如何从 Java-MySQL 中的表中获取单个结果?
mysqlmysqli database更新于 2023/11/5 18:44:00
首先我们创建一个表 −
mysql> create table DemoTable -> ( -> Id int, -> Name varchar(20) -> ); Query OK, 0 rows affected (1.37 sec)
使用 insert 命令在表中插入一些记录 −
mysql> insert into DemoTable values(101,'Chris'); Query OK, 1 row affected (0.54 sec) mysql> insert into DemoTable values(102,'David'); Query OK, 1 row affected (0.18 sec) mysql> insert into DemoTable values(103,'Mike'); Query OK, 1 row affected (0.12 sec)
使用 select 语句显示表中的所有记录 −
mysql> select * from DemoTable;
这将产生以下输出 −
+------+-------+ | Id | Name | +------+-------+ | 101 | Chris | | 102 | David | | 103 | Mike | +------+-------+ 3 rows in set (0.00 sec)
现在让我们看看 Java-MySQL 代码。这将仅从表顶部获取一条记录 −
示例
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.Statement;
import com.mysql.jdbc.ResultSetMetaData;
public class OneResultDemo {
public static void main(String[] args) {
Connection con = null;
PreparedStatement ps = null;
Statement st = null;
ResultSet rs = null;
try {
con = DriverManager.getConnection("jdbc:mysql://localhost:3306/web?useSSL=false", "root", "123456");
String query = "select *from DemoTable " + " limit 1";
st = con.createStatement();
rs = st.executeQuery(query);
while (rs.next()) {
System.out.println("Id=" + rs.getInt("Id"));
System.out.println("Name=" + rs.getString("Name"));
}
}
catch (Exception e) {
e.printStackTrace();
}
}
}
输出
这将产生以下输出 −
Id=101 Name=Chris
