识字粗堪供赋役,不须辛苦慕公卿。这篇文章主要讲述扩展mybatis和通用mapper,支持mysql的geometry类型字段相关的知识,希望能为你提供帮助。
因项目中需要用到地理位置信息的存储、查询、计算等,经过研究决定使用mysql(5.7版本)数据库的geometry类型字段来保存地理位置坐标,使用虚拟列(Virtual Generated Column)来保存geohash值,便于查询。
本文主要讲解扩展mybatis和通用mapper,使其支持geometry类型字段的新增、修改、查询因项目中需要用到地理位置信息的存储、查询、计算等,经过研究决定使用mysql(5.7版本)数据库的geometry类型字段来保存地理位置坐标,使用虚拟列(Virtual Generated Column)来保存geohash值,便于查询。
需要了解geometry如何使用及优势可参看:
mysql中geometry类型的简单使用
MySQL Geometry扩展在地理位置计算中的效率优势
本文主要讲解扩展mybatis和通用mapper,使其支持geometry类型字段的新增、修改、查询
首先创建一张表,作为本文的案例
CREATE TABLE `t_user` (
`id` varchar(45) NOT NULL,
`name` varchar(10) NOT NULL COMMENT \'姓名\',
`gis` geometry NOT NULL COMMENT \'空间位置信息\',
`geohash` varchar(20)GENERATED ALWAYS AS (st_geohash(`gis`,8)) VIRTUAL NOT NULL COMMENT \'geo哈希\',
PRIMARY KEY (`id`),
UNIQUE KEY `id` (`id`),
SPATIAL KEY `idx_gis` (`gis`),
KEY `idx_geohash` (`geohash`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COMMENT=\'用户\';
创建对应的实体类
@Table(name = "t_user")
public class User {
private String id;
private String name;
@Column
private GeoPoint gis;
@VirtualGenerated
private String geohash;
}
其中GeoPoint类型是我们自定义的类型,用来对应mysql的geometry类型
public class GeoPoint {
public GeoPoint(BigDecimal lng, BigDecimal lat) {
this.lng = lng;
this.lat = lat;
}
/* 经度 */
private BigDecimal lng;
/* 纬度 */
private BigDecimal lat;
}
@VirtualGenerated注解是我们自定义的注解,用来标识虚拟列字段,使insert、update时能够忽略该字段
使tk通用mapper的insert支持geometry类型tk通用mapper默认生成的insert语句xml是这样
<
insert>
INSERT INTO t_user
<
trim prefix="(" suffix=")" suffixOverrides=",">
<
if test="id != null">
id,<
/if>
<
if test="name != null">
name,<
/if>
<
if test="gis != null">
gis,<
/if>
<
/trim>
<
trim prefix="VALUES(" suffix=")" suffixOverrides=",">
<
if test="id != null">
#{id},<
/if>
<
if test="name != null">
#{name},<
/if>
<
if test="gis != null">
#{gis},<
/if>
<
/trim>
<
/insert>
【扩展mybatis和通用mapper,支持mysql的geometry类型字段】而我们希望生成的insert语句xml是这样
<
insert>
INSERT INTO t_user
<
trim prefix="(" suffix=")" suffixOverrides=",">
<
if test="id != null">
id,<
/if>
<
if test="name != null">
name,<
/if>
<
if test="gis != null">
gis,<
/if>
<
/trim>
<
trim prefix="VALUES(" suffix=")" suffixOverrides=",">
<
if test="id != null">
#{id},<
/if>
<
if test="name != null">
#{name},<
/if>
<
if test="gis != null">
geomfromtext(\'point(${gis.lng} ${gis.lat})\'),<
/if>
<
/trim>
<
/insert>
于是...开始我们的修改,查看通用mapper的源码得知,通用insert主要是通过BaseInsertMapper和BaseInsertProvider这两个类实现的,所以我们仿造着创建GeoBaseInsertMapper.java 和 GeoBaseInsertProvider.java,其中GeoBaseInsertProvider.java直接复制BaseInsertProvider来修改即可
GeoBaseInsertMapper.java如下:
@RegisterMapper
public interface GeoBaseInsertMapper<
T>
{
@InsertProvider(type = GeoBaseInsertProvider.class, method = "dynamicSQL")
int insert(T record);
@InsertProvider(type = GeoBaseInsertProvider.class, method = "dynamicSQL")
int insertSelective(T record);
}
最主要的是GeoBaseInsertProvider.java
将
public class GeoBaseInsertProvider extends MapperTemplate {public GeoBaseInsertProvider(Class<
?>
mapperClass, MapperHelper mapperHelper) {
