如何固定列大小[重复]

Question

我的结果集有问题。我无法获得固定长度的列。

ResultSetMetaData rsmd = rs.getMetaData();
int cols = rsmd.getColumnCount();
for(int i=1; i<=cols; i++)
    System.out.print(rsmd.getColumnLabel(i)+"\t");
System.out.println("\n--------------------------------------------------------------");
while(rs.next())
{

    for(int i=1; i<=cols; i++)
        System.out.print(rs.getString(i)+"\t");

    System.out.println();
}

表格是这样的

http://www.bilder-upload.eu/show.php?file=bf21f6-1527061884.png“表”

列名与数据不完全一致。

Answer 1

只需使用带有格式的打印（调整到所需的长度）：

ResultSetMetaData rsmd = rs.getMetaData();
int cols = rsmd.getColumnCount();
//format begins after 20 characters.

String format = "%-20s";

for(int i=1; i<=cols; i++)
    System.out.printf(format, rsmd.getColumnLabel(i));
System.out.println("\n--------------------------------------------------------------");
while(rs.next())
{

    for(int i=1; i<=cols; i++)
        System.out.printf(format, rs.getString(i));

    System.out.println();
}

例如：

public class FixedColumn {

    public static void main(String[] args) {
        String[] test = {"13333","2qweqwe","3dddd"};
        String[] test2 = {"dsds4","6","6e"};
        String format = "%-20s";        
        for (String s : test) {
            System.out.printf(format, s);
        }
        System.out.println();
        for (String s : test2) {
            System.out.printf(format, s);
        }

    }

}

会返回：