MyBatis學習筆記之四--annotation註解
阿新 • • 發佈：2018-12-13
使用MyBatis註解開發，可以省去類配置檔案，簡潔方便。但是比較複雜的SQL和動態SQL還是建議書寫類配置檔案。
註解還是不推薦使用的。只是瞭解瞭解！簡單的CRUD可以使用註解。簡單寫寫。
把之前的例子改成使用註解的。
UserMapper.java
1 package com.cy.mybatis.mapper;
2
3 import java.util.List;
4 import java.util.Map;
5
6 import org.apache.ibatis.annotations.Delete;
7 import org.apache.ibatis.annotations.Insert;
8 import org.apache.ibatis.annotations.Options;
9 import org.apache.ibatis.annotations.Param;
10 import org.apache.ibatis.annotations.Result;
11 import org.apache.ibatis.annotations.ResultMap;
12 import org.apache.ibatis.annotations.Results;
13 import org.apache.ibatis.annotations.Select;
14 import org.apache.ibatis.annotations.Update;
15
16 import com.cy.mybatis.beans.UserBean;
17
18 public interface UserMapper {
19 // 簡單的增刪改查可以使用註解
20 // 註解+配置檔案
21
22 /**
23 * 新增使用者
24 * @param user
25 * @return
26 * @throws Exception
27 */
28 @Insert("insert into t_user value (null,user.username,user.password,user.account)")
29 @Options(useGeneratedKeys=true,keyProperty="user.id")
30 public int insertUser(@Param("user")UserBean user) throws Exception;
31
32
33 /**
34 * 修改使用者
35 * @param user
36 * @param id
37 * @return
38 * @throws Exception
39 */
40 @Update(" update t_user set username=#{u.username},password=#{u.password},account=#{u.account} where id=#{id}")
41 public int updateUser (@Param("u")UserBean user,@Param("id")int id) throws Exception;
42
43 /**
44 * 刪除使用者
45 * @param id
46 * @return
47 * @throws Exception
48 */
49 @Delete(" delete from t_user where id=#{id} ")
50 public int deleteUser(int id) throws Exception;
51
52
53 /**
54 * 根據id查詢使用者資訊
55 * @param id
56 * @return
57 * @throws Exception
58 */
59
60 @Select(" select * from t_user where id=#{id}")
61 @Results({
62
63 @Result(id=true,property="id",column="id",javaType=Integer.class),
64 @Result(property="username",column="username",javaType=String.class),
65 @Result(property="password",column="password",javaType=String.class),
66 @Result(property="account",column="account",javaType=Double.class)
67 })
68 public UserBean selectUserById(int id) throws Exception;
69 /**
70 * 查詢所有的使用者資訊
71 * @return
72 * @throws Exception
73 */
74
75 @Select(" select * from t_user")
76 @ResultMap("userMap")
77 public List<UserBean> selectAllUser() throws Exception;
78
79
80 /**
81 * 批量增加
82 * @param user
83 * @return
84 * @throws Exception
85 */
86 public int batchInsertUser(@Param("users")List<UserBean> user) throws Exception;
87
88 /**
89 * 批量刪除
90 * @param list
91 * @return
92 * @throws Exception
93 */
94 public int batchDeleteUser(@Param("list")List<Integer> list) throws Exception;
95
96
97 /**
98 * 分頁查詢資料
99 * @param parma
100 * @return
101 * @throws Exception
102 */
103 public List<UserBean> pagerUser(Map<String, Object> parmas) throws Exception;
104
105 /**
106 *
107 * 分頁統計資料
108 * @param parma
109 * @return
110 * @throws Exception
111 */
112 public int countUser(Map<String, Object> parmas) throws Exception;
113
114 }
UserMapper.xml
1 <?xml version="1.0" encoding="UTF-8"?>
2 <!DOCTYPE mapper PUBLIC "-//mybatis.org/DTD Mapper 3.0" "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
3 <mapper namespace="com.cy.mybatis.mapper.UserMapper">
4 <!-- 自定義返回結果集 -->
5 <resultMap id="userMap" type="UserBean">
