eclipse web项目指引

step.1: 配置好eclipse，java，tomcat，mysql；
step.2: 在eclipse中 new-> Dynamic Web project；输入项目名 -> next -> next -> 勾选Generate web.xml -> finish -> no;
step.3: 右键 JRE System Library[jdk] ->Build Path -> Configure Build Path - > Add External JARs… -> 导入mysql-connector-java-8.0.11.jar 包 -> Apply;
step.4: 在下方的调试框中进入"Servers"，new -> Server -> 选择你的Tomcat版本 -> next ->将左边的你想要部署的web项目add到右边 -> finish；以后便可以在"Servers"里面运行/停止web项目了;
step.5: 在java/src目录下新建一个"com.util"包(规范化)，把 "SqlData.java"包中 ，这是一个别人造的轮子；在SqlDate.java中可以修改连接数据库的用户名，密码，要连接的数据库名字等等；
step.6: 新建 配套的jsp和java：
6.1在WebContent目录下新建first.jsp文件，< body >例如：

<form action="servlet/First" method="post">
<div id="apDiv1">
  <table width="578" height="242" border="0" cellpadding="0" cellspacing="0">
    <tr>
     
      <td width="69">姓名：td>
      <td width="231"><div id="apDiv3"><input type="text" name="name" class="input-text lh30" size="25">div>td>
    tr>
    <tr>
      <td height="45">   密码：td>
      <td><div id="apDiv4"><input type="password" name="password" class="input-text lh30" size="25">div>td>
      
    tr>
  table>
  <div id="apDiv11">  <input type="submit" name="button" class="btn btn82 btn_save2" value="注册"> 
  
  div>
  
div>
form>

PS:from 的 action参数指定了表单信息的去处

6.2在java/src目录下new一个servlet，用来处理first.jsp传递的表单信息 -> Java package:com.contr; class name:First -> 直接Finish；First.java创建好后，可以引入这些东西：

import java.sql.ResultSet;
import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.annotation.WebInitParam;
import javax.swing.JOptionPane;
import com.util.SqlData;

...java

@WebServlet(
		asyncSupported = true, 
		urlPatterns = { 
				"/First", 
				"/servlet/First"
		}, 
		initParams = { 
				@WebInitParam(name = "=First", value = "com.contr")
		})
...

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

		String name = null;
		String password = null;
		
		name = request.getParameter("name");
		String name0 = new String(name.getBytes("ISO-8859-1"),"UTF-8");   //
		
		password = request.getParameter("password");
		//String password0 = new String(password.getBytes("ISO-8859-1"),"UTF-8"); //

        String sql = "insert into test(name,password)"
				+ " values('"+name0+"','"+password+"')";

		SqlData db = new SqlData();
		try {
			db.executeInsert(sql);
			JOptionPane.showMessageDialog(null, "注册成功!");
			//response.sendRedirect("../mainPage.jsp");
		} catch (Exception e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
			JOptionPane.showMessageDialog(null, "异常");
			//response.sendRedirect("../mainPage.jsp");
		}
	}

PS:我的数据库设定：用户名"root"，无密码，数据库名"db"，表名"test"，属性只有"name"和"password"(String类型)

最后附上轮子：

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 SqlData {

	Connection conn;
	String url="";
	String user="";
	String password="";
	Statement start;
	ResultSet rs;

	public SqlData() {
		url = "jdbc:mysql://localhost:3306/db?serverTimezone=UTC";//数据库名
		user="root";//用户名
		password="";//密码
		conn = null;
		start = null;
		rs = null;

		
		
		try {
			Class.forName("com.mysql.cj.jdbc.Driver");
		} catch (Exception ex) {
			ex.printStackTrace();
		}
	}

	public void executeInsert(String sql) { //
		try {
			conn = DriverManager.getConnection(url, user, password);
			start = conn.createStatement();
			start.executeUpdate(sql);
			start.close();
			conn.close();
		} catch (SQLException ex) {
			System.err.println((new StringBuilder("sql_data.executeUpdate:")).append(ex.getMessage()).toString());
		}
	}
	
	public ResultSet executeQuery(String sql){  //
		try{
			conn = DriverManager.getConnection(url, user, password);
			start = conn.createStatement(1005, 1007);
			rs = start.executeQuery(sql);
		}
		catch (SQLException ex){
			System.err.println((new StringBuilder("sql_data.executeQuery:")).append(ex.getMessage()).toString());
		}
		return rs;
	}
	public void executeUpdate(String sql){ //
		try{
			conn = DriverManager.getConnection(url, user, password);
			start = conn.createStatement();
			start.executeUpdate(sql);
			start.close();
			conn.close();
		}
		catch (SQLException ex){
			System.err.println((new StringBuilder("aq.executeQuery: ")).append(ex.getMessage()).toString());
		}
	}
	
	public void executeDelete(String sql){ //
		try{
			conn = DriverManager.getConnection(url, user, password);
			start = conn.createStatement();
			start.executeUpdate(sql);
			start.close();
			conn.close();
		}
		catch (SQLException ex){
			System.err.println((new StringBuilder("sql_data.executeDelete:")).append(ex.getMessage()).toString());
		}
	}
	
	public void closeStart() {   //
		try {
			start.close();
		} catch (SQLException e) {
			e.printStackTrace();
		}
	}

	public void closeConn() {
		try {
			conn.close();
		} catch (SQLException e) {
			e.printStackTrace();
		}
	}
	
	
	}