mybatis generator 的复合查询 博客分类： mybatis likemybatisgeneratorCriteria
mybatis generator可以自动生成sqlmap文件和查询语句，但是只能完成单表的查询，自己改了下，可以实现复合查询，感觉能比自己写查询语句能方便一些吧。
下面就讲讲怎么改的，和主要区别。
先说下表结构，主表stockclothestbl，副表有很多，那其中一个colortbl表举例。
正常通过generator可以自动生成StockclothestblExample.java，ColortblExample.java和StockclothestblMapper.xml，ColortblMapper.xml，4个文件。StockclothestblExample.java和ColortblExample.java文件用于查询。新建StockclothesExample.java。用于包含2个查询对象。
public class StockclothesExample {
public StockclothestblExample stockclothestblExample;
public ColortblExample colortblExample;
public StockclothestblExample getStockclothestblExample() {
return stockclothestblExample;
}
public void setStockclothestblExample(StockclothestblExample stockclothestblExample) {
this.stockclothestblExample = stockclothestblExample;
}
public ColortblExample getColortblExample() {
return colortblExample;
}
public void setColortblExample(ColortblExample colortblExample) {
this.colortblExample = colortblExample;
}
}
然后开始修改StockclothestblMapper.xml和ColortblMapper.xml文件
StockclothestblMapper.xml 文件里，添加sql,仿照自动生成的单表查询。
<!-- 联合查询 -->
<select id="selectStockclothes" resultMap="selectStockclothesResult" parameterType="cn.com.shopdepot.javaModel.custom.StockclothesExample">
select
<if test="stockclothestblExample.distinct" >
distinct
</if>
<include refid="cn.com.shopdepot.javaClient.StockclothestblMapper.Base_Column_List" />
,
<include refid="cn.com.shopdepot.javaClient.RegisterdepottblMapper.Base_Column_List" />
,
<include refid="cn.com.shopdepot.javaClient.StyletblMapper.Base_Column_List" />
,
<include refid="cn.com.shopdepot.javaClient.KindtblMapper.Base_Column_List" />
,
<include refid="cn.com.shopdepot.javaClient.ClotheskindtblMapper.Base_Column_List" />
,
<include refid="cn.com.shopdepot.javaClient.ColortblMapper.Base_Column_List" />
,
<include refid="cn.com.shopdepot.javaClient.SizetblMapper.Base_Column_List"/>
from stockclothestbl stockclothestbl
left join registerdepottbl registerdepottbl on registerdepottbl.REGISTERDEPOT_SERNO=stockclothestbl.REGISTERDEPOT_SERNO
left join styletbl styletbl on styletbl.STYLE=stockclothestbl.STYLE
left join kindtbl kindtbl on kindtbl.KIND=stockclothestbl.KIND
left join clotheskindtbl clotheskindtbl on clotheskindtbl.CLOTHESKIND_CODE=stockclothestbl.CLOTHESKIND_CODE
left join colortbl colortbl on colortbl.COLOR_SERNO=stockclothestbl.COLOR_SERNO
left join sizetbl sizetbl on sizetbl.SIZE_CODE=stockclothestbl.SIZE_CODE
and styletbl.DEL_FLAG='0'
and kindtbl.DEL_FLAG='0'
and clotheskindtbl.DEL_FLAG='0'
and colortbl.DEL_FLAG='0'
and sizetbl.DEL_FLAG='0'
<if test="_parameter != null" >
<where>
<trim prefix="(" suffix=")" prefixOverrides="and" >
<include refid="cn.com.shopdepot.javaClient.StockclothestblMapper.Example_Where_Clause_Complex" />
<include refid="cn.com.shopdepot.javaClient.ColortblMapper.Example_Where_Clause_Complex"/>
</trim>
</where>
</if>
<if test="stockclothestblExample.orderByClause != null" >
order by ${stockclothestblExample.orderByClause}
</if>
<include refid="cn.com.shopdepot.javaClient.StockclothestblMapper.mysqlDialect_Complex" />
</select>
解释下这个sql
id="selectStockclothes",是以后java端调用的方法名。
resultMap="selectStockclothesResult" 这个是返回结果，引用selectStockclothesResult，下面是selectStockclothesResult
<resultMap type="cn.com.shopdepot.javaModel.custom.Stockclothes" id="selectStockclothesResult">
<association property="stockclothestbl" resultMap="cn.com.shopdepot.javaClient.StockclothestblMapper.BaseResultMap"></association>
