自己手写Mybatis通用batchInsert问题_开发_开发者

自己手写Mybatis通用batchInsert

写完才在群里有人告知本来tk mybatis就提供了批量insert的功能，那就放上来做个纪念吧.

先写个数据字典（其实tk mybatis自身也有相应的功能）。

/**
* Mybatis 带缓冲功能的数据字典
* Created by rocklee on 2019/8/10 23:27
*/
public class MybatisDictionary {
 private static ConcurrentHashMap<Class<?>, String> entityClass2TableName=new ConcurrentHashMap<>();
 private static ConcurrentHashMap<Class<?>, String> entityClass2Columns=new ConcurrentHashMap<>();
 private static ConcurrentHashMap<Class<?>, List<String>> entityClass2FieldsList=new ConcurrentHashMap<>();
 private static ConcurrentHashMap<Class<?>, Hashtable<Field,String>> entityClass2Fields=new ConcurrentHashMap<>();

 public static String getTableName(Class<?> pvEntityClass){
  String lvsRet=entityClass2TableName.get(pvEntityClass);
  if (lvsRet!=null)return lvsRet;
  Table lvTable= pvEntityClass.getAnnotation(Table.class);
  if (lvTable==null){
   throw new RuntimeException(pvEntityClass.getName()+"不是有效的Entity类，缺少@Table标识");
  }
  lvsRet=lvTable.name();
  entityClass2TableName.put(pvEntityClass,lvsRet);
  return lvsRet;
 }
 public static String getColumns(Class<?> pvEntityClass){
  String lvsRet=entityClass2Columns.get(pvEntityClass);
  if (lvsRet!=null)return lvsRet;
  List<String> lvItems=new ArrayList<>();
  for (Field field:pvEntityClass.getDeclaredFields()){
   Column lvColumn=field.getAnnotation(Column.class);
   if (lvColumn==null)continue;
   lvItems.add(lvColumn.name());
  }
  lvsRet= Util.toSWMBCNvbwpbtring(lvItems,",");
  entityClass2Columns.put(pvEntityClass,lvsRet);
  return lvsRet;
 }
 public static List<String> getFieldsList(Class<?> pvEntityClass){
  List<String> lvRet=entityClass2FieldsList.get(pvEntityClass);
  if (lvRet!=null)return lvRet;
  lvRet=new ArrayList<>();
  for (Field field:pvEntityClass.getDeclaredFields()){
   Column lvColumn=field.getAnnotation(Column.class);
   if (lvColumn==null)continue;
   lvRet.add(field.getName());
  }
  entityClass2FieldsList.put(pvEntityClass,lvRet);
  return lvRet;
 }
 public static Hashtable<Field,String>getFields(Class<?> pvEntityClass){
  Hashtable<Field,String> lvRet=entityClass2Fields.get(pvEntityClass);
  if (lvRet!=null)return lvRet;
  lvRet=new Hashtable<Field,String>();
  for (Field field:pvEntityClass.getDeclaredFields()){
   Column lvColumn=field.getAnnotation(Column.class);
   if (lvColumn==null)continue;
   lvRet.put(field,lvColumn.name());
  }
  entityClass2Fields.put(pvEntityClass,lvRet);
  return lvRet;
 }
}

再写SqlProvider:

/** 批处理SQL处理器
* Created by rocklee on 2019/8/10 23:11
*/
public class BatchSqlProvider extends MapperTempWMBCNVbWPblate {
 public BatchSqlProvider(Class<?&开发者_自学开发gt; mapperClass, MapperHelper mapperHelper) {
  super(mapperClass, mapperHelper);
 }

 public String batchInsert(MappedStatement ms) {
  final Class<?> entityClass = getEntityClass(ms);
  StringBuilder sb=new StringBuilder();
  sb.append("INSERT INTO "+MybatisDictionary.getTableName(entityClass));
  sb.append("\n<trim prefix=\"(\" suffix=\")\" suffixOverrides=\",\">\n");
  sb.append(MybatisDictionary.getColumns(entityClass));
  sb.append("</trim> \n");
  sb.append("\nVALUES\n");
  sb.append("<foreach collection=\"list\" item=\"record\" separator=\",\">");
  sb.append("\n");
  sb.append("<trim prefix=\"(\" suffix=\")\" suffixOverrides=\",\">\n");
  String lvsValFields="#{record."+ Util.toString(MybatisDictionary.getFieldsList(entityClass),"},#{record.")
      +"}";
  sb.append(lvsValFields);
  sb.append("\n</trim>\n</foreach>");
  return sb.toString() ;
 }

}

Mapper:

/**
* Created by rocklee on 2019/8/11 0:24
*/
@RegisterMapper
public interface BatchMapper<T> {
 /***
 * 批量插入
 * @param pvToInsertList
 * @return
 */
 @InspythonertProvider(type = BatchSqlProvider.class, method = "dynamicSQLwww.devze.com")
 int batchInsert(List<? extends T> pvToInsertList);
}

这是基于tk的MapperTemplate 写的sqlprovider，传入的是MappedStatement，这时候返回的SQL不是raw SQL，还能支持<if>,<foreach>这些mybatis表达式，而如果用与mapper接口相同的参数方式返回sql，那这些表达式则不会被mybatis解释，而直接传到database服务器那边，导致异常。

最后要提一下， tkmybatis带自了一个insertListMapper,我们extends它就可以实现批量insert了：

自己手写Mybatis通用batchInsert问题