### JSP 连接并查询数据库的解决方案
以下是针对不同类型的数据库提供的一系列 JSP 示例代码，用于展示如何通过 JDBC 驱动程序连接到数据库以及执行简单的查询。
#### Oracle 数据库连接与查询
以下是一个完整的示例，展示了如何使用 JSP 页面连接到 Oracle 数据库并查询数据表中的记录：
```jsp
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@ page import="java
.sql
.*" %>
<html>
<head><title>Oracle Database Query</title></head>
<body>
<%
String result = "";
String sql = "SELECT * FROM employees";
String url = "jdbc:oracle:thin:@localhost:1521:orcl";
String username = "hr"; // 替换为实际用户名
String password = "hrpass"; // 替换为实际密码
try {
Class
.forName("oracle
.jdbc
.driver
.OracleDriver")
.newInstance();
Connection conn = DriverManager
.getConnection(url, username, password);
Statement stmt = conn
.createStatement();
ResultSet rs = stmt
.executeQuery(sql);
while (rs
.next()) {
result += "<br/>Employee ID: " + rs
.getInt("employee_id") +
", Name: " + rs
.getString("first_name") + " " + rs
.getString("last_name");
}
rs
.close();
stmt
.close();
conn
.close();
} catch (Exception e) {
result = "Error: " + e
.getMessage();
}
%>
<h3>Query Results:</h3>
<pre><%=result%></pre>
</body>
</html>
```
此代码片段实现了对 `employees` 表的数据读取功能[^1]。
---
#### MySQL 数据库连接与查询
对于 MySQL 数据库，可以采用类似的逻辑实现连接和查询操作。下面是一段具体的代码示例：
```jsp
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@ page import="java
.sql
.*" %>
<html>
<head><title>MySQL Database Query</title></head>
<body>
<%
String result = "";
String sql = "SELECT id, name FROM users";
String url = "jdbc:mysql://localhost:3306/testdb?useSSL=false&serverTimezone=UTC";
String username = "root"; // 替换为实际用户名
String password = "password"; // 替换为实际密码
try {
Class
.forName("com
.mysql
.cj
.jdbc
.Driver")
.newInstance();
Connection conn = DriverManager
.getConnection(url, username, password);
Statement stmt = conn
.createStatement();
ResultSet rs = stmt
.executeQuery(sql);
while (rs
.next()) {
result += "<br/>User ID: " + rs
.getInt("id") +
", Name: " + rs
.getString("name");
}
rs
.close();
stmt
.close();
conn
.close();
} catch (Exception e) {
result = "Error: " + e
.getMessage();
}
%>
<h3>Query Results:</h3>
<pre><%=result%></pre>
</body>
</html>
```
这段代码适用于 MySQL 数据库环境下的简单查询需求[^2]。
---
#### Sybase 数据库连接与查询
如果目标数据库是 Sybase，则可以通过调整驱动类名及相关参数来完成配置。下面是具体实现方式的一个例子：
```jsp
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@ page import="java
.sql
.*, java
.util
.Properties" %>
<html>
<head><title>Sybase Database Query</title></head>
<body>
<%
String result = "";
String sql = "SELECT column1, column2 FROM sample_table";
String url = "jdbc:sybase:Tds:localhost:5007/sample_db";
Properties props = new Properties();
props
.setProperty("user", "syb_user");
props
.setProperty("password", "syb_pass");
try {
Class
.forName("com
.sybase
.jdbc
.SybDriver")
.newInstance();
Connection conn = DriverManager
.getConnection(url, props);
Statement stmt = conn
.createStatement(ResultSet
.TYPE_SCROLL_SENSITIVE,
ResultSet
.CONCUR_READ_ONLY);
ResultSet rs = stmt
.executeQuery(sql);
while (rs
.next()) {
result += "<br/>Column1 Value: " + rs
.getString("column1") +
", Column2 Value: " + rs
.getString("column2");
}
rs
.close();
stmt
.close();
conn
.close();
} catch (Exception e) {
result = "Error: " + e
.getMessage();
}
%>
<h3>Query Results:</h3>
<pre><%=result%></pre>
</body>
</html>
```
该脚本能够处理来自 Sybase 的基本 SELECT 请求[^3]。
---
#### DB2 数据库连接与查询
最后介绍的是 IBM DB2 数据库的操作方法。这里给出一段标准流程作为参考依据之一：
```jsp
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@ page import="java
.sql
.*" %>
<html>
<head><title>DB2 Database Query</title></head>
<body>
<%
String result = "";
String sql = "SELECT empno, firstname, lastname FROM employee";
String dbDriver = "COM
.ibm
.db2
.jdbc
.app
.DB2Driver";
String connStr = "jdbc:db2:sample_db";
try {
Class
.forName(dbDriver)
.newInstance();
Connection conn = DriverManager
.getConnection(connStr, "db2admin", "db2pwd");
Statement stmt = conn
.createStatement();
ResultSet rs = stmt
.executeQuery(sql);
while (rs
.next()) {
result += "<br/>EmpNo: " + rs
.getString("empno") +
", First Name: " + rs
.getString("firstname") +
", Last Name: " + rs
.getString("lastname");
}
rs
.close();
stmt
.close();
conn
.close();
} catch (Exception e) {
result = "Error: " + e
.getMessage();
}
%>
<h3>Query Results:</h3>
<pre><%=result%></pre>
</body>
</html>
```
上述内容涵盖了多种主流关系型数据库管理系统上的应用实践案例[^3]。
---
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