappedStatement ms = null;
             if(configuration.hasStatement(statementName)) { //正常的逻辑都会进入该 if 逻辑，然后得到ms。 该方法未进入该逻辑。不到是该方法初始化时，就失败了。
                 ms = configuration.getMappedStatement(statementName);
             } else if(!mapperInterface.equals(method.getDeclaringClass())) {
                 String parentStatementName = method.getDeclaringClass().getName() + "." + method.getName();
                 if(configuration.hasStatement(parentStatementName)) {
                     ms = configuration.getMappedStatement(parentStatementName);
                 }
             }

             if(ms == null) {
                 if(method.getAnnotation(Flush.class) == null) {
                     throw new BindingException("Invalid bound statement (not found): " + statementName); //该行即为抛出的异常日志
                 }

                 this.name = null;
                 this.type = SqlCommandType.FLUSH;
             } else {
                 this.name = ms.getId();
                 this.type = ms.getSqlCommandType();
                 if(this.type == SqlCommandType.UNKNOWN) {
                     throw new BindingException("Unknown execution method for: " + this.name);
                 }
             }

         }

下面开始追踪初始化的代码块。

 public class ZebraMapperFactoryBean<T> extends SqlSessionDaoSupport implements FactoryBean<T> {
     private Class<T> mapperInterface;
     private boolean addToConfig = true;

     public ZebraMapperFactoryBean() {
     }

     public void setMapperInterface(Class<T> mapperInterface) {
         this.mapperInterface = mapperInterface;
     }

     public void setAddToConfig(boolean addToConfig) {
         this.addToConfig = addToConfig;
     }

     protected void checkDaoConfig() {
         super.checkDaoConfig();
         Assert.notNull(this.mapperInterface, "Property 'mapperInterface' is required");
         Configuration configuration = this.getSqlSession().getConfiguration();
         if(this.addToConfig && !configuration.hasMapper(this.mapperInterface)) {
             try {
                 configuration.addMapper(this.mapperInterface);//下面跟进该方法查询具体的报错行
             } catch (Throwable var6) {
                 this.logger.error("Error while adding the mapper '" + this.mapperInterface + "' to configuration.", var6); // 初始化时，执行到这里其实已经报错了。但是没影响启动
                 throw new IllegalArgumentException(var6);
             } finally {
                 ErrorContext.instance().reset();
             }
         }

     }

public class MapperAnnotationBuilder {

    private SqlSource getSqlSourceFromAnnotations(Method method, Class<?> parameterType, LanguageDriver languageDriver) {
        try {
            Class<? extends Annotation> sqlAnnotationType = this.getSqlAnnotationType(method);
            Class<? extends Annotation> sqlProviderAnnotationType = this.getSqlProviderAnnotationType(method);
            Annotation sqlProviderAnnotation;
            if(sqlAnnotationType != null) {
                if(sqlProviderAnnotationType != null) {
                    throw new BindingException("You cannot supply both a static SQL and SqlProvider to method named " + method.getName());
                } else {
                    sqlProviderAnnotation = method.getAnnotation(sqlAnnotationType);
                    String[] strings = (String[])((String[])sqlProviderAnnotation.getClass().getMethod("value", new Class[0]).invoke(sqlProviderAnnotation, new Object[0]));
                    return this.buildSqlSourceFromStrings(strings, parameterType, languageDriver);
                }
            } else if(sqlProviderAnnotationType != null) {
                sqlProviderAnnotation = method.getAnnotation(sqlProviderAnnotationType);
                return new ProviderSqlSource(this.assistant.getConfiguration(), sqlProviderAnnotation);
            } else {
                return null;
            }
        } catch (Exception var8) {
            throw new BuilderException("Could not find value method on SQL annotation.  Cause: " + var8, var8); //最初的报错的位置
        }
    }

这里就可以找到具体的初始化失败的方法了。

5.至此找到了，正确的解决方案。

6.由此得出几个结论。1.mybatis 报警的确是很不明确。  2.出现问题，优先还是优先考虑排除法。一段代码一段代码检查。