实现通过指定id查询

ffms-MyBatisProject/src/com/ssm/mapper/DictMapper.java

@@ -1,5 +1,6 @@
 package com.ssm.mapper;
 
+import com.ssm.entity.Budget;
 import com.ssm.entity.Dict;
 import java.util.List;
 
@@ -16,4 +17,5 @@ public interface DictMapper {
     Dict getDictById(Integer dictId);
 
     List<Dict> listDict(String dictType);
+    Dict selectDictById(Integer dictId);
 }

ffms-MyBatisProject/src/com/ssm/mapper/DictMapper.xml

@@ -53,5 +53,9 @@
         FROM dict
         WHERE is_valid = 'Y'
     </select>
+    <!--    查询指定id-->
+    <select id="selectDictById" parameterType="int" resultType="com.ssm.entity.Dict">
+        SELECT * FROM dict WHERE dict_id = #{dictId}
+    </select>
 
 </mapper>

ffms-MyBatisProject/src/com/ssm/test/DictTest.java

@@ -19,6 +19,8 @@ public class DictTest {
 
         // 2. 按类型查询字典项（可选，和你的业务匹配）
         // testGetDictsByType();
+        //3.按id查询
+        testGetDictById();
     }
 
 
@@ -58,6 +60,22 @@ public class DictTest {
             System.out.println(dict);
         }
 
+        session.close();
+    }
+    //按id查询
+    private static void testGetDictById() throws IOException {
+        Reader reader = Resources.getResourceAsReader("config.xml");
+        SqlSessionFactory factory = new SqlSessionFactoryBuilder().build(reader);
+        SqlSession session = factory.openSession();
+
+        DictMapper mapper = session.getMapper(DictMapper.class);
+
+        // 查询 id = 1 的预算
+        Dict dict = mapper.selectDictById(1);
+
+        System.out.println("\n===== 根据ID查询预算 =====");
+        System.out.println(dict);
+
         session.close();
     }
 }