while (rs.next()) { String name = rs.getString("name"); String email = rs.getString("email");"name"是谁的
时间: 2024-02-29 08:55:38 浏览: 23
根据这段代码,"name"是数据库表中的一个字段,通过rs.getString("name")可以获取当前行中该字段的值。在这个while循环中,通过遍历ResultSet对象rs中的所有行,依次获取每一行中"name"字段和"email"字段的值,并赋值给本地变量name和email。因此,这里的"name"应该指的是数据库表中的某个字段,而非Java类中的属性。
相关问题
while (rs.next()) { String no = rs.getString(1); String name = rs.getString(2); Object password1 = rs.getString(3); Object sex = rs.getString(4); double salary = rs.getDouble(5); System.out.println("no:" + no + "\tname:" + name + "\tpassword:" + password1 + "\tsex:" + sex + "\tsalary:" + salary); }逐行解释
这是一个 while 循环,用于逐行读取查询结果。具体的解释如下:
1. rs.next() 方法用于判断是否还有下一行结果,如果有则返回 true,否则返回 false。
2. 在 while 循环中,使用 rs.getString() 和 rs.getDouble() 方法获取每行数据的各个字段值。其中,rs.getString(1) 表示获取第一列的数据,rs.getString(2) 表示获取第二列的数据,以此类推。
3. 将每行数据的各个字段值存储在变量 no、name、password1、sex 和 salary 中。
4. 使用 System.out.println() 方法将每行数据的各个字段值打印到控制台上。在打印时,使用了字符串拼接符号 + 和制表符 \t,使输出的数据更加易读。
5. 循环执行,直到没有下一行数据为止。
总的来说,这段代码用于遍历查询结果集中的每一行数据,并将其打印到控制台上。在实际应用中,可以根据需要修改输出方式和输出内容。
public void vipcx() throws Exception{ System.out.println("请输入你要查询的会员名字:"); String name=""; Scanner sc=new Scanner(System.in); name=sc.next(); String sql="select * from vip where name=?"; PreparedStatement pstmt=conn.prepareStatement(sql); pstmt.setString(1,name); ResultSet rs=pstmt.executeQuery(); while(rs.next()) { System.out.println(""+rs.getInt("vip_id")+"+"+rs.getString("name")+"+rs.getInt("number")+""); } }哪错了
代码中存在语法错误,正确的代码如下:
```
public void vipcx() throws Exception {
System.out.println("请输入你要查询的会员名字:");
String name="";
Scanner sc=new Scanner(System.in);
name=sc.next();
String sql="select * from vip where name=?";
PreparedStatement pstmt=conn.prepareStatement(sql);
pstmt.setString(1,name);
ResultSet rs=pstmt.executeQuery();
while(rs.next()) {
System.out.println(""+rs.getInt("vip_id")+"+"+rs.getString("name")+"+"+rs.getInt("number")+"");
}
}
```
在 `System.out.println` 语句中,字符串拼接时,`rs.getInt("number")` 的后面缺少了一个引号。此外,建议在方法中加入异常处理机制,否则代码可能会出现不可控的异常。
相关推荐
![doc](https://img-home.csdnimg.cn/images/20210720083327.png)
![ppt](https://img-home.csdnimg.cn/images/20210720083527.png)
![docx](https://img-home.csdnimg.cn/images/20210720083331.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
检查一下语法问题: while(rs.next()){ String xh=rs.getString("xh"); String name=rs.getString("name"); String classname=rs.getString("classname"); int age=rs.getInt("age"); String address=rs.getString("address"); String phone=rs.getString("phone"); String city=rs.getString("city"); String notes=rs.getString("notes"); out.println(""+xh+" "+name+" "+classname+" "+age+" "+address+" "+phone+" "+city+" "+notes+" "); //输出结果 }