6 <id property="id" column="id" javaType="java.lang.Integer"></id>
7 <result property="username" column="username" javaType="java.lang.String"></result>
8 <result property="password" column="password" javaType="java.lang.String"></result>
9 <result property="account" column="account" javaType="java.lang.Double"></result>
10 </resultMap>
11
12 <!-- 批量操作和foreach標籤 -->
13
14 <insert id="batchInsertUser" parameterType="java.util.List">
15 insert into t_user values
16 <foreach collection="users" item="users" separator=",">
17 (null,#{users.username},#{users.password},#{users.account})
18 </foreach>
19 </insert>
20
21
22 <delete id="batchDeleteUser">
23 delete from t_user where id in (
24 <foreach collection="list" item="list" separator=",">
25 #{id}
26 </foreach>
27 )
28 </delete>
29
30 <!--collection 為用於遍歷的元素（必選），支援陣列、List、Set -->
31 <!-- item 表示集合中每一個元素進行迭代時的別名. -->
32 <!--separator表示在每次進行迭代之間以什麼符號作為分隔 符. -->
33
34 <!--#在生成SQL時，對於字元型別引數，會拼裝引號
35 $在生成SQL時，不會拼裝引號，可用於order by之類的引數拼裝
36 -->
37 <select id="pagerUser" parameterType="java.util.Map" resultMap="userMap">
38 select * from t_user where 1=1
39 <if test="username!=null">
40 and username like '%${username}%'
41 </if>
42 limit ${index},${pageSize}
43 </select>
44
45 <select id="countUser" parameterType="java.util.Map" resultType="int">
46 select count(*) from t_user where 1=1
47 <if test="username != null">
48 and username like '%${username}%'
49 </if>
50 </select>
51
52 </mapper>
簡單的一個一對一的使用註解的。
1 package com.lovo.mybatis.mapper;
2
3 import org.apache.ibatis.annotations.Insert;
4 import org.apache.ibatis.annotations.One;
5 import org.apache.ibatis.annotations.Options;
6 import org.apache.ibatis.annotations.Param;
7 import org.apache.ibatis.annotations.Result;
8 import org.apache.ibatis.annotations.ResultType;
9 import org.apache.ibatis.annotations.Results;
10 import org.apache.ibatis.annotations.Select;
11
12 import com.lovo.mybatis.beans.HusbandBean;
13 import com.lovo.mybatis.beans.WifeBean;
14
15 public interface HusbandMapper {
16
17 /**
18 * 儲存丈夫
19 * @param husband
20 * @return
21 */
22 @Insert("insert into t_husband values (null,#{h.name})")
23 @Options(useGeneratedKeys=true,keyProperty="h.id")
24 public int saveHusband(@Param("h")HusbandBean husband);
25
26
27 /**
28 * 根據ID查詢丈夫資料
29 * @param id
30 * @return
31 */
32 @Select("select * from t_husband where id=#{id}")
33 @ResultType(HusbandBean.class)
34 public HusbandBean findHusbandById(int id);
35
36
37
38 /**
39 * 根據ID查詢丈夫與妻子資料
40 * @param id
41 * @return
42 */
43 @Select("select * from t_husband where id=#{id}")
44 @Results({
45 @Result(id=true,property="id",column="id",javaType=Integer.class),
46 @Result(property="name",column="name",javaType=String.class),
47 @Result(property="wife",column="id",javaType=WifeBean.class,
1 package com.cy.mybatis.mapper;
2
3 import org.apache.ibatis.annotations.ResultType;
4 import org.apache.ibatis.annotations.Select;
5
6 import com.cy.mybatis.beans.WifeBean;
7
8 public interface WifeMapper {
9
10
11 @Select("select * from t_wife where fk_husband_id = #{id}")
12 @ResultType(WifeBean.class)
13 public WifeBean selectWifeByHusbandId(int id)throws Exception;
14
15 }
注意：使用resultType時，一定要保證，你屬性名與欄位名相同；如果不相同，就使用resultMap 。