嘗試使用Java和MetaModel API查詢.CSV文件

Question

我正在嘗試使用Java和MetaModel API查詢.CSV文件，但未成功。這個API很容易使用.XLS文件，但使用.CSV，我很難過，因爲SQL查詢沒有表名。任何人都可以提供任何暗示或見解如何做到這一點？

public static Object[][] getCsvData(File csvFile) 
{ 
    CsvConfiguration conf = new CsvConfiguration(1, true, false); 
    DataContext ctx = DataContextFactory.createCsvDataContext(csvFile, conf); 

// CsvDataSet dataSet = csvContext.query(). 
//  .selectAll() 
//  .where("run").eq("Y") 
//  .execute(); 
// List<Row> rows = dataSet.toRows(); 

如果您想嘗試一下我的代碼，看到我GitHub project在這裏，這是正在進行概念證明（有工作Excel的例子）。

Answer 1

你可以像這樣爲CSV

public static Object[][] getCsvData(File csvFile) { 
     CsvConfiguration conf = new CsvConfiguration(1); 
     DataContext csvContext = DataContextFactory.createCsvDataContext(
       csvFile, conf); 
     Schema schema = csvContext.getDefaultSchema(); 
     Table[] tables = schema.getTables(); 
     Table table = tables[0]; 
     DataSet dataSet = csvContext.query().from(table).selectAll().where("run").eq("Y").execute(); 
     List<Row> rows = dataSet.toRows(); 
     Object[][] myArray = new Object[rows.size()][2]; 
     int i = 0; 
     SelectItem[] cols = rows.get(0).getSelectItems(); 
     for (Row r : rows) { 
      Object[] data = r.getValues(); 
      for (int j = 0; j < cols.length; j++) { 
       if (data[j] == null) 
        data[j] = ""; // force empty string where there are NULL 
            // values 
      } 
      myArray[i][0] = cols; 
      myArray[i][1] = data; 
      i++; 
     } 
     logger.info("Row count: " + rows.size()); 
     logger.info("Column names: " + Arrays.toString(cols)); 
     return myArray; 
    } 

我想它對於XmlDataProvider你可以像這樣

@Test 
    public void testXML() { 

     XmlSaxTableDef employeeTableDef = new XmlSaxTableDef(
       "/root/organization/employees/employee", new String[] { 
         "/root/organization/employees/employee/name", 
         "/root/organization/employees/employee/gender", 
         "index(/root/organization)"}); 

     XmlSaxTableDef organizationTableDef = new XmlSaxTableDef(
       "/root/organization", new String[] { 
         "/root/organization/name", 
         "/root/organization@type" }); 

     DataContext dc = new XmlSaxDataContext(xmlFile, employeeTableDef, 
       organizationTableDef); 

     Table employeeTable = dc.getTableByQualifiedLabel("/employee"); 
     Column fk = employeeTable.getColumnByName("index(/root/organization)"); 
     Column empName = employeeTable.getColumnByName("/name"); 

     Table organizationTable = dc.getTableByQualifiedLabel("/organization"); 
     Column orgId = organizationTable.getColumnByName("row_id"); 
     Column orgName = organizationTable.getColumnByName("/name"); 
     Query q = dc.query().from(employeeTable) 
       .innerJoin(organizationTable).on(fk, orgId) 
       .select(empName).as("employeename") 
       .select(orgName).as("companyname").toQuery(); 
     DataSet ds = dc.executeQuery(q); 

     List<Row> rows = ds.toRows(); 
     for (Row r : rows) { 
      System.out.println(Arrays.deepToString(r.getValues())); 
     } 

    } 

讓我知道，如果你面對任何問題:)