javaweb配置连接mysql数据库

1、首先新建基础连接类BaseDao，在这里配置链接的数据库名称，用户名以及密码，以及执行读与写操作的父方法，代码如下：

package com.demo.dao;

import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.SQLException;
import java.util.List;

/**
 * 数据库操作类
 * @author zhangdi
 *
 */

public class BaseDao {

    //数据库地址“jdbc:mysql://服务器域名:端口号/数据库名称”
    private String url = "jdbc:mysql://127.0.0.1:3306/mydb?useUnicode=true&characterEncoding=utf-8";
    //用户名
    private String user = "root";
    //用户密码
    private String pwd = "zhangdi";
    //数据库链接对象
    private java.sql.Connection conn;
    //数据库命令执行对象
    private PreparedStatement pstmt;
    //数据库返回结果
    private java.sql.ResultSet rs;
    
    //静态代码块
    static{
        //1、加载驱动
        try {
            Class.forName("com.mysql.jdbc.Driver");
        } catch (ClassNotFoundException e) {
            
            e.printStackTrace();
        }
    }
    
    //2、创建连接
    private void getConnection(){
        if(conn == null){
            try {
                conn = DriverManager.getConnection(url, user, pwd);
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
    }
    
    //执行读操作方法
    public java.sql.ResultSet executeQuery(String query,
                    List<Object> params){
        getConnection();
        try {
            //3、创建命令执行对象
            pstmt = conn.prepareStatement(query);
            //4、执行
            if(params!=null && params.size()>0){
                for(int i=0;i<params.size();i++){
                    pstmt.setObject(i+1, params.get(i));
                }
            }
            rs = pstmt.executeQuery();
        } catch (SQLException e) {
            e.printStackTrace();
        }
        return rs;
    }
    
    //执行写操作方法
    public int executeUpdate(String query,
            List<Object> params){
        int result = 0;
        getConnection();
        try {
            //3、创建命令执行对象
            pstmt = conn.prepareStatement(query);
            //4、执行
            if(params!=null && params.size()>0){
                for(int i=0;i<params.size();i++){
                    pstmt.setObject(i+1, params.get(i));
                }
            }
            //5、处理结果
            result = pstmt.executeUpdate();
        } catch (SQLException e) {
            e.printStackTrace();
        }finally{
            //6、释放资源
            this.close();
        }
        return result;
    }

    
    //关闭资源
    public void close(){        
            try {
                if(rs!=null){
                    rs.close();
                    rs = null;
                }
                if(pstmt!=null){
                    pstmt.close();
                    pstmt = null;
                }
                if(conn!=null){
                    conn.close();
                    conn = null;
                }
            } catch (SQLException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        
        }

}

2、第二步，就创建一个数据库操作接口类，采用面向接口的开发思想以便于后期维护，代码如下：

package com.demo.dao;

import java.util.List;

import com.demo.entity.User;

public interface UserDao {
    public int addUser(User user);
    public List<User> findUsers();
    public List<User> findUsers(String name);
    public List<User> findUsersByDept(String dept);
    public List<User> findUsersByRole(String role);
    public int delUserById(int id);
    public int updateUserById(int id,User role);
    public boolean checkUser(String name);
}

3、第三步创建数据库操作对象接口实现类并继承数据库操作基础类：

package com.demo.daoimpl;

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

import com.demo.dao.BaseDao;
import com.demo.dao.DeptDao;
import com.demo.dao.RoleDao;
import com.demo.dao.UserDao;
import com.demo.entity.User;

public class UserDaoImpl extends BaseDao implements UserDao {
    DeptDao deptDao = new DeptDaoImpl();
    RoleDao roleDao = new RoleDaoImpl();
    //添加一条用户信息
    @Override
    public int addUser(User user) {
        String update = "insert into users(account,pwd,NAME,dept,role,phone,qq,email,remark)values(?,?,?,?,?,?,?,?,?)";
        List<Object> params = new ArrayList<Object>();
        params.add(user.getAccount());
        params.add(user.getPwd());
        params.add(deptDao.returnDeptIdByName(user.getDept()));
        params.add(roleDao.returnRoleIdByName(user.getRole()));
        params.add(user.getRole());
        params.add(user.getPhone());
        params.add(user.getQq());
        params.add(user.getEmail());
        params.add(user.getMark());
        return this.executeUpdate(update, params);
    }

