[英]how to read generated sql statement from annotation-configured Mybatis mapper
[英]How to specify IN param type with annotation-configured MyBatis
如果我想能够传递空值,似乎我需要明确告诉MyBatis用于java.util.Date IN参数的数据库类型。 但是我找不到这样做的方法。
我没有运气就尝试了以下各种变化:
@Select("<script>SELECT ... WHERE ... " +
"<if test='#{dateFrom,jdbcType=TIMESTAMP} != null'>" +
" AND date > #{dateFrom,jdbcType=TIMESTAMP}" +
"</if></script>")
List<MyType> getRecords(@Param("dateFrom") dateFrom)
使用注释时如何指定参数类型?
其他开发人员已经对这种问题发表了评论。
我引用GitHub评论:
@nglsatheesh MyBatis不能强制转换/转换这些类型,除非您告诉它如何。 您只需要一个简单的自定义类型处理程序。
public class StrToIntTypeHandler implements TypeHandler<String> {
@Override
public void setParameter(PreparedStatement ps, int i,
String parameter, JdbcType jdbcType) throws SQLException {
ps.setInt(i, Integer.parseInt(parameter));
}
// other methods are for binding query results.
}
从table_name中选择*,其中id =#{value,typeHandler = StrToIntTypeHandler}
所以现在,如果您要创建这样的自定义类型处理程序:
public class Null2DateTypeHandler implements TypeHandler<Date> {
@Override
public void setParameter(PreparedStatement ps, int i, java.util.Date parameter, JdbcType jdbcType) throws SQLException {
System.err.println(String.format("ps: %s, i: %d, param: %s, type: %s", ps.toString(), i, parameter, jdbcType.toString()));
if (parameter == null) {
ps.setDate(i, null); // ??? I'm not sure. But it works.
} else {
ps.setDate(i, new java.sql.Date(parameter.getTime()));
}
}
}
并且,映射器端:
@Select({
"<script>"
, "SELECT * FROM `employees` WHERE `hire_date` "
, " BETWEEN
, " #{dateFrom,typeHandler=*.*.*.Null2DateTypeHandler}"
, " AND"
, " #{dateTo,typeHandler=*.*.*.Null2DateTypeHandler}"
,"</script>"
})
@Results({
@Result(property = "empNo", column = "emp_no"),
@Result(property = "birthDate", column = "birth_date"),
@Result(property = "firstName", column = "first_name"),
@Result(property = "lastName", column = "last_name"),
@Result(property = "gender", column = "gender"),
@Result(property = "hireDate", column = "hire_date")
})
List<Employees> selectBetweenTypeHandler(@Param("dateFrom") Date dateFrom, @Param("dateTo") Date dateTo);
我的日志记录,看起来工作正常。
DEBUG [main] - ==> Preparing: SELECT * FROM `employees` WHERE `hire_date` BETWEEN ? AND ?
ps: org.apache.ibatis.logging.jdbc.PreparedStatementLogger@369f73a2, i: 1, param: null, type: OTHER
DEBUG [main] - ==> Parameters: null, null
ps: org.apache.ibatis.logging.jdbc.PreparedStatementLogger@369f73a2, i: 2, param: null, type: OTHER
DEBUG [main] - <== Total: 0
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