<association property="registerdepottbl" resultMap="cn.com.shopdepot.javaClient.RegisterdepottblMapper.BaseResultMap"></association>
<association property="styletbl" resultMap="cn.com.shopdepot.javaClient.StyletblMapper.BaseResultMap"></association>
<association property="kindtbl" resultMap="cn.com.shopdepot.javaClient.KindtblMapper.BaseResultMap"></association>
<association property="clotheskindtbl" resultMap="cn.com.shopdepot.javaClient.ClotheskindtblMapper.BaseResultMap"></association>
<association property="colortbl" resultMap="cn.com.shopdepot.javaClient.ColortblMapper.BaseResultMap"></association>
<association property="sizetbl" resultMap="cn.com.shopdepot.javaClient.SizetblMapper.BaseResultMap"></association>
</resultMap>
其中 <association property="colortbl" resultMap="cn.com.shopdepot.javaClient.ColortblMapper.BaseResultMap"></association>
就是ColortblMapper.xml文件中最上边的命名空间+ColortblMapper.xml文件中BaseResultMap的id。
继续上边，parameterType="cn.com.shopdepot.javaModel.custom.StockclothesExample" 参数就是我们自己添加的StockclothesExample.java文件的全路径。
<if test="stockclothestblExample.distinct" >，这个地方要修改，原来自动生成的是<if test="distinct" >修改成
<if test="stockclothestblExample.distinct" >。这样才能反射找到是stockclothestblExample对象里的distinct。
stockclothestblExample---是我们自己添加StockclothesExample类里的成员
<include refid="cn.com.shopdepot.javaClient.ColortblMapper.Base_Column_List" />，这个同理resultMap的，查询sql的字段，colortbl表的字段。
下面修改的相对比较多
<if test="_parameter != null" >
<where>
<trim prefix="(" suffix=")" prefixOverrides="and" >
<include refid="cn.com.shopdepot.javaClient.StockclothestblMapper.Example_Where_Clause_Complex" />
<include refid="cn.com.shopdepot.javaClient.ColortblMapper.Example_Where_Clause_Complex"/>
</trim>
</where>
</if>
自动生成的单表查询的以前的下面
<if test="_parameter != null" >
<include refid="Example_Where_Clause" />
</if>
添加了colortbl的查询 <include refid="cn.com.shopdepot.javaClient.ColortblMapper.Example_Where_Clause_Complex"/>
以前的refid="Example_Where_Clause"------变成Example_Where_Clause_Complex，Example_Where_Clause是自动生成的，
Example_Where_Clause_Complex是我自己添加的，仿照Example_Where_Clause。下面是2个表的Example_Where_Clause_Complex。
分别写在2个自己的xml中。
StockclothestblMapper.xml添加的Example_Where_Clause_Complex
<sql id="Example_Where_Clause_Complex" >
<foreach collection="stockclothestblExample.oredCriteria" item="criteria" separator="or" >
<if test="criteria.valid" >
<foreach collection="criteria.criteria" item="criterion" >
<choose >
<when test="criterion.noValue" >
and ${criterion.condition}
</when>
<when test="criterion.singleValue" >
and ${criterion.condition} #{criterion.value}
</when>
<when test="criterion.betweenValue" >
and ${criterion.condition} #{criterion.value} and #{criterion.secondValue}
</when>
<when test="criterion.listValue" >
and ${criterion.condition}
<foreach collection="criterion.value" item="listItem" open="(" close=")" separator="," >
#{listItem}
</foreach>
</when>
</choose>
</foreach>
</if>
</foreach>
</sql>
StockclothestblMapper.xml自动生成的Example_Where_Clause
<sql id="Example_Where_Clause" >
<where >
<foreach collection="oredCriteria" item="criteria" separator="or" >
<if test="criteria.valid" >
<trim prefix="(" suffix=")" prefixOverrides="and" >
<foreach collection="criteria.criteria" item="criterion" >
<choose >
<when test="criterion.noValue" >
and ${criterion.condition}
</when>
<when test="criterion.singleValue" >
and ${criterion.condition} #{criterion.value}
</when>
<when test="criterion.betweenValue" >
and ${criterion.condition} #{criterion.value} and #{criterion.secondValue}
