PostGIS之Java入門

相關的功能也可以使用jts.jar包實現

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

import org.junit.Before;
import org.junit.Test;
import org.postgresql.geometric.PGcircle;
import org.postgresql.geometric.PGpoint;

public class GeometricTest {

	private Connection conn;

	@Before
	public void init() throws Exception {
		Class.forName("org.postgresql.Driver");
		String url = "jdbc:postgresql://localhost:5432/postgis";
		conn = DriverManager.getConnection(url, "username", "password");
		Statement stmt = conn.createStatement();
		stmt.execute("CREATE TEMP TABLE geomtest(mycirc circle)");
		stmt.close();
	}
	
	public void destroy() throws SQLException {
		if (conn != null) {
			conn.close();
		}
	}

	@Test
	public void insertCircle() throws SQLException {

		PGpoint center = new PGpoint(1, 2.5);
		// PGpolygon polygon = new PGpolygon(points);
		double radius = 4;
		PGcircle circle = new PGcircle(center, radius);

		PreparedStatement ps = conn.prepareStatement("INSERT INTO geomtest(mycirc) VALUES (?)");
		ps.setObject(1, circle);
		ps.executeUpdate();
		ps.close();
	}

	@Test
	public void retrieveCircle() throws SQLException {
		Statement stmt = conn.createStatement();
		ResultSet rs = stmt.executeQuery("SELECT mycirc, area(mycirc) FROM geomtest");
		rs.next();
		PGcircle circle = (PGcircle) rs.getObject(1);
		double area = rs.getDouble(2);
		// PG

		PGpoint center = circle.center;
		double radius = circle.radius;

		System.out.println("Center (X, Y) = (" + center.x + ", " + center.y + ")");
		System.out.println("Radius = " + radius);
		System.out.println("Area = " + area);
	}

	@Test
	public void getWKTFromGEOM() throws SQLException {
		Statement stmt = conn.createStatement();
		ResultSet rs = stmt.executeQuery("SELECT ST_AsText(geom) FROM sheng where name = '新疆維吾爾自治區'");
		rs.next();
		String wkt = rs.getString(1);
		System.out.println(wkt);
	}

	@Test
	public void getWKBFromGEOM() throws SQLException {
		Statement stmt = conn.createStatement();
		ResultSet rs = stmt.executeQuery("SELECT ST_AsBinary(geom) FROM sheng");
		rs.next();
		String wkt = rs.getString(1);
		System.out.println("wkt = " + wkt);
	}

	@Test
	public void getEWKTFromGEOM() throws SQLException {
		Statement stmt = conn.createStatement();
		ResultSet rs = stmt.executeQuery("SELECT ST_AsEWKT(geom) FROM sheng");
		rs.next();
		String wkt = rs.getString(1);
		System.out.println("wkt = " + wkt);
	}
	
	@Test
	public void getBufferFromGEOM() throws SQLException {
		Statement stmt = conn.createStatement();
		ResultSet rs = stmt.executeQuery("SELECT ST_AsEWKT(ST_Buffer(geom, 0.2)), ST_AsEWKT(geom) FROM sheng where id = 1");
		rs.next();
		String wkt = rs.getString(1);
		String wkt2 = rs.getString(2);
		//System.out.println("tt " + wkt.substring(0, 100));
		//System.out.println("tt " + wkt2.substring(0, 100));
	}
	
	/**
	 * 需要在postGis中模擬一個dual表（注意指明空間字段）
	 */
	@Test
	public void getBufferFromWKT() throws SQLException {
		// 新疆維吾爾自治區
		String wkt = PropertiesUtility.getInstance().findFileValue("system.properties", "wkt");
		long startTime = new java.util.Date().getTime();
		System.out.println(startTime);
		String sql = "SELECT ST_AsText(ST_Buffer(st_geomfromtext('" + wkt + "'), 0.2)) FROM dual";
		Statement stmt = conn.createStatement();
		ResultSet rs = stmt.executeQuery(sql);
		rs.next();

		long endTime = new java.util.Date().getTime();
		System.out.println(endTime);
		System.out.println("緩衝時間：" + (endTime - startTime));
		System.out.println("座標點數：" + wkt.split(",").length);
	}

	/**
	 * 根據指定的緩衝距離進行緩衝，以米爲單位
	 */
	@Test
	public void getBufferFromWKT2() throws SQLException {
		// 新疆維吾爾自治區  wkt=MULTIPOLYGON(((79.036744 34.3364.............
		String wkt = PropertiesUtility.getInstance().findFileValue("system.properties", "wkt");
		long startTime = new java.util.Date().getTime();
		System.out.println(startTime);
		// 緩衝距離爲10.8KM
		String sql = "SELECT ST_AsText(st_transform(st_setsrid(ST_Buffer(st_transform(st_setsrid(st_geomfromtext('" + wkt
				+ "'), 4326), 2333), 10800), 2333), 4326)) FROM dual";
		Statement stmt = conn.createStatement();
		ResultSet rs = stmt.executeQuery(sql);
		rs.next();
		String resultWKT = rs.getString(1);

		System.out.println(resultWKT);

		long endTime = new java.util.Date().getTime();
		System.out.println(endTime);
		System.out.println("緩衝時間：" + (endTime - startTime));
		System.out.println("座標點數：" + wkt.split(",").length);
	}

	// 判斷點是否在多邊形內
	@Test
	public void getWithin() throws SQLException {
		Statement stmt = conn.createStatement();
		String sql = "SELECT name FROM sheng where ST_Within(ST_MakePoint(116.561, 40.276), geom)";
		ResultSet rs = stmt.executeQuery(sql);
		while (rs.next()) {
			String wkt = rs.getString(1);
			System.out.println(wkt);
		}
	}
}