feat(优化抽象类AbstractMapper) 将for循环拼接的SQL语句改为Lambda表达式拼接，使得代码简洁清晰，并添加相关测试用例

plugin/datasource/src/main/java/com/alibaba/nacos/plugin/datasource/mapper/AbstractMapper.java

@@ -19,6 +19,7 @@
 import com.alibaba.nacos.common.utils.CollectionUtils;
 
 import java.util.List;
+import java.util.stream.Collectors;
 
 /**
  * The abstract mapper contains CRUD methods.
@@ -33,17 +34,9 @@ public String select(List<String> columns, List<String> where) {
         StringBuilder sql = new StringBuilder();
         String method = "SELECT ";
         sql.append(method);
-        for (int i = 0; i < columns.size(); i++) {
-            sql.append(columns.get(i));
-            if (i == columns.size() - 1) {
-                sql.append(" ");
-            } else {
-                sql.append(",");
-            }
-        }
-        sql.append("FROM ");
+        sql.append(columns.stream().collect(Collectors.joining(",")));
+        sql.append(" FROM ");
         sql.append(getTableName());
-        sql.append(" ");
 
         if (CollectionUtils.isEmpty(where)) {
             return sql.toString();
@@ -111,7 +104,6 @@ public String update(List<String> columns, List<String> where) {
             return sql.toString();
         }
 
-        sql.append(" ");
         appendWhereClause(where, sql);
 
         return sql.toString();
@@ -122,12 +114,7 @@ public String delete(List<String> params) {
         StringBuilder sql = new StringBuilder();
         String method = "DELETE ";
         sql.append(method).append("FROM ").append(getTableName()).append(" ").append("WHERE ");
-        for (int i = 0; i < params.size(); i++) {
-            sql.append(params.get(i)).append(" ").append("=").append(" ? ");
-            if (i != params.size() - 1) {
-                sql.append("AND ");
-            }
-        }
+        sql.append(params.stream().map(str -> (str + " = ?")).collect(Collectors.joining(" AND ")));
 
         return sql.toString();
     }
@@ -139,9 +126,8 @@ public String count(List<String> where) {
         sql.append(method);
         sql.append("COUNT(*) FROM ");
         sql.append(getTableName());
-        sql.append(" ");
 
-        if (null == where || where.size() == 0) {
+        if (CollectionUtils.isEmpty(where)) {
             return sql.toString();
         }
 
@@ -156,12 +142,7 @@ public String[] getPrimaryKeyGeneratedKeys() {
     }
 
     private void appendWhereClause(List<String> where, StringBuilder sql) {
-        sql.append("WHERE ");
-        for (int i = 0; i < where.size(); i++) {
-            sql.append(where.get(i)).append(" = ").append("?");
-            if (i != where.size() - 1) {
-                sql.append(" AND ");
-            }
-        }
+        sql.append(" WHERE ");
+        sql.append(where.stream().map(str -> (str + " = ?")).collect(Collectors.joining(" AND ")));
     }
 }

plugin/datasource/src/test/java/com/alibaba/nacos/plugin/datasource/mapper/AbstractMapperTest.java

@@ -49,9 +49,15 @@ public String getFunction(String functionName) {
             }
         };
     }
-
+
+    @Test
+    void testSelectSingleField() {
+        String sql = abstractMapper.select(Arrays.asList("id"), Arrays.asList("id"));
+        assertEquals("SELECT id FROM tenant_info WHERE id = ?", sql);
+    }
+
     @Test
-    void testSelect() {
+    public void testSelectMultiField() {
         String sql = abstractMapper.select(Arrays.asList("id", "name"), Arrays.asList("id"));
         assertEquals("SELECT id,name FROM tenant_info WHERE id = ?", sql);
     }
@@ -67,11 +73,17 @@ void testUpdate() {
         String sql = abstractMapper.update(Arrays.asList("id", "name"), Arrays.asList("id"));
         assertEquals("UPDATE tenant_info SET id = ?,name = ? WHERE id = ?", sql);
     }
-    
+
     @Test
-    void testDelete() {
+    public void testDeleteSingleField() {
         String sql = abstractMapper.delete(Arrays.asList("id"));
-        assertEquals("DELETE FROM tenant_info WHERE id = ? ", sql);
+        assertEquals("DELETE FROM tenant_info WHERE id = ?", sql);
+    }
+
+    @Test
+    public void testDeleteMultiField() {
+        String sql = abstractMapper.delete(Arrays.asList("id", "name"));
+        assertEquals("DELETE FROM tenant_info WHERE id = ? AND name = ?", sql);
     }
 
     @Test
@@ -89,12 +101,12 @@ void testGetPrimaryKeyGeneratedKeys() {
     @Test
     void testSelectAll() {
         String sql = abstractMapper.select(Arrays.asList("id", "name"), null);
-        assertEquals("SELECT id,name FROM tenant_info ", sql);
+        assertEquals("SELECT id,name FROM tenant_info", sql);
     }
 
     @Test
     void testCountAll() {
         String sql = abstractMapper.count(null);
-        assertEquals("SELECT COUNT(*) FROM tenant_info ", sql);
+        assertEquals("SELECT COUNT(*) FROM tenant_info", sql);
     }
 }