相关知识,可以参考
https://blog.csdn.net/chenbaige/article/details/72568959
这里,主要是说明TypeHandler的生效顺序的。
public TypeHandlerRegistry() {
this.register((Class)Boolean.class, (TypeHandler)(new BooleanTypeHandler()));
this.register((Class)Boolean.TYPE, (TypeHandler)(new BooleanTypeHandler()));
this.register((JdbcType)JdbcType.BOOLEAN, (TypeHandler)(new BooleanTypeHandler()));
this.register((JdbcType)JdbcType.BIT, (TypeHandler)(new BooleanTypeHandler()));
this.register((Class)Byte.class, (TypeHandler)(new ByteTypeHandler()));
this.register((Class)Byte.TYPE, (TypeHandler)(new ByteTypeHandler()));
this.register((JdbcType)JdbcType.TINYINT, (TypeHandler)(new ByteTypeHandler()));
this.register((Class)Short.class, (TypeHandler)(new ShortTypeHandler()));
this.register((Class)Short.TYPE, (TypeHandler)(new ShortTypeHandler()));
this.register((JdbcType)JdbcType.SMALLINT, (TypeHandler)(new ShortTypeHandler()));
this.register((Class)Integer.class, (TypeHandler)(new IntegerTypeHandler()));
this.register((Class)Integer.TYPE, (TypeHandler)(new IntegerTypeHandler()));
this.register((JdbcType)JdbcType.INTEGER, (TypeHandler)(new IntegerTypeHandler()));
this.register((Class)Long.class, (TypeHandler)(new LongTypeHandler()));
this.register((Class)Long.TYPE, (TypeHandler)(new LongTypeHandler()));
this.register((Class)Float.class, (TypeHandler)(new FloatTypeHandler()));
this.register((Class)Float.TYPE, (TypeHandler)(new FloatTypeHandler()));
this.register((JdbcType)JdbcType.FLOAT, (TypeHandler)(new FloatTypeHandler()));
this.register((Class)Double.class, (TypeHandler)(new DoubleTypeHandler()));
this.register((Class)Double.TYPE, (TypeHandler)(new DoubleTypeHandler()));
this.register((JdbcType)JdbcType.DOUBLE, (TypeHandler)(new DoubleTypeHandler()));
this.register((Class)Reader.class, (TypeHandler)(new ClobReaderTypeHandler()));
this.register((Class)String.class, (TypeHandler)(new StringTypeHandler()));
this.register((Class)String.class, JdbcType.CHAR, (TypeHandler)(new StringTypeHandler()));
this.register((Class)String.class, JdbcType.CLOB, (TypeHandler)(new ClobTypeHandler()));
this.register((Class)String.class, JdbcType.VARCHAR, (TypeHandler)(new StringTypeHandler()));
this.register((Class)String.class, JdbcType.LONGVARCHAR, (TypeHandler)(new ClobTypeHandler()));
this.register((Class)String.class, JdbcType.NVARCHAR, (TypeHandler)(new NStringTypeHandler()));
this.register((Class)String.class, JdbcType.NCHAR, (TypeHandler)(new NStringTypeHandler()));
this.register((Class)String.class, JdbcType.NCLOB, (TypeHandler)(new NClobTypeHandler()));
this.register((JdbcType)JdbcType.CHAR, (TypeHandler)(new StringTypeHandler()));
this.register((JdbcType)JdbcType.VARCHAR, (TypeHandler)(new StringTypeHandler()));
this.register((JdbcType)JdbcType.CLOB, (TypeHandler)(new ClobTypeHandler()));
this.register((JdbcType)JdbcType.LONGVARCHAR, (TypeHandler)(new ClobTypeHandler()));
this.register((JdbcType)JdbcType.NVARCHAR, (TypeHandler)(new NStringTypeHandler()));
this.register((JdbcType)JdbcType.NCHAR, (TypeHandler)(new NStringTypeHandler()));
this.register((JdbcType)JdbcType.NCLOB, (TypeHandler)(new NClobTypeHandler()));
this.register((Class)Object.class, JdbcType.ARRAY, (TypeHandler)(new ArrayTypeHandler()));
