JDBC各个类详解_ResultSet_基本使用
ResultSet:结果集对象,封装查询的结果
next():游标向下移动一行
getXxx(参数):获取数据
Xxx:代表数据类型 如:int getint(); String getString();
参数:
1.int:代表列的编号,从1开始 如:getString(1);
2.String :代码列名称 如:getDouble(" balance");
package CN.XueQiang.JDBC; import java.sql.*; /** *删除accont表中的数据; */ public class JDBCDemo5 { public static void main(String[] args) { Connection conn = null; Statement stat = null; ResultSet rs = null; try { //1.注册驱动 Class.forName("com.mysql.jdbc.Driver"); //2.获取数据库创建连接对象 conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/win", "root", "njzyb555"); //3.定义sql String sql = "select * from accont"; //4.获取执行sql对象 stat = conn.createStatement(); //5.执行sql rs = stat.executeQuery(sql); //6.处理结果 //6.1让游标向下移动一行 rs.next(); //6.2获取数据 int id = rs.getInt(1); String name = rs.getString("name"); double banlance = rs.getDouble(3); System.out.println(id + "---" + name + "---" + banlance); } catch (ClassNotFoundException e) { throw new RuntimeException(e); } catch (SQLException e) { throw new RuntimeException(e); }finally { //7.释放资源 if (rs !=null) { try { rs.close(); } catch (SQLException e) { throw new RuntimeException(e); } if (conn !=null) { try { conn.close(); } catch (SQLException e) { throw new RuntimeException(e); } } } } } }
输出结果
JDBC各个类详解_ResultSet_遍历结果集
注意:
使用步骤:
1. 游标向下移动一行
2. 判断是否有数据
3. 获取数据
//循环判断游标是否是最后一行末尾。 while(rs.next()){ //获取数据 //6.2 获取数据 int id = rs.getInt(1); String name = rs.getString("name"); double balance = rs.getDouble(3); System.out.println(id + "---" + name + "---" + balance); }
package CN.XueQiang.JDBC; import java.sql.*; /** * 执行DDL语句 */ public class JDBCDemo7 { public static void main(String[] args) { Connection conn = null; Statement stmt = null; ResultSet rs = null; try { //1. 注册驱动 Class.forName("com.mysql.jdbc.Driver"); //2.获取连接对象 conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/win", "root", "njzyb555"); //3.定义sql String sql = "select * from accont"; //4.获取执行sql对象 stmt = conn.createStatement(); //5.执行sql rs = stmt.executeQuery(sql); //6.处理结果 //循环判断游标是否是最后一行末尾。 while(rs.next()){ //获取数据 //6.2 获取数据 int id = rs.getInt(1); String name = rs.getString("name"); double balance = rs.getDouble(3); System.out.println(id + "---" + name + "---" + balance); } /* //6.1 让游标向下移动一行 if(rs.next()){ //判断是否有数据 //6.2 获取数据 int id = rs.getInt(1); String name = rs.getString("name"); double balance = rs.getDouble(3); System.out.println(id + "---" + name + "---" + balance); } //6.1 让游标向下移动一行 if(rs.next()){ //判断是否有数据 //6.2 获取数据 int id = rs.getInt(1); String name = rs.getString("name"); double balance = rs.getDouble(3); System.out.println(id + "---" + name + "---" + balance); } //6.1 让游标向下移动一行 if(rs.next()){ //判断是否有数据 //6.2 获取数据 int id = rs.getInt(1); String name = rs.getString("name"); double balance = rs.getDouble(3); System.out.println(id + "---" + name + "---" + balance); } //6.1 让游标向下移动一行 if(rs.next()){ //判断是否有数据 //6.2 获取数据 int id = rs.getInt(1); String name = rs.getString("name"); double balance = rs.getDouble(3); System.out.println(id + "---" + name + "---" + balance); }*/ /* //6.1 让游标向下移动一行 rs.next(); //6.2 获取数据 int id2 = rs.getInt(1); String name2 = rs.getString("name"); double balance2 = rs.getDouble(3); System.out.println(id2 + "---" + name2 + "---" + balance2); //6.1 让游标向下移动一行 rs.next(); //6.2 获取数据 int id3 = rs.getInt(1); String name3 = rs.getString("name"); double balance3 = rs.getDouble(3); System.out.println(id3 + "---" + name3 + "---" + balance3);*/ } catch (ClassNotFoundException e) { e.printStackTrace(); } catch (SQLException e) { e.printStackTrace(); } finally { //7.释放资源 if(rs != null){ try { rs.close(); } catch (SQLException e) { e.printStackTrace(); } } if(stmt != null){ try { stmt.close(); } catch (SQLException e) { e.printStackTrace(); } } if(conn != null){ try { conn.close(); } catch (SQLException e) { e.printStackTrace(); } } } } }
//循环判断游标是否是最后一行末尾。标签:JDBC,name,rs,ResultSet,---,获取数据,详解,id,String From: https://www.cnblogs.com/x3449/p/16818124.html
while(rs.next()){
//获取数据
//6.2 获取数据
int id = rs.getInt(1);
String name = rs.getString("name");
double balance = rs.getDouble(3);
System.out.println(id + "---" + name + "---" + balance);
}