通过idea新建web工程在oracle数据库中读取数据并打印在页面上

本文链接：https://blog.youkuaiyun.com/weixin_47993269/article/details/120066604

1.新建web工程

2.下载驱动包：

在Maven 中央仓库查找依赖代码：

<!-- https://mvnrepository.com/artifact/com.oracle/ojdbc6 -->
<dependency>
    <groupId>com.oracle</groupId>
    <artifactId>ojdbc6</artifactId>
    <version>12.1.0.1-atlassian-hosted</version>
</dependency>

添加到pom.xml依赖中，maven自动下载驱动包（刷新maven即可）

3.添加工具类，或者编写工具类（DBUIL）和db资源包

driverclass=oracle.jdbc.driver.OracleDriver
url=jdbc:oracle:thin:@127.0.0.1:1521:orcl
name=scott
pass=123456

import java.sql.*;
import java.util.ResourceBundle;

public class DBIILE {
    public static  final String driverclass;
    public static  final String name;
    public static  final String url;
    public static  final String pass;
     static{
         ResourceBundle rb=ResourceBundle.getBundle("db");
         driverclass=rb.getString("driverclass");
         name=rb.getString("name");
         url=rb.getString("url");
         pass=rb.getString("pass");
         try {
             Class.forName(driverclass);//加载数据驱动
         } catch (ClassNotFoundException e) {
             e.printStackTrace();
         }
     }
    public static Connection open() throws  SQLException {

        Connection conn= DriverManager.getConnection(url,name,pass);//获得数据库连接
        return conn;
    }
    public static  void close(Connection conn,PreparedStatement pst){
        close(null,conn,pst);
    }
    public static  void close(ResultSet rs, Connection conn, PreparedStatement pst){
        if(rs!=null){
            try {
                rs.close();
            } catch (SQLException throwables) {
                throwables.printStackTrace();
            }
        }
        if(conn!=null){
            try {
                conn.close();
            } catch (SQLException throwables) {
                throwables.printStackTrace();
            }
        }
        if(pst!=null){
            try {
                pst.close();
            } catch (SQLException throwables) {
                throwables.printStackTrace();
            }
        }
    }
}

4.编写list 类来实现数据库连接以及用户表信息在页面输入

import javax.servlet.*;
import javax.servlet.annotation.WebServlet;
import java.io.IOException;
import java.io.PrintWriter;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
@WebServlet("/list")
public class list implements Servlet {
    //获得数据库连接




    @Override
    public void service(ServletRequest servletRequest, ServletResponse servletResponse) throws ServletException, IOException {
        String sql="select *from t_user";//查找数据库中t_user表的sql语句
        try( Connection conn=DBIILE.open();
              //PrepareStatement 对象来执行sql语句
             PreparedStatement pst=conn.prepareStatement(sql))    {
            ResultSet rs = pst.executeQuery();//接收sql语句返回的结果

            servletResponse.setContentType("text/html; charset=utf-8");//修改页面响应的编码格式和编码结果
            PrintWriter out=servletResponse.getWriter();//out来接收响应并打印到页面
            out.println("<html><head><title>用户信息</title></head><body>");
            out.println("<table border='1' width='80%'>");
            out.println("<tr><td>ID</td><td>账号</td><td>密码</td><td>姓名</td></tr>");
            while(rs.next()){
                out.println("<tr><td>"+rs.getInt("ID")+
                        "</td><td>"+rs.getString("name")+"" +
                        "</td><td>"+rs.getString("pass")+
                        "</td><td>"+rs.getString("nickname")+"</td></tr>");
            }

        } catch (SQLException throwables) {
            throwables.printStackTrace();
        }
    }

    @Override
    public void init(ServletConfig servletConfig) throws ServletException {

    }

    @Override
    public ServletConfig getServletConfig() {
        return null;
    }



    @Override
    public String getServletInfo() {
        return null;
    }

    @Override
    public void destroy() {

    }
}