mybatis generator 自动生成的拼装sql分析
0.使用的场景
1.自己的实现: 一个简单的实现例子
2.成熟的解决方案: mybatis generator
3.源码分析
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java example
点击查看代码
public class JobLogExample { protected String orderByClause; protected boolean distinct; protected List<Criteria> oredCriteria; public JobLogExample() { oredCriteria = new ArrayList<Criteria>(); } public void setOrderByClause(String orderByClause) { this.orderByClause = orderByClause; } public String getOrderByClause() { return orderByClause; } public void setDistinct(boolean distinct) { this.distinct = distinct; } public boolean isDistinct() { return distinct; } public List<Criteria> getOredCriteria() { return oredCriteria; } public void or(Criteria criteria) { oredCriteria.add(criteria); } public Criteria or() { Criteria criteria = createCriteriaInternal(); oredCriteria.add(criteria); return criteria; } public Criteria createCriteria() { Criteria criteria = createCriteriaInternal(); if (oredCriteria.size() == 0) { oredCriteria.add(criteria); } return criteria; } protected Criteria createCriteriaInternal() { Criteria criteria = new Criteria(); return criteria; } public void clear() { oredCriteria.clear(); orderByClause = null; distinct = false; } protected abstract static class GeneratedCriteria { protected List<Criterion> criteria; protected GeneratedCriteria() { super(); criteria = new ArrayList<Criterion>(); } public boolean isValid() { return criteria.size() > 0; } public List<Criterion> getAllCriteria() { return criteria; } public List<Criterion> getCriteria() { return criteria; } protected void addCriterion(String condition) { if (condition == null) { throw new RuntimeException("Value for condition cannot be null"); } criteria.add(new Criterion(condition)); } protected void addCriterion(String condition, Object value, String property) { if (value == null) { throw new RuntimeException("Value for " + property + " cannot be null"); } criteria.add(new Criterion(condition, value)); } protected void addCriterion(String condition, Object value1, Object value2, String property) { if (value1 == null || value2 == null) { throw new RuntimeException("Between values for " + property + " cannot be null"); } criteria.add(new Criterion(condition, value1, value2)); } public Criteria andIdIsNull() { addCriterion("id is null"); return (Criteria) this; } public Criteria andIdIsNotNull() { addCriterion("id is not null"); return (Criteria) this; } public Criteria andIdEqualTo(Long value) { addCriterion("id =", value, "id"); return (Criteria) this; } public Criteria andIdNotEqualTo(Long value) { addCriterion("id <>", value, "id"); return (Criteria) this; } public Criteria andIdGreaterThan(Long value) { addCriterion("id >", value, "id"); return (Criteria) this; } public Criteria andIdGreaterThanOrEqualTo(Long value) { addCriterion("id >=", value, "id"); return (Criteria) this; } public Criteria andIdLessThan(Long value) { addCriterion("id <", value, "id"); return (Criteria) this; } public Criteria andIdLessThanOrEqualTo(Long value) { addCriterion("id <=", value, "id"); return (Criteria) this; } public Criteria andIdIn(List<Long> values) { addCriterion("id in", values, "id"); return (Criteria) this; } public Criteria andIdNotIn(List<Long> values) { addCriterion("id not in", values, "id"); return (Criteria) this; } public Criteria andIdBetween(Long value1, Long value2) { addCriterion("id between", value1, value2, "id"); return (Criteria) this; } public Criteria andIdNotBetween(Long value1, Long value2) { addCriterion("id not between", value1, value2, "id"); return (Criteria) this; } public Criteria andCreateTimeIsNull() { addCriterion("create_time is null"); return (Criteria) this; } public Criteria andCreateTimeIsNotNull() { addCriterion("create_time is not null"); return (Criteria) this; } public Criteria andCreateTimeEqualTo(Date value) { addCriterion("create_time =", value, "createTime"); return (Criteria) this; } public Criteria andCreateTimeNotEqualTo(Date value) { addCriterion("create_time <>", value, "createTime"); return (Criteria) this; } public Criteria andCreateTimeGreaterThan(Date value) { addCriterion("create_time >", value, "createTime"); return (Criteria) this; } public Criteria andCreateTimeGreaterThanOrEqualTo(Date value) { addCriterion("create_time >=", value, "createTime"); return (Criteria) this; } public Criteria andCreateTimeLessThan(Date value) { addCriterion("create_time <", value, "createTime"); return (Criteria) this; } public Criteria andCreateTimeLessThanOrEqualTo(Date value) { addCriterion("create_time <=", value, "createTime"); return (Criteria) this; } public Criteria andCreateTimeIn(List<Date> values) { addCriterion("create_time in", values, "createTime"); return (Criteria) this; } public Criteria andCreateTimeNotIn(List<Date> values) { addCriterion("create_time not in", values, "createTime"); return (Criteria) this; } public Criteria andCreateTimeBetween(Date value1, Date value2) { addCriterion("create_time between", value1, value2, "createTime"); return (Criteria) this; } public Criteria andCreateTimeNotBetween(Date value1, Date value2) { addCriterion("create_time not between", value1, value2, "createTime"); return (Criteria) this; } }
}
```
</details>
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java mapper
List<JobLog> selectByExample(JobLogExample example); int updateByExampleSelective(@Param("record") JobLogrecord, @Param("example") JobLogExample example); -
mybatis xml
Example_Where_Clause <sql id=""> <where> <foreach collection="oredCriteria" item="criteria" separator="or"> <if test="criteria.valid"> <trim prefix="(" prefixOverrides="and" suffix=")"> <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 close=")" collection="criterion.value" item="listItem" open="(" separator=","> #{listItem} </foreach> </when> </choose> </foreach> </trim> </if> </foreach> </where> </sql>Update_By_Example_Where_Clause <sql id="Update_By_Example_Where_Clause"> <where> <foreach collection="example.oredCriteria" item="criteria" separator="or"> <if test="criteria.valid"> <trim prefix="(" prefixOverrides="and" suffix=")"> <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 close=")" collection="criterion.value" item="listItem" open="(" separator=","> #{listItem} </foreach> </when> </choose> </foreach> </trim> </if> </foreach> </where> </sql>
4.常见的问题
