Mybatis传参总结

mybatis中手动写sql，步骤是先在navicate中执行通过的sql，

如果是对象类型传参，需要注意jdbcType转换，比如：name = #{record.name,jdbcType=VARCHAR}

以下几种方法比较常用，欢迎补充。

1.pom.xml中mybatis依赖1.2.0

<dependencies>

 <dependency>

<groupId>org.mybatis.spring.boot</groupId>

<artifactId>mybatis-spring-boot-starter</artifactId>

<version>1.2.0</version>

<exclusions>

<exclusion>

<groupId>org.apache.tomcat</groupId>

<artifactId>tomcat-jdbc</artifactId>

</exclusion>

</exclusions>

</dependency>


<dependency>

<groupId>com.zaxxer</groupId>

<artifactId>HikariCP</artifactId>

</dependency>

<dependency>

<groupId>com.github.pagehelper</groupId>

<artifactId>pagehelper-spring-boot-starter</artifactId>

<version>1.1.1</version>

</dependency>


<dependency>

<groupId>mysql</groupId>

<artifactId>mysql-connector-java</artifactId>

</dependency>

</dependencies>


<build>

<plugins>

<plugin>

<groupId>org.mybatis.generator</groupId>

<artifactId>mybatis-generator-maven-plugin</artifactId>

<version>1.3.2</version>

<configuration>

<overwrite>true</overwrite>

<verbose>true</verbose>

</configuration>

</plugin>

</plugins>

</build>

2.基本类型和对象参数，可以是这样：

ServerMapper.java:

int updateByExample(@Param("record") Server record, @Param("example") ServerExample example);

ServerMapper.xml:

<update id="updateByExample" parameterType="map">

update server

set id = #{record.id,jdbcType=VARCHAR},

name = #{record.name,jdbcType=VARCHAR},

operatingsystem = #{record.operatingsystem,jdbcType=VARCHAR},

cpu = #{record.cpu,jdbcType=INTEGER},

applicant = #{record.applicant,jdbcType=VARCHAR},

status = #{record.status,jdbcType=VARCHAR}

<if test="_parameter != null">

<include refid="Update_By_Example_Where_Clause" />

</if>

</update>

ServerMapper.java:

List<ServerDetails> selectByServerIds(List<String> serverIds);

ServerMapper.xml，注意collection为list:

<select id="selectByServerIds" resultMap="ServerDetailsMap">


SELECT s.id, s.`name`,s.operatingsystem,s.cpu,s.disksize,s.memorysize,s.intranetip,s.vcluster,s.`owner`,s.environment,s.applicant,s.`status`,

ip.ip,ip.`status` as ipstatus, ip.segment,ip.remark,ip.line

from `server` as s , ippool as ip

where s.intranetip = ip.id

and s.id in

<foreach item="item" collection="list" open="(" separator="," close=")">

#{item}

</foreach>

</select>

可以传递一个 List 实例或者数组作为参数对象传给 MyBatis。

当你这么做的时,MyBatis 会自动将它包装在一个 Map 中,用名称作为key。List 实例将会以“list” 作为key,而数组实例将会以“array”作为key。

ServerMapper.java文件中传入的是包含list的map，ServerMapper.xml中的collection为指定的excRelatedServerIds

Map<String, Object> map = Maps.newHashMap();

map.put("env", env);

map.put("userId", userId);

map.put("excRelatedServerIds", excRelatedServerIds);

PageInfo<UserServerDetails> pageInfo = PageHelper.startPage(pageNum, pageSize).doSelectPageInfo(()-> serverMapper.selectPageByEnvAndUserExcRelated(map));

ServerMapper.xml：

 select us.id, us.user_id, us.server_id,

s.`name`, s.operatingsystem, s.cpu,s.disksize,s.memorysize, s.intranetip, s.vcluster,s.`owner`,s.environment,s.applicant,s.`status`,

ip.ip,ip.`status` as ipstatus,ip.segment,ip.remark , ip.line

from user_server as us,`server` as s, ippool as ip

where us.server_id = s.id and s.intranetip = ip.id

<if test="env != null">

and s.environment=#{env,jdbcType=INTEGER}

</if>


<if test="userId != null">

and us.user_id=#{userId,jdbcType=VARCHAR}

</if>


and s.id not in

<foreach item="item" index="index" collection="excRelatedServerIds" open="(" separator="," close=")">

#{item}

</foreach>

</select>

5.还有一种是按照顺序传参数，这种不推荐：

Mapper.java：

Public User selectUser(String name,String area);

Mapper.xml ：

<select id="selectUser" resultMap="BaseResultMap">

select * from user_user_t where user_name = #{0} and user_area=#{1}

</select> 其中，#{0}代表接收的是dao层中的第一个参数，#{1}代表dao层中第二参数，更多参数一致往后加即可。

6.如果要封装自己的返回类型，需要xml文件中定义并且去引用bean对象：

<resultMap id="ServerDetailsMap" type="com.ServerDetails">

<id column="id" property="id" jdbcType="VARCHAR" />

<result column="name" jdbcType="VARCHAR" property="name" />

<result column="operatingsystem" jdbcType="VARCHAR" property="operatingsystem" />

<result column="cpu" jdbcType="INTEGER" property="cpu" />

<result column="disksize" jdbcType="INTEGER" property="disksize" />

<result column="memorysize" jdbcType="INTEGER" property="memorysize" />

<result column="intranetip" jdbcType="VARCHAR" property="intranetip" />

<result column="vcluster" jdbcType="VARCHAR" property="vcluster" />

<result column="owner" jdbcType="VARCHAR" property="owner" />

<result column="environment" jdbcType="INTEGER" property="environment" />

<result column="applicant" jdbcType="VARCHAR" property="applicant" />

<result column="status" jdbcType="VARCHAR" property="status" />

</resultMap>

mybatis ${}与#{}的区别(来源网络)

然而${} 则是不能防止SQL注入打印出来的语句 select *　from table where id=2 实实在在的参数。

最简单的区别就是${}解析传过来的参数值不带单引号，#{}解析传过来参数带单引号。