feat：添加 selectOneByQueryAs 等方法，方便在 left join 等场景直接转换为 dto vo 等; close #I72XOK

mybatis-flex-core/src/main/java/com/mybatisflex/core/BaseMapper.java

@@ -323,6 +323,19 @@ public interface BaseMapper<T> {
         return (entities == null || entities.isEmpty()) ? null : entities.get(0);
     }
 
+
+    /**
+     * 根据 queryWrapper 构建的条件来查询 1 条数据
+     *
+     * @param queryWrapper query 条件
+     * @param asType       接收类型
+     * @return 数据内容
+     */
+    default <R> R selectOneByQueryAs(QueryWrapper queryWrapper, Class<R> asType) {
+        List<R> entities = selectListByQueryAs(queryWrapper.limit(1), asType);
+        return (entities == null || entities.isEmpty()) ? null : entities.get(0);
+    }
+
     /**
      * 根据多个主键来查询多条数据
      *
@@ -390,6 +403,17 @@ public interface BaseMapper<T> {
     List<T> selectListByQuery(@Param(FlexConsts.QUERY) QueryWrapper queryWrapper);
 
 
+    /**
+     * 根据 query 来构建条件查询数据列表，要求返回的数据为 asType
+     * 这种场景一般用在 left join 时，有多出了 entity 本身的字段内容，可以转换为 dto、vo 等场景时
+     *
+     * @param queryWrapper 查询条件
+     * @param asType       接收数据类型
+     * @return 数据列表
+     */
+    @SelectProvider(type = EntitySqlProvider.class, method = "selectListByQuery")
+    <R> List<R> selectListByQueryAs(@Param(FlexConsts.QUERY) QueryWrapper queryWrapper, Class<R> asType);
+
     /**
      * 查询全部数据
      *
@@ -545,10 +569,44 @@ public interface BaseMapper<T> {
      * @return page 数据
      */
     default Page<T> paginate(Page<T> page, QueryWrapper queryWrapper) {
-
         List<QueryColumn> groupByColumns = CPI.getGroupByColumns(queryWrapper);
         List<QueryColumn> selectColumns = CPI.getSelectColumns(queryWrapper);
 
+        // 只有 totalRow 小于 0 的时候才会去查询总量
+        // 这样方便用户做总数缓存，而非每次都要去查询总量
+        // 一般的分页场景中，只有第一页的时候有必要去查询总量，第二页以后是不需要的
+        if (page.getTotalRow() < 0) {
+
+            //清除group by 去查询数据
+            CPI.setGroupByColumns(queryWrapper, null);
+            CPI.setSelectColumns(queryWrapper, Arrays.asList(count()));
+
+            long count = selectCountByQuery(queryWrapper);
+            page.setTotalRow(count);
+        }
+
+        if (page.getTotalRow() == 0 || page.getPageNumber() > page.getTotalPage()) {
+            return page;
+        }
+
+
+        //恢复数量查询清除的 groupBy
+        CPI.setGroupByColumns(queryWrapper, groupByColumns);
+
+        //重置 selectColumns
+        CPI.setSelectColumns(queryWrapper, selectColumns);
+
+        int offset = page.getPageSize() * (page.getPageNumber() - 1);
+        queryWrapper.limit(offset, page.getPageSize());
+        List<T> rows = selectListByQuery(queryWrapper);
+        page.setRecords(rows);
+        return page;
+    }
+
+
+    default <R> Page<R> paginateAs(Page<R> page, QueryWrapper queryWrapper, Class<R> asType) {
+        List<QueryColumn> groupByColumns = CPI.getGroupByColumns(queryWrapper);
+        List<QueryColumn> selectColumns = CPI.getSelectColumns(queryWrapper);
 