this.register((JdbcType)JdbcType.ARRAY, (TypeHandler)(new ArrayTypeHandler()));
this.register((Class)BigInteger.class, (TypeHandler)(new BigIntegerTypeHandler()));
this.register((JdbcType)JdbcType.BIGINT, (TypeHandler)(new LongTypeHandler()));
this.register((Class)BigDecimal.class, (TypeHandler)(new BigDecimalTypeHandler()));
this.register((JdbcType)JdbcType.REAL, (TypeHandler)(new BigDecimalTypeHandler()));
this.register((JdbcType)JdbcType.DECIMAL, (TypeHandler)(new BigDecimalTypeHandler()));
this.register((JdbcType)JdbcType.NUMERIC, (TypeHandler)(new BigDecimalTypeHandler()));
this.register((Class)InputStream.class, (TypeHandler)(new BlobInputStreamTypeHandler()));
this.register((Class)Byte[].class, (TypeHandler)(new ByteObjectArrayTypeHandler()));
this.register((Class)Byte[].class, JdbcType.BLOB, (TypeHandler)(new BlobByteObjectArrayTypeHandler()));
this.register((Class)Byte[].class, JdbcType.LONGVARBINARY, (TypeHandler)(new BlobByteObjectArrayTypeHandler()));
this.register((Class)byte[].class, (TypeHandler)(new ByteArrayTypeHandler()));
this.register((Class)byte[].class, JdbcType.BLOB, (TypeHandler)(new BlobTypeHandler()));
this.register((Class)byte[].class, JdbcType.LONGVARBINARY, (TypeHandler)(new BlobTypeHandler()));
this.register((JdbcType)JdbcType.LONGVARBINARY, (TypeHandler)(new BlobTypeHandler()));
this.register((JdbcType)JdbcType.BLOB, (TypeHandler)(new BlobTypeHandler()));
this.register(Object.class, this.UNKNOWN_TYPE_HANDLER);
this.register(Object.class, JdbcType.OTHER, this.UNKNOWN_TYPE_HANDLER);
this.register(JdbcType.OTHER, this.UNKNOWN_TYPE_HANDLER);
this.register((Class)Date.class, (TypeHandler)(new DateTypeHandler()));
this.register((Class)Date.class, JdbcType.DATE, (TypeHandler)(new DateOnlyTypeHandler()));
this.register((Class)Date.class, JdbcType.TIME, (TypeHandler)(new TimeOnlyTypeHandler()));
this.register((JdbcType)JdbcType.TIMESTAMP, (TypeHandler)(new DateTypeHandler()));
this.register((JdbcType)JdbcType.DATE, (TypeHandler)(new DateOnlyTypeHandler()));
this.register((JdbcType)JdbcType.TIME, (TypeHandler)(new TimeOnlyTypeHandler()));
this.register((Class)java.sql.Date.class, (TypeHandler)(new SqlDateTypeHandler()));
this.register((Class)Time.class, (TypeHandler)(new SqlTimeTypeHandler()));
this.register((Class)Timestamp.class, (TypeHandler)(new SqlTimestampTypeHandler()));
if (Jdk.dateAndTimeApiExists) {
Java8TypeHandlersRegistrar.registerDateAndTimeHandlers(this);
}
this.register((Class)Character.class, (TypeHandler)(new CharacterTypeHandler()));
this.register((Class)Character.TYPE, (TypeHandler)(new CharacterTypeHandler()));
}
项目中,新注册了一个BooleanTypeHandler,用于将boolean类型的值转化成字符串TRUE或FALSE。但是在查询时,总是会报错,原因是在查询语句中,没有指定属性的jdbcType,所以mybatis使用了默认的处理类。这里,执行查询字段的jdbcType类型即可解决。
Map<String,Object> param = new HashMap<>(); param.put("booleantest",Boolean.TRUE);
<select id="selectUser" parameterType="map" resultMap="BaseResultMap">
select * from user
<where>
1 = 1
<if test="name != null">
and name = #{name}
</if>
<if test="code != null">
and code = #{code}
</if>
<if test="booleantest != null">
and booleantest = #{booleantest,jdbcType=VARCHAR}
</if>
</where>
</select>