在入庫和查詢中需要自動的讓geography的型別和實體類中的型別對映。

實體類中接收引數是String型別（geoJson）

PostGis中的geography型別是十六進位制的擴充套件WKB型別（EWKB），

雖然Postgis資料庫中提供類型別轉換函式，能轉換各種型別：postgis常用命令_yaoct的部落格-CSDN部落格

但是基於mybatis框架查詢時，就需要用java程式碼來轉換。初步方案時mybatis中的型別轉換器。

先引入java處理GIS的庫，這裡用的是Geotools庫。

1、geotools的maven引入

<properties>
	<
 
geotools.version>20.0</geotools.version>
  </properties>

  <dependencies>
	<!-- geotools相關jar包 -->
    <dependency>
      <groupId>org.geotools</groupId>
      <artifactId>gt-geojson</artifactId>
      <version>${geotools.version}</version>
 

    </dependency>
    <dependency>
      <groupId>org.geotools</groupId>
      <artifactId>gt-swing</artifactId>
      <version>${geotools.version}</version>
    </dependency>
    <dependency>
      <groupId>org.geotools</groupId>
      <
 
artifactId>gt-jdbc</artifactId>
      <version>${geotools.version}</version>
    </dependency>
    <dependency>
      <groupId>org.geotools.jdbc</groupId>
      <artifactId>gt-jdbc-postgis</artifactId>
      <version>${geotools.version}</version>
    </dependency>
    <dependency>
      <groupId>org.geotools</groupId>
      <artifactId>gt-epsg-hsql</artifactId>
      <version>${geotools.version}</version>
    </dependency>
    <dependency>
      <groupId>org.geotools</groupId>
      <artifactId>gt-shapefile</artifactId>
      <version>${geotools.version}</version>
    </dependency>
    <dependency>
      <groupId>org.geotools</groupId>
      <artifactId>gt-main</artifactId>
      <version>${geotools.version}</version>
    </dependency>
    <dependency>
      <groupId>org.geotools</groupId>
      <artifactId>gt-api</artifactId>
      <version>${geotools.version}</version>
    </dependency>
    <dependency>
      <groupId>org.geotools</groupId>
      <artifactId>gt-opengis</artifactId>
      <version>${geotools.version}</version>
    </dependency>
    <dependency>
      <groupId>org.geotools</groupId>
      <artifactId>gt-data</artifactId>
      <version>${geotools.version}</version>
    </dependency>
    <dependency>
      <groupId>org.geotools</groupId>
      <artifactId>gt-referencing</artifactId>
      <version>${geotools.version}</version>
    </dependency>
	<dependency>
      <groupId>net.postgis</groupId>
      <artifactId>postgis-jdbc</artifactId>
      <version>2.5.0</version>
    </dependency>
  </dependencies>

  <repositories>
    <repository>
      <id>osgeo</id>
      <name>OSGeo Release Repository</name>
      <url>https://repo.osgeo.org/repository/release/</url>
      <snapshots><enabled>false</enabled></snapshots>
      <releases><enabled>true</enabled></releases>
    </repository>
    <repository>
      <id>osgeo-snapshot</id>
      <name>OSGeo Snapshot Repository</name>
      <url>https://repo.osgeo.org/repository/snapshot/</url>
      <snapshots><enabled>true</enabled></snapshots>
      <releases><enabled>false</enabled></releases>
    </repository>
  </repositories>

2、Geotools工具類轉換WKB和Geojson

WKBReader reader = new WKBReader( );
Geometry geometry = reader.read(WKBReader.hexToBytes("0101000020E61000002C39382229FD5D4085716007088C3E40"));
// 設定保留6位小數，否則GeometryJSON預設保留4位小數
GeometryJSON geometryJson = new GeometryJSON(7);
String s = geometryJson.toString(geometry);
System.out.println(s);

//{"type":"Point","coordinates":[119.9556356,30.5469975]}
//EWKB->轉geojson丟失資訊
Geometry read = geometryJson.read("{\"type\":\"Point\",\"coordinates\":[119.9556356,30.5469975]}");
System.out.println(read.toString());
WKBWriter wkbWriter = new WKBWriter();
byte[] write = wkbWriter.write(geometry);
String s1 = WKBWriter.toHex(write);
System.out.println(s1);