         // 只有 totalRow 小于 0 的时候才会去查询总量
         // 这样方便用户做总数缓存，而非每次都要去查询总量
@@ -575,8 +633,8 @@ public interface BaseMapper<T> {
 
         int offset = page.getPageSize() * (page.getPageNumber() - 1);
         queryWrapper.limit(offset, page.getPageSize());
-        List<T> rows = selectListByQuery(queryWrapper);
+        List<R> records = selectListByQueryAs(queryWrapper, asType);
-        page.setRecords(rows);
+        page.setRecords(records);
         return page;
     }
 }

mybatis-flex-core/src/main/java/com/mybatisflex/core/FlexConsts.java

@@ -39,6 +39,7 @@ public class FlexConsts {
     public static final String IGNORE_NULLS = "$$ignoreNulls";
 
     public static final String METHOD_INSERT_BATCH = "insertBatch";
+    public static final String METHOD_SELECT_LIST_BY_QUERY_AS = "selectListByQueryAs";
 
     /**
      * 当 entity 使用逻辑删除时，0 为 entity 的正常状态

mybatis-flex-core/src/main/java/com/mybatisflex/core/mybatis/FlexConfiguration.java

@@ -126,6 +126,20 @@ public class FlexConfiguration extends Configuration {
     }
 
 
+    @Override
+    public MappedStatement getMappedStatement(String id) {
+        MappedStatement ms = super.getMappedStatement(id);
+
+        //动态 resultsMap
+        if (id.endsWith(FlexConsts.METHOD_SELECT_LIST_BY_QUERY_AS)) {
+            Class<?> asType = MappedStatementTypes.getCurrentType();
+            ms = replaceResultMap(ms, TableInfoFactory.ofEntityClass(asType));
+        }
+
+        return ms;
+    }
+
+
     @Override
     public void addMappedStatement(MappedStatement ms) {
         //替换 RowMapper.insert 的主键生成器
@@ -141,7 +155,7 @@ public class FlexConfiguration extends Configuration {
         //entity select
         else if (StringUtil.endsWithAny(ms.getId(), "selectOneById", "selectListByIds"
                 , "selectListByQuery")) {
-            ms = replaceResultMap(ms);
+            ms = replaceResultMap(ms, getTableInfo(ms));
         }
 
         super.addMappedStatement(ms);
@@ -151,9 +165,8 @@ public class FlexConfiguration extends Configuration {
     /**
      * 替换 entity 查询的 ResultMap
      */
-    private MappedStatement replaceResultMap(MappedStatement ms) {
+    private MappedStatement replaceResultMap(MappedStatement ms, TableInfo tableInfo) {
 
-        TableInfo tableInfo = getTableInfo(ms);
         if (tableInfo == null) {
             return ms;
         }

mybatis-flex-core/src/main/java/com/mybatisflex/core/mybatis/MappedStatementTypes.java

@@ -0,0 +1,34 @@
+/**
+ * Copyright (c) 2022-2023, Mybatis-Flex (fuhai999@gmail.com).
+ * <p>
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ * <p>
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * <p>
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.mybatisflex.core.mybatis;
+
+public class MappedStatementTypes {
+
+    private static ThreadLocal<Class<?>> currentTypeTL = new ThreadLocal<>();
+
+    static void setCurrentType(Class<?> type){
+        currentTypeTL.set(type);
+    }
+
+    static Class<?> getCurrentType(){
+        return currentTypeTL.get();
+    }
+
+    static void clear(){
+        currentTypeTL.remove();
+    }
+
+}

mybatis-flex-core/src/main/java/com/mybatisflex/core/mybatis/MapperInvocationHandler.java

@@ -16,6 +16,7 @@
 package com.mybatisflex.core.mybatis;
 
 import com.mybatisflex.annotation.UseDataSource;
+import com.mybatisflex.core.FlexConsts;
 import com.mybatisflex.core.FlexGlobalConfig;
 import com.mybatisflex.core.datasource.DataSourceKey;
 import com.mybatisflex.core.datasource.FlexDataSource;
@@ -45,7 +46,11 @@ public class MapperInvocationHandler implements InvocationHandler {
     public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
         boolean clearDsKey = false;
         boolean clearDbType = false;
+        boolean isSelectListByQueryAsMethod = FlexConsts.METHOD_SELECT_LIST_BY_QUERY_AS.equals(method.getName());
         try {
+            if (isSelectListByQueryAsMethod){
+                MappedStatementTypes.setCurrentType((Class<?>) args[1]);
+            }
             //获取用户动态指定，由用户指定数据源，则应该有用户清除
             String dataSourceKey = DataSourceKey.get();
 
