花了几天的时间研究了一下mybatis的源代码，觉得这个框架还是很不错的。但是有一些缺陷的地方。
先来说说它和别的框架比起来我认为的好处：
（1）sql外置，把sql文件写在配置文件中加上强大的动态sql支持。
（2）利用cjk动态代理，实现配置文件映射接口。
这样我们在使用这套orm框架的时候就可以不再写那个拼接sql语句的dao实现类（dao-impl class），把dao实现类的工作都移交给那些*mapper.xml文件，如果数据库查询业务需要修改sql的话，那么只需要修改xml文件中的sql语句。
需要扩展的地方：
（1）没有内置物理分页的实现。
我们一般的习惯都是返回我们自己的分页实现类，网上大多的mybatis分页实现都是先返回分页列表，再查下返回总页数，然后处理成我们自己的分页类。我自己也写了一个分页，把这部分工作交给mybatis来处理，以后会把代码贴出来。
（2）公用范型接口dao
公用范型接口dao类几乎成为我们开发中最长使用的，把一些长操作的方法封装一下，供我们的业务dao调用，但是在mybatis中，我现在不想再写dao的实现类，只有接口类，取缔他的是mapper-xml文件，这样如何才能封装我们的公用方法呢。
幸好mybatis提供了插件拦截器，我们可以在不修改mybatis源码的基础上来扩展它的功能。
好忙啊，花了些时间写了一个范型接口dao，还没有经过验证，先贴上代码。
使用方法很简单，只要你使用MappInterceptor这个拦截器，在你的Mapper接口中继承这个IGenericDao这样 公用的方法就可以使用了，这样的好处是在一般业务的类中不用再写Dao的实现，直接使用 IGenericDao中提供的方法就ok
公用dao，你的接口只要继承这个dao就可以使用里面的方法。
package org.cf.guott.mybatis;import java.util.List;import org.apache.ibatis.annotations.Delete;import org.apache.ibatis.annotations.Insert;import org.apache.ibatis.annotations.Select;import org.apache.ibatis.annotations.Update;import org.cf.guott.mybatis.pagination.PageMyBatis;public interface IGenericDao<T,PK> { @Select("MapperGD.find.entityById") public T findEntityById(PK id); @Select("MapperGD.find.entitys") public List<T> findEntity(Object... obj); @Select("MapperGD.find.ListByLike") public List<T> findLikeEntity(Object... obj); @Insert("MapperGD.insert.entity") public void insertEntity(T t); @Update("MapperGD.update.entity") public void updateEntityById(T entity); @Delete("MapperGD.delete.id") public void deleteById(PK id); @Delete("MapperGD.delete.condition") public void deleteByCondition(Object param); @Select("MapperGD.find.entity.queryByVo") public PageMyBatis<T> queryByVo(int i,int c,Object... obj); @Select("MapperGD.find.entity.queryByVoLike") public PageMyBatis<T> LikequeryByVo(int i,int c,Object... obj); }
这个一个拦截器，来处理你的公用dao中的方法
package org.cf.guott.mybatis.dbmapper.interceptor;import java.util.Map;import java.util.Properties;import org.apache.commons.lang3.reflect.FieldUtils;import org.apache.ibatis.executor.Executor;import org.apache.ibatis.mapping.BoundSql;import org.apache.ibatis.mapping.MappedStatement;import org.apache.ibatis.plugin.Interceptor;import org.apache.ibatis.plugin.Intercepts;import org.apache.ibatis.plugin.Invocation;import org.apache.ibatis.plugin.Plugin;import org.apache.ibatis.plugin.Signature;import org.apache.ibatis.session.ResultHandler;import org.apache.ibatis.session.RowBounds;import org.cf.guott.mybatis.helpers.MapperSqlHelper;import org.cf.guott.mybatis.pagination.MappedStatmentHelper; @Intercepts({ @Signature( type = Executor.class, method = "query", args = {MappedStatement.class, Object.class, RowBounds.class, ResultHandler.class}) ,@Signature( type = Executor.class, method = "update", args = {MappedStatement.class, Object.class}) }) public class MappInterceptor implements Interceptor{ private final static String _sql_regex = ".*MapperGD.*"; @SuppressWarnings("unchecked") private void processIntercept(final Object[] queryArgs) { final MappedStatement ms = (MappedStatement) queryArgs[0]; final Object parameter = queryArgs[1]; String mapperSQL = ms.getBoundSql(parameter).getSql(); BoundSql boundSQL = ms.getBoundSql(parameter); Class<?