userservice.java

JSP写的一个简单聊天室。不需要连接数据库。实现简单

package service;

import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;

import model.User;

import database.DataBase;
public class UserService {
	
	private DataBase db;
	
	public UserService() {
		db = new DataBase();
	}
	//验证用户的合法性
	public boolean checkUser(String name,String password){
		String sql="select * from user where nickname='"+name+"' and password='"+password+"'";
		String sql2="update user set online='1' where nickname='"+name+"'";
		ResultSet rs = db.executeQuery(sql);
		System.out.println(sql);
		try {
			if(rs.next())
			{
				db.executeUpdate(sql2);
			return true;
			}
		} catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		db.closeStmt();
		db.closeConn();
		return false;
	}
	//验证用户名是否可用
	public boolean addUser(String name,String password,String sex,String email,String qq){
		boolean b = false;
		String sql = "select * from user where nickname = '" + name + "'";
		String sql2 = "insert into user values('" + name+ "','" + password + "','" + sex+ "','" + email+ "','" + qq+ "','0')";
		ResultSet rs = db.executeQuery(sql);
		try {
			if (rs.next()) {
				b = false;
			} else {
				if(name==null||password==null) b=false;
				else
				b=db.executeUpdate(sql2);
			}
		} catch (Exception e) {
			e.printStackTrace();
			b=false;
		}
		db.closeStmt();
		db.closeConn();
		return b;
	}
	//通过online查找在线人数,把它存在Arraylist数组中
	public List getOnlineNames(){
		List users = new ArrayList();
		String sql="select * from user where online='1'";
		ResultSet rs=db.executeQuery(sql);
		User user=null;
		try {
			while(rs.next()){
				user = new User();
				user.setNickname(rs.getString("nickname"));
				users.add(user);
			}
			
		} catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		db.closeStmt();
		db.closeConn();
		return users;
	}
	//返回在线人数的个数
	public int getNum(){
		String sql="select count(*) num from user where online='1'";
		int num = 0;
		ResultSet rs=db.executeQuery(sql);
		try {
			while(rs.next()){
				num=rs.getInt("num");
			}
		} catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		db.closeStmt();
		db.closeConn();
		return num;
	}
	//退出时将在线状态更改
	public boolean exit(String name){
		String sql="update user set online='0' where nickname='"+name+"'";
		boolean b = db.executeUpdate(sql);
		db.closeStmt();
		db.closeConn();
		return b;
	}
}