super(mapperClass, mapperHelper);
}public String insert(MappedStatement ms) {
Class<
?>
entityClass = getEntityClass(ms);
StringBuilder sql = new StringBuilder();
//获取全部列
Set<
EntityColumn>
columnList = EntityHelper.getColumns(entityClass);
EntityColumn logicDeleteColumn = SqlHelper.getLogicDeleteColumn(entityClass);
processKey(sql, entityClass, ms, columnList);
sql.append(SqlHelper.insertIntoTable(entityClass, tableName(entityClass)));
sql.append("<
trim prefix=\\"(\\" suffix=\\")\\" suffixOverrides=\\",\\">
");
//当某个列有主键策略时,不需要考虑他的属性是否为空,因为如果为空,一定会根据主键策略给他生成一个值
for (EntityColumn column : columnList) {
if (!column.isInsertable()) {
continue;
}
//忽略虚拟列
if (column.getEntityField().isAnnotationPresent(VirtualGenerated.class)) {
continue;
}
sql.append(column.getColumn() + ",");
}
sql.append("<
/trim>
");
sql.append("<
trim prefix=\\"VALUES(\\" suffix=\\")\\" suffixOverrides=\\",\\">
");
for (EntityColumn column : columnList) {
if (!column.isInsertable()) {
continue;
}
//忽略虚拟列
if (column.getEntityField().isAnnotationPresent(VirtualGenerated.class)) {
continue;
}
if (logicDeleteColumn != null &
&
logicDeleteColumn == column) {
sql.append(SqlHelper.getLogicDeletedValue(column, false)).append(",");
continue;
}//优先使用传入的属性值,当原属性property!=null时,用原属性
//自增的情况下,如果默认有值,就会备份到property_cache中,所以这里需要先判断备份的值是否存在
if (column.isIdentity()) {
sql.append(SqlHelper.getIfCacheNotNull(column, column.getColumnHolder(null, "_cache", ",")));
} else {
//判断字段是GeoPoint类型时,调用getGeoColumnHolder方法来生成
if (column.getJavaType() == GeoPoint.class) {
//<
if test="property != null">
geomfromtext(\'point(108.9498710632 34.2588125935)\'),<
/if>
sql.append(SqlHelper.getIfNotNull(column, getGeoColumnHolder(column), isNotEmpty()));
} else {
//其他情况值仍然存在原property中
sql.append(SqlHelper.getIfNotNull(column, column.getColumnHolder(null, null, ","), isNotEmpty()));
}}
//当属性为null时,如果存在主键策略,会自动获取值,如果不存在,则使用null
if (column.isIdentity()) {
sql.append(SqlHelper.getIfCacheIsNull(column, column.getColumnHolder() + ","));
} else {
//判断字段是GeoPoint类型时,调用getGeoColumnHolder方法来生成
if (column.getJavaType() == GeoPoint.class) {
//<
if test="property == null">
geomfromtext(\'point(108.9498710632 34.2588125935)\'),<
/if>
sql.append(SqlHelper.getIfIsNull(column, getGeoColumnHolder(column), isNotEmpty()));
} else {
//当null的时候,如果不指定jdbcType,oracle可能会报异常,指定VARCHAR不影响其他
sql.append(SqlHelper.getIfIsNull(column, column.getColumnHolder(null, null, ","), isNotEmpty()));
}
}
}
sql.append("<
/trim>
");
return sql.toString();
}/*
* insert GEO字段占位符
*/
private String getGeoColumnHolder(EntityColumn column){
return String.format("geomfromtext(\'point(${%s.lng} ${%s.lat})\'),",column.getProperty(),column.getProperty());
}//忽略以下部分代码}
让你的mapper接口继承GeoBaseInsertMapper
@Repository
public interface UserMapper extends GeoBaseInsertMapper<
User>
{
}
如果你理解了通用insert的修改,update的修改也同样如此,相信难不倒你,这里就不再贴代码了。
使mybatis查询支持将geometry类型字段映射到GeoPoint类型mybatis通过定义typeHandler将数据类型映射为java类型,mybatis内置了多种常见的typeHandler,但没有支持geometry,好在mybatis提供了足够的扩展性,我们可以自定义typeHandler,这里还需要在pom.xml引入jts库来解析