> entityclazz = MappedStatmentHelper.getEntityClazz(ms.getResource()); queryArgs[0] = MappedStatmentHelper.setMSReturnSetMap(ms, entityclazz); boolean interceptor = mapperSQL.matches(_sql_regex); if(!interceptor){ return; } if(entityclazz == null){ throw new RuntimeException("使用公共dao必須給mapper接口的@MyBatisRepository(User.class) 注解設置值."); } String new_sql = MapperSqlHelper.getExecuSQL(entityclazz,mapperSQL,parameter); BoundSql newBoundSql = MappedStatmentHelper.copyFromBoundSql(ms, boundSQL, new_sql); MappedStatement newMs = MappedStatmentHelper .copyFromMappedStatement(ms, newBoundSql); queryArgs[0] = newMs; } public Object intercept(Invocation invocation) throws Throwable { processIntercept(invocation.getArgs()); return invocation.proceed(); } public Object plugin(Object o) { return Plugin.wrap(o, this); } public void setProperties(Properties arg0) { } } 这个类来处理你的sql语句 package org.cf.guott.mybatis.helpers;import java.lang.annotation.Annotation;import java.lang.reflect.Field;import java.util.Arrays;import java.util.Collection;import java.util.Map;import org.apache.commons.lang3.reflect.FieldUtils;import org.cf.guott.mybatis.annotation.MyBatisColumn;import org.cf.guott.mybatis.annotation.MyBatisRepository;import org.cf.guott.mybatis.annotation.MybatisID;import org.cf.guott.mybatis.annotation.MybatisTable;import org.cf.guott.mybatis.entity.User;public class MapperSqlHelper{ public static final Class<? extends Annotation> MYBATISREPOSITORY = MyBatisRepository.class; public static final Class<? extends Annotation> MYBATISTABLE = MybatisTable.class; public static final Class<? extends Annotation> MYBATISCOLUMN = MyBatisColumn.class; public static final Class<? extends Annotation> MYBATISID = MybatisID.class; public String getUpdateSQL(){ return null; } /** * 传入mapper接口class * @param mapperclazz * @return */ private String insertEntity(Class<?> clazz){ StringBuilder sql = new StringBuilder(); StringBuilder intosql = new StringBuilder(); StringBuilder valuessql = new StringBuilder(); if(!clazz.isAnnotationPresent(MYBATISTABLE)){ sql.append("INSERT INTO "+clazz.getName()); }else{ MybatisTable antable = (MybatisTable)clazz.getAnnotation(MYBATISTABLE); if(antable.value() == ""){ sql.append("INSERT INTO "+clazz.getName()); }else{ sql.append("INSERT INTO "+antable.value()); } } Field[] files = clazz.getDeclaredFields(); intosql.append("("); for(Field file : files){ file.setAccessible(true); if(file.isAnnotationPresent(MYBATISCOLUMN)){ MyBatisColumn anColumn = (MyBatisColumn)file.getAnnotation(MYBATISCOLUMN); if(!anColumn.isAutoKey()){ if(anColumn.value().equals("")){ intosql.append(file.getName()+","); }else{ intosql.append(anColumn.value()+","); } } }else{ intosql.append(file.getName()+","); } } valuessql.append(" values ("); for(Field file : files){ file.setAccessible(true); if(file.isAnnotationPresent(MYBATISCOLUMN)){ MyBatisColumn anColumn = (MyBatisColumn)file.getAnnotation(MYBATISCOLUMN); if(!anColumn.isAutoKey()){ if(anColumn.value().equals("")){ valuessql.append("#{"+file.getName()+"},"); }else{ valuessql.append("#{"+file.getName()+"},"); } } }else{ valuessql.append("#{"+file.getName()+"},"); } } return sql.append(intosql.substring(0, intosql.length()-1)).append(") ").append(valuessql.substring(0, valuessql.length()-1)).append(")").toString(); } /** * 传入mapper接口class * @param mapperclazz * @return */ private String updateEntityById(Class<?