java - JDBC如何查询某个表中的全部数据

Question

有一个数据表，但是不知道行数和列数，用java如何把这个表中的全部数据提取出来。用双重for循环遍历吗。

Answer 1

Isn’t it enough to directly use the sql statement select * from tableName... Use the next() method to iterate...

Answer 2

The method is mentioned above. The next() method is to get one row of data at a time. If not, it returns false, so you can get all the data with while(rs.next())

Answer 3

select * from table；while（res.next()）来迭代;

Answer 4

1. Query all the data in the table: SELECT * FROM table；
2、使用JDBC提供的java.sql.ResultSetMetaDataThe class can obtain the number of columns contained in the query result and the name of each column (ColumnLabel) in the query result set;
As mentioned above, use next() to traverse the result set .

Answer 5

SELECT * The data queried from the database is divided into rows.
while(rs.next()) can be seen as determining whether there is a next line.
java.sql.ResultSet provides a method to get columns, rs.getString(1). (Columns are numbered from left to right and start at column 1)