按名称从 ResultSet 中获取值

Question

如何通过属性名称从 ResultSet 中获取值？

DB-Table（表）：

name:TEXT | age:INT | gender:INT

SQL 查询：

SELECT * FROM table WHERE name='john'

输出在java.sql.ResultSet

如何按列名（姓名、年龄、性别）获取变量？

Answer 1

您可以像这样迭代这些值：

Statement stmt = null;
    String query = "SELECT * FROM table WHERE name='john'";
    try {
        stmt = con.createStatement();
        ResultSet rs = stmt.executeQuery(query);
        while (rs.next()) {
            String name= rs.getString("name");
            int age= rs.getInt("age");
            int gender = rs.getInt("gender");
        }
    } catch (Exception e ) {
        e.printStackTrace();
    } finally {
        if (stmt != null) { stmt.close(); }
    }

Answer 2

使用ResultSetMetaData:

ResultSetMetaData metaData = resultSet.getMetaData();

例如：

...
 ResultSet rs = stmt.executeQuery(query);
   while (rs.next()) {
         int count = metaData.getColumnCount();
         for (int i = 1; i <= count; i++)
         {
           String columnName = metaData.getColumnName(i);
           int type = metaData.getColumnType(i);
           if (type == Types.VARCHAR || type == Types.CHAR) {
               out.print(rs.getString(columnName));
               String name= rs.getString(columnName);
           }
           if (type==Types.INTEGER){
               out.print(rs.getInt(columnName));
               int age= rs.getInt(columnName);
            }
           // ....
           // save columnName and name
         }
    }
 }

...