> clazz){ StringBuilder sql = new StringBuilder(); StringBuilder set = new StringBuilder(); StringBuilder wheresql = new StringBuilder(); if(!clazz.isAnnotationPresent(MYBATISTABLE)){ sql.append("UPDATE "+clazz.getName()); }else{ MybatisTable antable = (MybatisTable)clazz.getAnnotation(MYBATISTABLE); if(antable.value() == ""){ sql.append("UPDATE "+clazz.getName()); }else{ sql.append("UPDATE "+antable.value()); } } Field[] files = clazz.getDeclaredFields(); set.append(" set "); wheresql.append(" where 1=1 "); for(Field file : files){ file.setAccessible(true); if(file.isAnnotationPresent(MYBATISCOLUMN)){ MyBatisColumn anColumn = (MyBatisColumn)file.getAnnotation(MYBATISCOLUMN); if(!anColumn.isID()){//判断字段不为主键 if(anColumn.value().equals("")){ set.append(file.getName()+" = #{"+file.getName()+"} ,"); }else{ set.append(anColumn.value()+" = #{"+file.getName()+"} ,"); } }else{ if(anColumn.value().equals("")){ wheresql.append(" and "+file.getName()+" = #{"+file.getName()+"},"); }else{ wheresql.append(" and "+anColumn.value()+" = #{"+anColumn.value()+"},"); } } }else{ set.append(file.getName()+" = #{"+file.getName()+"} ,"); } } if(wheresql.equals(" where 1=1 ")){ throw new RuntimeException("实体变量没有设置ID字段值"); } sql.append(set.substring(0, set.length()-1)).append(wheresql.substring(0, wheresql.length()-1)); return sql.toString(); } private String findEntityAll(Class<?> clazz,Object args,boolean islike){ StringBuilder sql = new StringBuilder(); StringBuilder whereSQL = new StringBuilder(" where 1=1 "); StringBuffer orderby = new StringBuffer(); if(!clazz.isAnnotationPresent(MYBATISTABLE)){ sql.append("select * from "+clazz.getName()); }else{ MybatisTable antable = (MybatisTable)clazz.getAnnotation(MYBATISTABLE); if(antable.value() == ""){ sql.append("select * from "+clazz.getSimpleName()); }else{ sql.append("select * from "+antable.value()); } } Object[] paramObjs = (Object[]) ((Map)args).get("array"); if(paramObjs != null && paramObjs.length>0){ Object param = paramObjs[0]; if(param != null ){ if(param instanceof Map){ Map<String,Object> map = (Map)param; if(map.containsKey("orderby")){ orderby.append(" order by "+map.get("orderby")); } if(map.containsKey("sortby")){ orderby.append(" "+map.get("sortby")+" "); } for(String key : map.keySet()) { if(islike) whereSQL.append(" and "+key + " like '%" + map.get(key)+"%',"); else whereSQL.append(" and "+key + " = '" + map.get(key)+"',"); } sql.append(whereSQL.subSequence(0,whereSQL.length()-1)).append(orderby); }else if(param instanceof Conditions){ Conditions<String,Object> map = (Conditions)param; if(map.containsKey("orderby")){ orderby.append(" order by "+map.get("orderby")); } if(map.containsKey("sortby")){ orderby.append(" "+map.get("sortby")+" "); } for(String key : map.keySet()) { if(key.equals("orderby") || key.equals("sortby")){ continue; } if(islike) whereSQL.append(" and "+key + " like '%" + map.get(key)+"%',"); else whereSQL.append(" and "+key + " = '" + map.get(key)+"',"); } sql.append(whereSQL.subSequence(0,whereSQL.length()-1)).append(orderby); } } } return sql.toString(); } private String findEntityById(Class<?> clazz){ StringBuilder sql = new StringBuilder(); if(!clazz.isAnnotationPresent(MYBATISTABLE)){ sql.append("select * from "+clazz.getName()); }else{ MybatisTable antable = (MybatisTable)clazz.getAnnotation(MYBATISTABLE); if(antable.value() == ""){ sql.append("select * from "+clazz.getSimpleName()); }else{ sql.append("select * from "+antable.value()); } } sql.append(" where 1=1 "); Field[] files = clazz.getDeclaredFields(); boolean falg = false; for(Field file : files){ file.setAccessible(true); if(file.isAnnotationPresent(MyBatisColumn.class)){ MyBatisColumn anColumn = (MyBatisColumn)file.getAnnotation(MYBATISCOLUMN); if(anColumn.isID()){//判断字段不为主键 falg = true; if(anColumn.value().equals("")){ sql.append(" and "+file.getName()+" = #{"+file.getName()+"},"); }else{ sql.append(" and "+file.getName()+" = #{"+file.getName()+"},"); } } } } if(!falg){ throw new RuntimeException("不能通過id查詢實體,實體中沒有定義@mybatisID"); } return sql.subSequence(0, sql.length()-1).toString(); } public String deleteById(Class<?