如何格式化数据，使其以内联方式显示？

Question

该代码工作正常，并从数据库获取数据。看一看输出，你会看到问题吗？我如何格式化这些数据，以便cols可以很好地内联显示。我不想使用复杂的表或数据集输出我的结果。我只想在每个科尔之间加上“t”。

这里是输出：

  ID    FIRSTNAME   LASTNAME    USERNAME    AGE 
  2     Dave    Bill    DaveB   30  
  3     Jane    Mark    JaneM   37   
  4     Voo Gorge   VooG    50  




public class ex02 {
public static void main(String[] args) {
    String url = "jdbc:ucanaccess:Database11.accdb";

    Connection con;
    Statement stmt;
    String query = "Select * from user";

    try {
        Class.forName("net.ucanaccess.jdbc.UcanaccessDriver");
    } catch (java.lang.ClassNotFoundException e) {
        System.err.print("ClassNotFoundException: ");
        System.err.println(e.getMessage());
    }

    try {
        con = DriverManager.getConnection(url, "", "");
        stmt = con.createStatement();
       ResultSet rs = stmt.executeQuery(query);

        ResultSetMetaData rsmd = rs.getMetaData();
        int columns = rsmd.getColumnCount();
        for (int i = 1; i <= columns; i++) {
            System.out.print(rsmd.getColumnLabel(i) + "\t");
        }
        System.out.println();

        // Display columns data from database
        while (rs.next()) {
            for (int i = 1; i <= columns; i++) {
                System.out.print(rs.getString(i) + "\t");
            }
            System.out.println();
        }

        stmt.close();
        con.close();
    } catch (SQLException ex) {
        System.err.println("SQLException: " + ex.getMessage());
    }
}

}

Answer 1

您可以从ApacheCommons查看StringUtils.rightPad() (或者自己编写一些类似的代码)。将rightPad与将列值限制为最大长度相结合，会给您提供一个格式良好的输出。

Answer 2

可以用固定长度对齐列进行左或右对齐。这里有一个例子，将它们都设置为相同的理由。

public static void main(String[] args) throws Exception {
    List<String[]> dataTable = new ArrayList() {{
        add(new String[] {"ID", "FIRSTNAME", "LASTNAME", "USERNAME", "AGE"}); 
        add(new String[] {"2", "Dave", "Bill", "DaveB", "30"});  
        add(new String[] {"3", "Jane", "Mark", "JaneM", "37"});   
        add(new String[] {"4", "Voo", "Gorge", "VooG", "50"});  
    }};

    // Left justified 15 character width
    System.out.println("Left Justified");
    for (String[] row : dataTable) {
        for (String col : row) {
            System.out.printf("%-15s", col);
        }
        System.out.println();
    }
    System.out.println();

    // Right justified 15 character width
    System.out.println("Right Justified");
    for (String[] row : dataTable) {
        for (String col : row) {
            System.out.printf("%15s", col);
        }
        System.out.println();
    }
}

结果：

Left Justified
ID             FIRSTNAME      LASTNAME       USERNAME       AGE            
2              Dave           Bill           DaveB          30             
3              Jane           Mark           JaneM          37             
4              Voo            Gorge          VooG           50             

Right Justified
             ID      FIRSTNAME       LASTNAME       USERNAME            AGE
              2           Dave           Bill          DaveB             30
              3           Jane           Mark          JaneM             37
              4            Voo          Gorge           VooG             50