String name = new String(request.getParameter("ZY").getBytes("ISO-8859-1"), "UTF-8"); System.out.print(name); if (name == null || name.isEmpty()) { %> 请输入中药名称,点击返回重新输入 <% }else{ Connection conn = null; Statement stmt = null; ResultSet rs = null; try { conn = SQLConn.openDB(); stmt = conn.createStatement(); // 执行查询等操作 String sql = "select ZYName,YLName,YDY,YX,GX,ZhongYao.ZZ as ZZ from Yaolei,ZhongYao where Yaolei.YLID=ZhongYao.YLID"; PreparedStatement pstmt = conn.prepareStatement(sql); //pstmt.setString(1, "%" + name + "%"); rs = pstmt.executeQuery(); int count = 0; if(rs.next()){ while (rs.next()) { String ZYName = rs.getString("ZYName"); System.out.print(name); if (name.trim().equals(ZYName.trim())) { // if (name.trim().equals(A.trim())) { %>为什么name.trim().equals(ZYName.trim())不成立
<% //连接数据库 String driver = "com.mysql.jdbc.Driver"; String url = "jdbc:mysql://localhost:3306/votedb?serverTimezone=UTC&characterEncoding=UTF-8"; String username = "root"; String password = "123456"; Connection conn = null; Statement stmt = null; ResultSet rs = null; try { Class.forName(driver); conn = DriverManager.getConnection(url, username, password); stmt = conn.createStatement(); rs = stmt.executeQuery("SELECT * FROM vote"); while(rs.next()){ String title = rs.getString("title"); %> <input type="radio" name="option" value="<%=title%>"><%=title%>
<% } } catch (Exception e) { e.printStackTrace(); } finally { //关闭连接 try { if (rs != null) { rs.close(); } if (stmt != null) { stmt.close(); } if (conn != null) { conn.close(); } } catch (SQLException e) { e.printStackTrace(); } } %> 提交投票选中后数据库数据变化
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
String name = new String(request.getParameter("ZY").getBytes("ISO-8859-1"), "UTF-8"); System.out.print(name); if (name == null || name.isEmpty()) { %> 请输入中药名称,点击返回重新输入 <% }else{ Connection conn = null; Statement stmt = null; ResultSet rs = null; try { conn = SQLConn.openDB(); stmt = conn.createStatement(); // 执行查询等操作 String sql = "select ZYName,YLName,YDY,YX,GX,ZhongYao.ZZ as ZZ from Yaolei,ZhongYao where Yaolei.YLID=ZhongYao.YLID"; PreparedStatement pstmt = conn.prepareStatement(sql); //pstmt.setString(1, "%" + name + "%"); rs = pstmt.executeQuery(); int count = 0; if(rs.next()){ while (rs.next()) { String ZYName = rs.getString("ZYName"); System.out.print(name); if (name.trim().equals(ZYName.trim())) { // if (name.trim().equals(A.trim())) { %>为什么name.trim().equals(ZYName.trim())不成立
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)
<% //连接数据库 String driver = "com.mysql.jdbc.Driver"; String url = "jdbc:mysql://localhost:3306/votedb?serverTimezone=UTC&characterEncoding=UTF-8"; String username = "root"; String password = "123456"; Connection conn = null; Statement stmt = null; ResultSet rs = null; try { Class.forName(driver); conn = DriverManager.getConnection(url, username, password); stmt = conn.createStatement(); rs = stmt.executeQuery("SELECT * FROM vote"); while(rs.next()){ String title = rs.getString("title"); %> <input type="radio" name="option" value="<%=title%>"><%=title%>
<% } } catch (Exception e) { e.printStackTrace(); } finally { //关闭连接 try { if (rs != null) { rs.close(); } if (stmt != null) { stmt.close(); } if (conn != null) { conn.close(); } } catch (SQLException e) { e.printStackTrace(); } } %> 提交投票选中后数据库数据变化
![](https://csdnimg.cn/download_wenku/file_type_ask_c1.png)