Java printf方法创建标题

我想知道如何使用printf方法为我的列创建标题：

 Statement stmt = conn.createStatement();
    ResultSet rset = stmt.executeQuery("select country_id,country_name,region_id,last_name from countries");

    while (rset.next())
        System.out.printf("%-5s %-25s %5s \n", rset.getString("country_id"),rset.getString("country_name"),rset.getString("region_id"));

    stmt.close();
    conn.close();

输出是这样的，我希望在每列上方都有一个标题！我该怎么做

AR    Argentina                     2 
AU    Australia                     3 
BE    Belgium                       1 
BR    Brazil                        2 
CA    Canada                        2 
CH    Switzerland                   1 
CN    China                         3 
DE    Germany                       1 
DK    Denmark                       1 
EG    Egypt                         4 
FR    France                        1 
IL    Israel                        4 
IN    India                         3 
IT    Italy                         1 
JP    Japan                         3 
KW    Kuwait                        4 
ML    Malaysia                      3 
MX    Mexico                        2 
NG    Nigeria                       4 
NL    Netherlands                   1 
SG    Singapore                     3 
UK    United Kingdom                1 
US    United States of America      2 
ZM    Zambia                        4 
ZW    Zimbabwe                      4 

---

在循环之前把它打印出来

Statement stmt = conn.createStatement();
ResultSet rset = stmt.executeQuery("select country_id,country_name,region_id,last_name from countries");

System.out.printf("%-5s %-25s %5s \n", "country_id","country_name","region_id");
while (rset.next())

    System.out.printf("%-5s %-25s %5s \n", rset.getString("country_id"),rset.getString("country_name"),rset.getString("region_id"));
stmt.close();
conn.close();

---

您只需要另一个

System.out.println（）

语句，如下所示：

Statement stmt = conn.createStatement();
ResultSet rset = stmt.executeQuery("select country_id,country_name,region_id,last_name from countries");
System.out.printf("%-5s %-25s %5s \n", "Country Id", "Name", "Region Id");
while (rset.next())

System.out.printf("%-5s %-25s %5s \n", rset.getString("country_id"),rset.getString("country_name"),rset.getString("region_id"));
stmt.close();
conn.close();

---

如果要为所有列整体查找常规标题，则应按如下方式打印：

System.out.println("Country_ID Country_Name Region_ID");

将此添加到

while

循环之前

或者，如果要在每行列组之前打印相同的标题，则应尝试以下操作：

while (rset.next())
    {

        System.out.println("Country_ID Country_Name Region_ID");
        System.out.printf("%-5s %-25s %5s \n", rset.getString("country_id"),rset.getString("country_name"),rset.getString("region_id"));
    }

只需添加以下内容：

Statement stmt = conn.createStatement();
    ResultSet rset = stmt.executeQuery("select country_id,country_name,region_id,last_name from countries");
    System.out.printf("%-5s %-25s %5s \n", "Country Id", "Name", "Region Id");
    while (rset.next())

    System.out.printf("%-5s %-25s %5s \n", rset.getString("country_id"),rset.getString("country_name"),rset.getString("region_id"));
    stmt.close();
    conn.close();

您可以使用：

Statement stmt = conn.createStatement();

ResultSet rset = stmt.executeQuery("select country_id,country_name,region_id,last_name from countries");

System.out.printf("%-5s %-25s %5s \n", "country_id","country_name","region_id");

System.out.printf("%-5s %-25s %5s \n", "----------","------------","---------");
while (rset.next())
System.out.printf("%-5s %-25s %5s \n", rset.getString("country_id"),rset.getString("country_name"),rset.getString("region_id"));
stmt.close();
conn.close();

---

每一列？或者您希望在所有列的上方都有一个标题？其中AR AU BE BR CA etc是一列！阿根廷、比利时、巴西等是另一个。。我想在这些列上加一个标题！不，我需要每个专栏！所以我想要3个头球@用户2985600如果这是您想要的，请将其标记为答案。