</when>
<when test="criterion.listValue" >
and ${criterion.condition}
<foreach collection="criterion.value" item="listItem" open="(" close=")" separator="," >
#{listItem}
</foreach>
</when>
</choose>
</foreach>
</trim>
</if>
</foreach>
</where>
</sql>
比较看下，红色的去修改的，去掉where和trim，因为2个要在最外层加，上边画的蓝色部分。
collection="oredCriteria"变成collection="stockclothestblExample.oredCriteria"，因为你的指定到你的类的具体对象。
同上
ColortblMapper.xml 添加的Example_Where_Clause_Complex
<sql id="Example_Where_Clause_Complex" >
<foreach collection="colortblExample.oredCriteria" item="criteria" separator="or" >
<if test="criteria.valid" >
<foreach collection="criteria.criteria" item="criterion" >
<choose >
<when test="criterion.noValue" >
and ${criterion.condition}
</when>
<when test="criterion.singleValue" >
and ${criterion.condition} #{criterion.value}
</when>
<when test="criterion.betweenValue" >
and ${criterion.condition} #{criterion.value} and #{criterion.secondValue}
</when>
<when test="criterion.listValue" >
and ${criterion.condition}
<foreach collection="criterion.value" item="listItem" open="(" close=")" separator="," >
#{listItem}
</foreach>
</when>
</choose>
</foreach>
</if>
</foreach>
</sql>
ColortblMapper.xml自动生成的Example_Where_Clause
<sql id="Example_Where_Clause" >
<where >
<foreach collection="oredCriteria" item="criteria" separator="or" >
<if test="criteria.valid" >
<trim prefix="(" suffix=")" prefixOverrides="and" >
<foreach collection="criteria.criteria" item="criterion" >
<choose >
<when test="criterion.noValue" >
and ${criterion.condition}
</when>
<when test="criterion.singleValue" >
and ${criterion.condition} #{criterion.value}
</when>
<when test="criterion.betweenValue" >
and ${criterion.condition} #{criterion.value} and #{criterion.secondValue}
</when>
<when test="criterion.listValue" >
and ${criterion.condition}
<foreach collection="criterion.value" item="listItem" open="(" close=")" separator="," >
#{listItem}
</foreach>
</when>
</choose>
</foreach>
</trim>
</if>
</foreach>
</where>
</sql>
继续上边的解释
<if test="stockclothestblExample.orderByClause != null" >
order by ${stockclothestblExample.orderByClause}
</if>
也是指定到具体对象的排序，绿色部分。
sqlmap基本就改完了，剩下没解释的，是分页limit，就不解释了，贴一下代码
<sql id="mysqlDialect_Complex" >
<if test="stockclothestblExample.limitStart > -1">
limit ${stockclothestblExample.limitStart}, ${stockclothestblExample.limitEnd}
</if>
</sql>
以上基本就完成了。
然后在自动生成的StockclothestblMapper.java，添加方法
/**
* sqlmap id=selectStockclothes
*
* @author wang
* @param example
* @return
*/
List<Stockclothes> selectStockclothes(StockclothesExample example);
这样就可以使用了。大概写下
StockclothesExample example = new StockclothesExample();
StockclothestblExample stockclothestblExample = new StockclothestblExample();
StockclothestblExample.Criteria stockclothestbl_criteria = stockclothestblExample.createCriteria();
ColortblExample colortblExample = new ColortblExample();
ColortblExample.Criteria colortbl_criteria = colortblExample.createCriteria();
if (null != selBrand && !"".equals(selBrand)) {
stockclothestbl_criteria.andBrandLike("%" + selBrand + "%");
}
if (null != selColor && !"".equals(selColor)) {
colortbl_criteria.andColorLike("%" + selColor + "%");
}
example.setStockclothestblExample(stockclothestblExample)；
example.setColortblExample(colortblExample);
..... 中间省略.......
List <Stockclothes>list=stockclothestblMapper.selectStockclothes(example)
Stockclothes类封装的genertor自动生成的tbl
结束！
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