Servlet+JDBC+Mysql简单班级信息增添和遍历显示

项目结构：

数据库设计：

首先建立JDBC连接数据库：

DBUtil：

package com.util;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

public class DBUtil {
	static {
		//加载数据库驱动
		try {
			Class.forName("com.mysql.cj.jdbc.Driver");
		} catch (ClassNotFoundException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
	}
	public static Connection getConnection () {
		Connection conn=null;
		//获取数据库链接
		try {
			conn=DriverManager
					.getConnection("jdbc:mysql://localhost:3306/wenbin?" + 
												"useSSL=false&serverTimezone=GMT","root","120831");
		} catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		return conn;
	}
	
	//关闭相关链接
	public static void release(Connection conn,Statement stmt,ResultSet rs) {
		if (conn!=null) {
			
		
		try {
			conn.close();
		} catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		}
		if (stmt!=null) {
			try {
				stmt.close();
			} catch (SQLException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
		}
		if (rs!=null) {
			try {
				rs.close();
			} catch (SQLException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
		}
	}

}

建立和数据库对应的类：

classInfoBean:

package com.bean;

public class classInfoBean {
	/**
	 * 属性和数据库中的字段相对应
	 * 
	 */
	private int cid;
	private String cname;
	public classInfoBean() {
		super();
	}
	public int getCid() {
		return cid;
	}
	public void setCid(int cid) {
		this.cid = cid;
	}
	public String getCname() {
		return cname;
	}
	public void setCname(String cname) {
		this.cname = cname;
	}
	@Override
	public String toString() {
		return "classInfoBean [cid=" + cid + ", cname=" + cname + "]";
	}

}

数据库操作：

classInfoDao:

package com.dao;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.ArrayList;
import java.util.List;

import javax.management.RuntimeErrorException;

import com.entiry.classInfoBean;

public class classInfoDao {
	static {
		//加载数据库驱动
		try {
			Class.forName("com.mysql.cj.jdbc.Driver");
		} catch (ClassNotFoundException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		
	}
	public void addClassInfo(classInfoBean bean) {
		Connection conn=null;
		Statement stmt=null;
		//获取数据库链接
		try {
			conn=DriverManager.getConnection("jdbc:mysql://localhost:3306/wenbin?"
					+ "useSSL=false&serverTimezone=GMT","root","120831");
			//整理一条sql语句
			String sql="insert into class_info (cname) values('"
					+bean.getCname()+ "')";
			//创建sql执行对象
			stmt=conn.createStatement();
			//执行sql语句
			int row=stmt.executeUpdate(sql);
			if (row!=1) {
				throw new RuntimeException( "新增班级失败");
			}
		} catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		finally {
			if (conn!=null) {
				try {
					conn.close();
				} catch (SQLException e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				}
			}
			if (stmt!=null) {
				try {
					stmt.close();
				} catch (SQLException e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				}
			}
		}
	}
	
	public List<classInfoBean> findAll(){
		Connection conn=null;
		Statement stmt=null;
		List<classInfoBean> classList=new ArrayList<classInfoBean>();
		try {
			conn=DriverManager.getConnection("jdbc:mysql://localhost:3306/wenbin?"
					+ "useSSL=false&serverTimezone=GMT","root","120831");
			//整理一条sql语句
			String sql="select cid,cname from class_info";	
			//创建sql执行对象
			stmt=conn.createStatement();
			ResultSet rs=stmt.executeQuery(sql);
			//遍历结果集
			while(rs.next()) {
				int cid=rs.getInt("cid");
				String cname=rs.getString("cname");
			classInfoBean bean=new classInfoBean();
			bean.setCid(cid);
			bean.setCname(cname);
			classList.add(bean);
			}
		} catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
	}
		return classList;

	}
	
}

Servlet操作

ClassInfoServlet:

package com.servlet;

import java.io.IOException;
import java.util.List;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import com.dao.classInfoDao;
import com.entiry.classInfoBean;

/**
 * Servlet implementation class ClassInfoServlet
 */
public class ClassInfoServlet extends HttpServlet {
	private static final long serialVersionUID = 1L;
       
    /**
     * @see HttpServlet#HttpServlet()
     */
    public ClassInfoServlet() {
        super();
        // TODO Auto-generated constructor stub
    }

	/**
	 * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
	 */
	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		// TODO Auto-generated method stub
		response.getWriter().append("Served at: ").append(request.getContextPath());
	}

	/**
	 * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
	 */
	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
	    //设置编码，防止请求乱码
		request.setCharacterEncoding("utf-8");
		//获取参数
		String className=request.getParameter("className");
		//创建classInfoBean对象保存信息
		classInfoBean bean=new classInfoBean();
		bean.setCname(className);
		//创建数据库操作对象
		classInfoDao dao=new classInfoDao();
		//新增班级信息到数据库
		dao.addClassInfo(bean);
		//查询所有班级信息
		List<classInfoBean> classInfo=dao.findAll();
		//保存
		request.setAttribute("classInfo", classInfo);
	    //转发请求
		request.getRequestDispatcher("/classInfo.jsp").forward(request,response );
	}

}