> clazz){ StringBuilder sql = new StringBuilder(); StringBuilder wheresql = new StringBuilder(" where 1=1 "); if(!clazz.isAnnotationPresent(MYBATISTABLE)){ sql.append("delete "+clazz.getName()); }else{ MybatisTable antable = (MybatisTable)clazz.getAnnotation(MYBATISTABLE); if(antable.value() == ""){ sql.append("delete "+clazz.getName()); }else{ sql.append("delete "+antable.value()); } } Field[] files = clazz.getDeclaredFields(); for(Field file : files){ file.setAccessible(true); if(file.isAnnotationPresent(MYBATISCOLUMN)){ MyBatisColumn anColumn = (MyBatisColumn)file.getAnnotation(MYBATISCOLUMN); if(anColumn.isID()){//判断字段不为主键 if(anColumn.value().equals("")){ wheresql.append(" and "+file.getName()+" = #{"+file.getName()+"},"); }else{ wheresql.append(" and "+anColumn.value()+" = #{"+anColumn.value()+"},"); } } } } if(wheresql.equals(" where 1=1 ")){ throw new RuntimeException("实体变量没有设置ID字段值"); } sql.append(wheresql.substring(0,wheresql.length()-1)); return sql.toString(); } public String queryByVo(Class<?> clazz,Object args,boolean islike){ StringBuilder sql = new StringBuilder(); StringBuilder whereSQL = new StringBuilder(" where 1=1 "); StringBuilder orderbySQL = new StringBuilder(""); if(!clazz.isAnnotationPresent(MYBATISTABLE)){ sql.append("select * from "+clazz.getName()); }else{ MybatisTable antable = (MybatisTable)clazz.getAnnotation(MYBATISTABLE); if(antable.value() == ""){ sql.append("select * from "+clazz.getName()); }else{ sql.append("select * from "+antable.value()); } } if(args instanceof Map){ Map map = (Map)args; Object[] arr = (Object[])map.get("param3"); if(arr.length>0){ Map<String,Object> params = (Map)arr[0]; if(params.containsKey("orderby")){ orderbySQL.append(" order by "+params.get("orderby")); } if(params.containsKey("sortby")){ orderbySQL.append(" "+params.get("sortby")+" "); } for(String key:params.keySet()){ if(key.equals("orderby") || key.equals("sortby")){ continue; } if(islike) whereSQL.append(" and "+key + " like '%" + params.get(key)+"%',"); else whereSQL.append(" and "+key + " = '" + params.get(key)+"',"); } } } return sql.append(whereSQL.substring(0, whereSQL.length()-1)).append(orderbySQL).toString(); } public String count(Class<?> clazz,Object args){ StringBuilder sql = new StringBuilder(); StringBuilder whereSQL = new StringBuilder(" where 1=1 "); if(!clazz.isAnnotationPresent(MYBATISTABLE)){ sql.append("select count(*) from "+clazz.getName()); }else{ MybatisTable antable = (MybatisTable)clazz.getAnnotation(MYBATISTABLE); if(antable.value() == ""){ sql.append("select count(*) from "+clazz.getName()); }else{ sql.append("select count(*) from "+antable.value()); } } Object[] paramObjs = (Object[]) ((Map)args).get("array"); if(paramObjs != null && paramObjs.length>0){ Object param = paramObjs[0]; if(param != null ){ if(param instanceof Map){ Map<String,Object> map = (Map)param; for(String key : map.keySet()) { whereSQL.append(" and "+key + " = '" + map.get(key)+"',"); } sql.append(whereSQL.subSequence(0,whereSQL.length()-1)); }else if(param instanceof Conditions){ Conditions<String,Object> map = (Conditions)param; for(String key : map.keySet()) { whereSQL.append(" and "+key + " = '" + map.get(key)+"',"); } sql.append(whereSQL.subSequence(0,whereSQL.length()-1)); } } } return sql.toString(); } public String deleteByCondition(Class<?