JSP——连接数据库、编写api接口

1. 创建容器，这里用的是tomcat

window配置tomcat

2. jsp头部引入所需的包、可以从maven官网中下载对应jar包

<%@ page contentType="text/html; charset=utf-8" language="java" import="java.sql.*,java.util.*,com.alibaba.fastjson.JSON" pageEncoding="utf-8"%>

所需的jar包、可以从maven官网搜索下载

Maven官网地址：https://mvnrepository.com/

mysql-connector-java
fastjson

如：mysql-connector-java

下载后的jar包放到tomcat的lib目录或者WEB-INF的lib目录

3. 数据库配置、操作

查询使用-executeQuery(sql) 返回类型：ResultSet
增删改使用-executeUpdate(sql) 返回类型：int
Mysql常用语句：https://blog.csdn.net/qq812457115/article/details/125152133

<%@ page contentType="text/html; charset=utf-8" language="java" import="java.sql.*,java.util.*,com.alibaba.fastjson.JSON" pageEncoding="utf-8"%>
<%  
  //驱动程序名  
  String driverName = "com.mysql.jdbc.Driver";  
  //数据库用户名  
  String userName = "root";  
  //密码  
  String userPasswd = "sxj795795";  
  //数据库名  
  String dbName = "test-jsp";  
  //表名  
  String tableName = "user";  
  //联结字符串  
  String url = "jdbc:mysql://localhost/" + dbName + "?user=" + userName + "&password=" + userPasswd;  
  //加载驱动  
  Class.forName(driverName).newInstance();
  //建立连接  
  Connection conn = DriverManager.getConnection(url);
  //创建Statement（负责执行sql语句）  
  Statement stmt = conn.createStatement();  
  String sql = "select * from " + tableName;
  ResultSet rs = stmt.executeQuery(sql);
  while(rs.next())  
  {  
  	out.println(rs.getString("name"))
  }
  //关闭连接  
  rs.close();  
  stmt.close();  
  conn.close();  
%>

4. 接收传递的参数、输出参数

<%  
  // 获取name参数
  String name = request.getParameter("name");

  // 输出name参数
  out.println(name);
  
  
  response.setHeader("Access-Control-Allow-Origin", "*");  
  
  response.setHeader("Access-Control-Allow-Methods", "*");  
  
  response.setHeader("Access-Control-Max-Age", "3600");  
  
  response.setHeader("Access-Control-Allow-Headers", "*");  
  
  response.setHeader("Access-Control-Allow-Credentials", "true");
%>