@@ -73,6 +78,9 @@ public class MapperInvocationHandler implements InvocationHandler {
             }
             return method.invoke(mapper, args);
         } finally {
+            if (isSelectListByQueryAsMethod){
+                MappedStatementTypes.clear();
+            }
             if (clearDbType) {
                 DialectFactory.clearHintDbType();
             }

mybatis-flex-core/src/main/java/com/mybatisflex/core/table/TableInfoFactory.java

@@ -117,7 +117,6 @@ public class TableInfoFactory {
         tableInfo.setEntityClass(entityClass);
         tableInfo.setReflector(new Reflector(entityClass));
 
-
         //初始化表名
         Table table = entityClass.getAnnotation(Table.class);
         if (table != null) {

mybatis-flex-test/mybatis-flex-native-test/src/main/java/com/mybatisflex/test/ArticleDTO.java

@@ -0,0 +1,90 @@
+package com.mybatisflex.test;
+
+import java.util.Date;
+
+public class ArticleDTO {
+
+    private Long id;
+
+    private Long accountId;
+
+    private String title;
+
+    private String content;
+
+
+    private String userName;
+
+    private int age;
+
+    private Date birthday;
+
+    public Long getId() {
+        return id;
+    }
+
+    public void setId(Long id) {
+        this.id = id;
+    }
+
+    public Long getAccountId() {
+        return accountId;
+    }
+
+    public void setAccountId(Long accountId) {
+        this.accountId = accountId;
+    }
+
+    public String getTitle() {
+        return title;
+    }
+
+    public void setTitle(String title) {
+        this.title = title;
+    }
+
+    public String getContent() {
+        return content;
+    }
+
+    public void setContent(String content) {
+        this.content = content;
+    }
+
+    public String getUserName() {
+        return userName;
+    }
+
+    public void setUserName(String userName) {
+        this.userName = userName;
+    }
+
+    public int getAge() {
+        return age;
+    }
+
+    public void setAge(int age) {
+        this.age = age;
+    }
+
+    public Date getBirthday() {
+        return birthday;
+    }
+
+    public void setBirthday(Date birthday) {
+        this.birthday = birthday;
+    }
+
+    @Override
+    public String toString() {
+        return "ArticleDTO{" +
+                "id=" + id +
+                ", accountId=" + accountId +
+                ", title='" + title + '\'' +
+                ", content='" + content + '\'' +
+                ", userName='" + userName + '\'' +
+                ", age=" + age +
+                ", birthday=" + birthday +
+                '}';
+    }
+}

mybatis-flex-test/mybatis-flex-native-test/src/main/java/com/mybatisflex/test/EntityTestStarter.java

@@ -28,6 +28,7 @@ import javax.sql.DataSource;
 import java.util.List;
 
 import static com.mybatisflex.test.table.Tables.ACCOUNT;
+import static com.mybatisflex.test.table.Tables.ARTICLE;
 
 public class EntityTestStarter {
 
@@ -81,6 +82,16 @@ public class EntityTestStarter {
         Object object = accountMapper.selectObjectByQuery(wrapper2);
         System.out.println(object);
 
+        QueryWrapper asWrapper = QueryWrapper.create()
+                .select(ARTICLE.ALL_COLUMNS)
+                .select(ACCOUNT.USER_NAME,ACCOUNT.AGE,ACCOUNT.BIRTHDAY)
+                .from(ARTICLE)
+                .leftJoin(ACCOUNT).on(ARTICLE.ACCOUNT_ID.eq(ACCOUNT.ID))
+                .where(ACCOUNT.ID.ge(0));
+
+        List<ArticleDTO> articleDTOS = accountMapper.selectListByQueryAs(asWrapper, ArticleDTO.class);
+        System.out.println(articleDTOS);
+
 
 //        QueryWrapper queryWrapper = new QueryWrapper();
 //        queryWrapper.where(ACCOUNT.ID.in(