需求：從一個(gè)nc文件中取出我想要的變量，導(dǎo)出到另外一個(gè)nc文件。

下面是基本代碼：

@GetMapping("/export") public String varExport(@ModelAttribute FileSaveVars params ) throws IOException, InvalidRangeException { // 1° 設(shè)置原始文件路徑+轉(zhuǎn)存文件路徑String filePath = "/Users/caowei/workspace/jszone/大氣系統(tǒng)/ncdemo/src/main/resources/static/MERRA2_400.tavg1_2d_flx_Nx.20180101.SUB.nc";String savePath = "/Users/caowei/workspace/test.nc"; // 2° 讀取文件NetcdfFile ncFile = null;ncFile = NetcdfFile.open(filePath, null); // 3° 獲取需要轉(zhuǎn)存的變量Variable latVar = ncFile.findVariable("lat"); // 4° 讀取變量的一些信息 // 4°-1 長(zhǎng)度int latitudeCount = (int) latVar.getSize(); // 4°-2 讀取變量數(shù)組數(shù)據(jù)ArrayDouble.D1 latArray = (ArrayDouble.D1) latVar.read(); // 5° 構(gòu)造輸出保存文件NetcdfFileWriter ncWrite = NetcdfFileWriter.createNew(NetcdfFileWriter.Version.netcdf4, savePath); // 6° 設(shè)置文件的一些參數(shù) // 6°-1緯度Dimension latitudeDimension = ncWrite.addDimension(null, "latitude", (int) latArray.getSize()); // 6°-2變量Variable latitudeVar = ncWrite.addVariable(null, "latitude", DataType.DOUBLE, "latitude"); // 6°-3設(shè)置屬性latitudeVar.addAttribute(new Attribute("standard_name", "latitude"));latitudeVar.addAttribute(new Attribute("long_name", "latitude"));latitudeVar.addAttribute(new Attribute("units", "degrees_north"));latitudeVar.addAttribute(new Attribute("axis", "Y")); // 7°創(chuàng)建ncWrite.create(); // 8° 構(gòu)造數(shù)據(jù)ArrayDouble.D1 latitudeData = latArray; // 9°將數(shù)據(jù)寫入ncWrite.write(latitudeVar, latitudeData); // 10°關(guān)閉保存ncWrite.close();return "OK"; }

下面是抽出一個(gè)變量進(jìn)行導(dǎo)出

@GetMapping("/export")public String varExport(@ModelAttribute FileSaveVars params ) throws IOException, InvalidRangeException { // 1° 設(shè)置原始文件路徑+轉(zhuǎn)存文件路徑String filePath = "/Users/caowei/workspace/jszone/大氣系統(tǒng)/ncdemo/src/main/resources/static/MERRA2_400.tavg1_2d_flx_Nx.20180101.SUB.nc";String savePath = "/Users/caowei/workspace/test.nc"; // 2° 讀取文件NetcdfFile ncFile = null;ncFile = NetcdfFile.open(filePath, null); // 3° 設(shè)置需要轉(zhuǎn)存的變量String varName = "lon"; // 4° 獲取需要轉(zhuǎn)存的變量對(duì)象Variable varObject = ncFile.findVariable(varName); // 5° 讀取變量的一些信息 // 5°-1 長(zhǎng)度int varCount = (int) varObject.getSize(); // 6° 構(gòu)造輸出保存文件NetcdfFileWriter ncWrite = NetcdfFileWriter.createNew(NetcdfFileWriter.Version.netcdf4, savePath); // 7° 設(shè)置文件的一些參數(shù) // 7°-1緯度Dimension varDimension = ncWrite.addDimension(null, varObject.getName().toString(), varCount); // 7°-2變量Variable varVar = ncWrite.addVariable(null, varObject.getName().toString(), varObject.getDataType(), varDimension.getName()); // 7°-3設(shè)置屬性List<Attribute> AttrList = varObject.getAttributes();for (Attribute att : AttrList) {varVar.addAttribute(att);} // 8°創(chuàng)建ncWrite.create(); // 9°將數(shù)據(jù)寫入ncWrite.write(varVar, varObject.read()); // 10°關(guān)閉保存ncWrite.close();return "OK"; }

下面再次進(jìn)行升級(jí)，可以直接導(dǎo)出單個(gè)三緯變量

@GetMapping("/export") public String varExport(@ModelAttribute FileSaveVars params ) throws IOException, InvalidRangeException { // 1° 設(shè)置原始文件路徑+轉(zhuǎn)存文件路徑String filePath = "/Users/caowei/workspace/jszone/大氣系統(tǒng)/ncdemo/src/main/resources/static/MERRA2_400.tavg1_2d_flx_Nx.20180101.SUB.nc";String savePath = "/Users/caowei/workspace/test.nc"; // 2° 讀取文件NetcdfFile ncFile = NetcdfFile.open(filePath, null); // 3° 設(shè)置需要轉(zhuǎn)存的變量String varName = "QLML"; // 4° 獲取需要轉(zhuǎn)存的變量對(duì)象Variable varObject = ncFile.findVariable(varName); // 5° 構(gòu)造輸出保存文件NetcdfFileWriter ncWrite = NetcdfFileWriter.createNew(NetcdfFileWriter.Version.netcdf4, savePath); // 6° 設(shè)置文件的一些參數(shù) // 7°-1緯度for(Dimension dimension : varObject.getDimensions()){ncWrite.addDimension(null, dimension.getShortName(), dimension.getLength());} // 6°-2變量Variable varVar = ncWrite.addVariable(null, varObject.getShortName(), varObject.getDataType(), varObject.getDimensionsString()); // 6°-3設(shè)置屬性List<Attribute> AttrList = varObject.getAttributes();for (Attribute att : AttrList) {varVar.addAttribute(att);} // 7°創(chuàng)建ncWrite.create(); // 8°將數(shù)據(jù)寫入ncWrite.write(varVar, varObject.read()); // 9°關(guān)閉保存ncWrite.close();return "OK"; }

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