需求：完成用户登录页面校验
第一步：创建一个用户登录的html页面
<!DOCTYPE html> <html> <head> <meta charset="UTF-8"> <title>Insert title here</title> </head> <body> <form action="/WEB13/login" method="post"> 用户名：<input type="text" name="username" /><br/> 密码：<input type="password" name="password" /><br/> <input type="submit" value="登录"/><br/> </form> </body> </html>
第二步：导入所需要的jar包
导入jar之后记得add to bulid path.
第三步：创建c3p0连接池的配置文件，文件名为c3p0-config.xml
<?xml version="1.0" encoding="UTF-8"?> <c3p0-config> <default-config> <property name="driverClass">com.mysql.jdbc.Driver</property> <property name="jdbcUrl">jdbc:mysql:///web13</property> <property name="user">root</property> <property name="password">root</property> <property name="initialPoolSize">5</property> <property name="maxPoolSize">20</property> </default-config> <named-config name="myconfig"> <property name="driverClass">com.mysql.jdbc.Driver</property> <property name="jdbcUrl">jdbc:mysql:///web13</property> <property name="user">root</property> <property name="password">root</property> </named-config> </c3p0-config>
文件放到src目录下
第四步：创建c3p0工具类
package p1.utils; import java.sql.Connection; import java.sql.SQLException; import javax.sql.DataSource; import com.mchange.v2.c3p0.ComboPooledDataSource; public class C3P0Utils { private static ComboPooledDataSource dataSource = new ComboPooledDataSource(); public static DataSource getDataSource() { return dataSource; } public static Connection getConnection() { try { return dataSource.getConnection(); } catch (SQLException e) { throw new RuntimeException(e); } } }
第五步：创建User类
package p3.domain; public class User { private int uid; private String username; private String upassword; private String email; public User(){} public int getUid() { return uid; } public void setUid(int uid) { this.uid = uid; } public String getUsername() { return username; } public void setUsername(String username) { this.username = username; } public String getUpassword() { return upassword; } public void setUpassword(String upassword) { this.upassword = upassword; } public String getEmail() { return email; } public void setEmail(String email) { this.email = email; } @Override public String toString() { return "User [uid=" + uid + ", username=" + username + ", upassword=" + upassword + ", email=" + email + "]"; } }
第六步：编写LoginServlet类
package p2.login_servlet; import java.io.IOException; import java.sql.SQLException; import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import org.apache.commons.dbutils.QueryRunner; import org.apache.commons.dbutils.handlers.BeanHandler; import p1.utils.C3P0Utils; import p3.domain.User; public class LoginServlet extends HttpServlet { public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { //1 获取用户名和密码 String username = request.getParameter("username"); String password = request.getParameter("password"); // 2查询数据库中是否有相应的用户名和密码 QueryRunner qr = new QueryRunner(C3P0Utils.getDataSource()); String sql = "select * from user where username=? and upassword=?"; Object[] params = {username,password}; User user = null; try { user = qr.query(sql, new BeanHandler<User>(User.class), params); } catch (SQLException e) { e.printStackTrace(); } // 3 根据返回结果给用户不同的显示信息 if(user!=null){ response.getWriter().write(user.toString()); response.getWriter().write(user.getUsername()+":登录成功"); }else{ response.getWriter().write("sorry the username or password is wrong"); } } public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { doGet(request, response); } }
第七部：发布的时候如果出现找不到网页404的情况，有时候重新启动tomcat就可以了。