> clazz,Object param){ StringBuilder sql = new StringBuilder(); StringBuilder whereSQL = new StringBuilder(" where 1=1 "); if(!clazz.isAnnotationPresent(MYBATISTABLE)){ sql.append("delete "+clazz.getName()); }else{ MybatisTable antable = (MybatisTable)clazz.getAnnotation(MYBATISTABLE); if(antable.value() == ""){ sql.append("delete "+clazz.getName()); }else{ sql.append("delete "+antable.value()); } } if(param != null ){ if(param instanceof Map){ Map<String,Object> map = (Map)param; for(String key : map.keySet()) { whereSQL.append(" and "+key + " = '" + map.get(key)+"',"); } sql.append(whereSQL.subSequence(0,whereSQL.length()-1)); }else if(param instanceof Conditions){ Conditions<String,Object> map = (Conditions)param; for(String key : map.keySet()) { whereSQL.append(" and "+key + " = '" + map.get(key)+"',"); } sql.append(whereSQL.subSequence(0,whereSQL.length()-1)); } } if(whereSQL.equals(" where 1=1 ")){ throw new RuntimeException("实体变量没有设置ID字段值"); } return sql.toString(); } private static MapperSqlHelper App(){ return new MapperSqlHelper(); } public static String getExecuSQL(Class<?> clazz, String mapperDBsql,Object param) { if(mapperDBsql.equals("MapperGD.find.entitys")){ return MapperSqlHelper.App().findEntityAll(clazz,param,false);//条件查询实体列表 }else if(mapperDBsql.equals("MapperGD.find.entityById")){ return MapperSqlHelper.App().findEntityById(clazz);//id查询实体 }else if(mapperDBsql.equals("MapperGD.find.ListByLike")){ return MapperSqlHelper.App().findEntityAll(clazz,param,true);//条件查询实体列表 }else if(mapperDBsql.equals("MapperGD.insert.entity")){ return MapperSqlHelper.App().insertEntity(clazz);//保存单一实体 }else if(mapperDBsql.equals("MapperGD.update.entity")){ return MapperSqlHelper.App().updateEntityById(clazz);//保存单一实体 }else if(mapperDBsql.equals("MapperGD.update.entity.condistion")){ return mapperDBsql; }else if(mapperDBsql.equals("MapperGD.delete.id")){ return MapperSqlHelper.App().deleteById(clazz); }else if(mapperDBsql.equals("MapperGD.delete.condition")){ return MapperSqlHelper.App().deleteByCondition(clazz,param); }else if(mapperDBsql.equals("MapperGD.count.condition")){ return MapperSqlHelper.App().count(clazz,param); }else if(mapperDBsql.equals("MapperGD.find.entity.queryByVo")){ return MapperSqlHelper.App().queryByVo(clazz,param,false); }else if(mapperDBsql.equals("MapperGD.find.entity.queryByVoLike")){ return MapperSqlHelper.App().queryByVo(clazz,param,true); } return null; } //预留接口 private String updateEntityByConditions(Class<?> clazz,Object param){ return null; } public void getParam(Object param){ StringBuffer bf = new StringBuffer(); if (isPrimitiveType(param.getClass())) { bf.append(param); } else if (param instanceof Map) { Map<String,Object> map = (Map)param; } } public static boolean isPrimitiveType(Class clazz) { return clazz != null && (clazz.isPrimitive() || clazz.equals(Long.class) || clazz.equals(Integer.class) || clazz.equals(Short.class) || clazz.equals(Byte.class) || clazz.equals(Double.class) || clazz.equals(Float.class) || clazz.equals(Boolean.class) || clazz.equals(Character.class) || clazz.equals(String.class)); } public static void main(String[] args) {// Object object = null;// if (isPrimitiveType(object.getClass())) {// } else if (object instanceof Map) {// } Field[] files = User.class.getDeclaredFields(); User u = new User(); try { System.out.println(FieldUtils.readDeclaredField(u, "id",true)); } catch (IllegalAccessException e) { // TODO Auto-generated catch block e.printStackTrace(); } }} 测试用例：
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