geoserver源码学习与扩展——CSV转shapefile文件

基于geotools实现csv转换为shapefile文件。

1、读取CSV文件，将其装入FeatureCollection；

2、利用ShapefileDumper类将FeatureCollection转存到硬盘；

 　　　/*
　　　　* transform CSV to FeatureCollection
　　　　*/
 1     public void processCSVFile(File csvFile){

         ListFeatureCollection collection;
         try{
             typeName = csvFile.getName().replace(".", "_");
             typeName = replaceBlank(typeName);
             BufferedReader reader = new BufferedReader(new FileReader(csvFile));
             try{
                 /* First line of the data file is the header */
                 String line = reader.readLine();
                 System.out.println("Header: " + line);

                 /*
                  * We use the DataUtilities class to create a FeatureType that will describe the data in our
                  * shapefile.
                  *
                  * See also the createFeatureType method below for another, more flexible approach.
                  */
                 String[] strArray  = line.split("\\,");
                 int latDex = -1;
                 int longDex = -1;
                 List<String> typeSpec = new ArrayList<String>();
                 typeSpec.add("the_geom:Point:srid="+ SRID); // <- the geometry attribute: Point type
                 for(int i = 0; i < strArray.length; i ++){
                     if(strArray[i].contains("Lat")){
                         latDex = i;
                     }
                     else if(strArray[i].contains("Long")){
                         longDex = i;
                     }
                     else{
                         typeSpec.add(strArray[i] + ":String");    //all String type
                     }
                 }
                 if(CreateCluster)
                     typeSpec.add("cluster:String");    //add cluster field
                 String typeSpecs = String.join(",", typeSpec);
                 final SimpleFeatureType TYPE = DataUtilities.createType(typeName,
                                 typeSpecs // other attribute
                         );
                 /*
                  * GeometryFactory will be used to create the geometry attribute of each feature (a Point
                  * object for the location)
                  */
                 GeometryFactory geometryFactory = JTSFactoryFinder.getGeometryFactory(null);
                 SimpleFeatureBuilder featureBuilder = new SimpleFeatureBuilder(TYPE);
                 /*
                  * We create a FeatureCollection into which we will put each Feature created from a record
                  * in the input csv data file
                  */
                 collection = new ListFeatureCollection(TYPE);

                 for (line = reader.readLine(); line != null; line = reader.readLine()) {
                     if (line.trim().length() > 0) { // skip blank lines
                         String tokens[] = line.split("\\,");
                         double latitude = Double.parseDouble(tokens[latDex]);
                         double longitude = Double.parseDouble(tokens[longDex]);

                         /* Longitude (= x coord) first ! */
                         Point point = geometryFactory.createPoint(new Coordinate(longitude, latitude));

                         featureBuilder.add(point);;
                         for(int i = 0; i < tokens.length; i ++){
                             if(latDex != i && longDex != i){
                                 String strVal = tokens[i].trim();
                                 featureBuilder.add(strVal);
                             }
                         }

                         if(CreateCluster)
                             featureBuilder.add("");    //add cluster field value
                         SimpleFeature feature = featureBuilder.buildFeature(null);
                         collection.add(feature);
                     }
                 }
             } finally {
                 reader.close();
             }
             writeShapeFile(collection);

         }
         catch(Exception ex){
             System.out.println(ex.getMessage());
         }
     }

CSV文件并不包含各字段的类型说明，将经纬度字段转换为Geometry，其他字段都为String类型；

另外，DataUtilities.createType方法创建要素方案时，将所有的String类型的字段长度都设为了java环境下的默认长度254，若字段太多或要素太多会导致shapefile中的dbf文件过大，可参考DataUtilities类，编写自定义类将String类型长度设为自定义长度；

     /*
      * FeatureCollection to shapefile
     */
     private void writeShapeFile(SimpleFeatureCollection collection){
         final File baseDir = resourceLoader.getBaseDirectory();
         File shpDir = new File(baseDir.getAbsolutePath() + "/Data/upload");
         if(!shpDir.exists()){
             shpDir.mkdirs();
         }
         if(!shpDir.exists())
             return;

         ShapefileDumper dumper = new ShapefileDumper(shpDir);
         dumper.setMaxDbfSize(maxDbfSize);
         dumper.setMaxShpSize(maxShpSize);
         dumper.setCharset(Charset.forName(charSet));

         // target charset

         try {
             // if an empty result out of feature type with unknown geometry is created, the
             // zip file will be empty and the zip output stream will break
             boolean shapefileCreated = false;
             shapefileCreated |= dumper.dump(collection);

             // take care of the case the output is completely empty
             if(!shapefileCreated) {
                 createEmptyWarning(shpDir);
             }

         }
         catch(Exception ex){
             System.out.println(ex.getMessage());
         }

     }

     private void createEmptyWarning(File tempDir) throws IOException {
         PrintWriter pw = null;
         try {
             pw = new PrintWriter(new File(tempDir, "README.TXT"));
             pw.print("The CSV Upload result is empty, and the geometric type of the features is unknwon:"
                     + "an empty point shapefile has been created");
         } finally {
             pw.close();
         }
     }