<
dependency>
<
groupId>
com.vividsolutions<
/groupId>
<
artifactId>
jts<
/artifactId>
<
version>
${jts.version}<
/version>
<
/dependency>
接下来是自定义的MysqlGeoPointTypeHandler
/*
* mybatis查询结果集中 mysql的geometry类型映射到GeoPoint对象
*/
@MappedTypes(value = https://www.songbingjia.com/android/{GeoPoint.class})
public class MysqlGeoPointTypeHandler extends BaseTypeHandler<
GeoPoint>
{private WKBReader _wkbReader;
public MysqlGeoPointTypeHandler(int srid) {
GeometryFactory _geometryFactory = new GeometryFactory(new PrecisionModel(), srid);
_wkbReader = new WKBReader(_geometryFactory);
}@Override
public void setNonNullParameter(PreparedStatement ps, int i, GeoPoint parameter, JdbcType jdbcType) {
//因为GeoPoint对象里包含经度和纬度两个值,无法直接适配到一个参数,所以也不会使用到这个方法
}@Override
public GeoPoint getNullableResult(ResultSet rs, String columnName) throws SQLException {
return fromMysqlWkb(rs.getBytes(columnName));
}@Override
public GeoPoint getNullableResult(ResultSet rs, int columnIndex) throws SQLException {
return fromMysqlWkb(rs.getBytes(columnIndex));
}@Override
public GeoPoint getNullableResult(CallableStatement cs, int columnIndex) throws SQLException {
return fromMysqlWkb(cs.getBytes(columnIndex));
}/*
* bytes转GeoPoint对象
*/
private GeoPoint fromMysqlWkb(byte[] bytes) {
if (bytes == null) {
return null;
}
try {
byte[] geomBytes = ByteBuffer.allocate(bytes.length - 4).order(ByteOrder.LITTLE_ENDIAN)
.put(bytes, 4, bytes.length - 4).array();
Geometry geometry = _wkbReader.read(geomBytes);
Point point = (Point) geometry;
return new GeoPoint(new BigDecimal(String.valueOf(point.getX())), new BigDecimal(String.valueOf(point.getY())));
} catch (Exception e) {
}
return null;
}
}
然后我们需要将MysqlGeoPointTypeHandler添加到mybatis配置中,这样mybatis在遇到GeoPoint时就知道怎么映射了。
这里演示用java代码来配置mybatis,也可以在mybatis.xml文件中配置
@Configuration
@MapperScan(basePackages = {"com.carson.**.mapper"}, sqlSessionTemplateRef = "sqlSessionTemplate")
public class MybatisConfig {@Bean
public SqlSessionFactory sqlSessionFactory(DataSource dataSource) {
SqlSessionFactoryBean bean = new SqlSessionFactoryBean();
bean.setDataSource(dataSource);
bean.setVfs(SpringBootVFS.class);
//添加XML目录
ResourcePatternResolver resolver = new PathMatchingResourcePatternResolver();
try {
bean.setMapperLocations(resolver.getResources("classpath:mybatis/**/*Mapper.xml"));
bean.setTypeAliasesPackage("com.carson.pojo");
//添加MysqlGeoPointTypeHandler
bean.setTypeHandlers(new TypeHandler[]{new MysqlGeoPointTypeHandler()});
bean.getObject().getConfiguration().setMapUnderscoreToCamelCase(true);
return bean.getObject();
} catch (Exception e) {
e.printStackTrace();
throw new RuntimeException(e);
}
}
}
完成这些以后查询的结果集里包含geometry类型的字段,就能映射到GeoPoint了,从而可以获取经纬度
源码在哪里? talk is cheap,show me the code!如果你懒得看以上长篇大论,只想要开箱即用的代码,就在这里了,有帮助的话记得给个star哦!
https://github.com/tzjzcy/mybatis-mysql-geo-boot
https://gitee.com/tzjzcy/mybatis-mysql-geo-boot
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