    @Override
    public List<User> findUsers() {
        List<User> result = new ArrayList<User>();
        String query = "select id,account,pwd,NAME,dept,role,phone,qq,email,remark from users";
        ResultSet rs = this.executeQuery(query, null);
        try {
            while(rs.next()){
                int id = rs.getInt("id");
                String account = rs.getString("account");
                String pwd = rs.getString("pwd");
                String name = rs.getString("NAME");
                String dept = deptDao.returnDeptNameById(rs.getInt("dept"));
                String role = roleDao.returnRoleNameById(rs.getInt("role"));
                String phone ="11";//+ rs.getInt("phone");
                String qq = "22";//+rs.getInt("qq");
                String email = rs.getString("email");
                String mark = rs.getString("remark");
                User user = new User(id, account,pwd,name,dept,role,phone,qq,email,mark);
                result.add(user);
            }
        } catch (SQLException e) {
            e.printStackTrace();
        }finally{
                this.close();
        }
        return result;
    }

    @Override
    public List<User> findUsersByDept(String dept) {
        List<User> result = new ArrayList<User>();
        List<Object> params = new ArrayList<Object>();
        String query = "select id,account,pwd,NAME,dept,role,phone,qq,email,remark from users where dept =?";
        if(dept!=null&&!"".equals(dept)){
            int d = deptDao.returnDeptIdByName(dept);
            params.add(d);
        }
        ResultSet rs = this.executeQuery(query, params);
        try {
            while(rs.next()){
                int id = rs.getInt("id");
                String account = rs.getString("account");
                String pwd = rs.getString("pwd");
                String name = rs.getString("NAME");
                String deptName = deptDao.returnDeptNameById(rs.getInt("dept"));
                String role = roleDao.returnRoleNameById(rs.getInt("role"));
                String phone = Integer.toString(rs.getInt("phone"));
                String qq = Integer.toString(rs.getInt("qq"));
                String email = rs.getString("email");
                String mark = rs.getString("remark");
                User user = new User(id, account,pwd,name,deptName,role,phone,qq,email,mark);
                result.add(user);
            }
        } catch (SQLException e) {
            e.printStackTrace();
        }finally{
                this.close();
        }
        return result;
    }

    @Override
    public List<User> findUsersByRole(String role) {
        List<User> result = new ArrayList<User>();
        List<Object> params = new ArrayList<Object>();
        String query = "select id,account,pwd,NAME,dept,role,phone,qq,email,remark from users where role =?";
        if(role!=null&&!"".equals(role)){
            int d = roleDao.returnRoleIdByName(role);
            params.add(d);
        }
        ResultSet rs = this.executeQuery(query, params);
        try {
            while(rs.next()){
                int id = rs.getInt("id");
                String account = rs.getString("account");
                String pwd = rs.getString("pwd");
                String name = rs.getString("NAME");
                String deptName = deptDao.returnDeptNameById(rs.getInt("dept"));
                String roleName = roleDao.returnRoleNameById(rs.getInt("role"));
                String phone = Integer.toString(rs.getInt("phone"));
                String qq = Integer.toString(rs.getInt("qq"));
                String email = rs.getString("email");
                String mark = rs.getString("remark");
                User user = new User(id, account,pwd,name,deptName,roleName,phone,qq,email,mark);
                result.add(user);
            }
        } catch (SQLException e) {
            e.printStackTrace();
        }finally{
                this.close();
        }
        return result;
    }

    @Override
    public int delUserById(int id) {
        String query = "delete from users where id = ?";
        List<Object> params = new ArrayList<Object>();
        params.add(id);
        return this.executeUpdate(query, params);
    }

    @Override
    public int updateUserById(int id, User role) {
        // TODO Auto-generated method stub
        return 0;
    }

    @Override
    public boolean checkUser(String name) {
        List<User> list = new ArrayList<User>();
        list = this.findUsers();
        for(User u:list){
            if(u.getName().equals(name)){
                return true;
            }
        }
        return false;
    }

    @Override
    public List<User> findUsers(String name) {
        List<User> result = new ArrayList<User>();
        List<Object> params = new ArrayList<Object>();
        String query = "select id,account,pwd,NAME,dept,role,phone,qq,email,remark from users where 1=1";
        if(name!=null&&!"".equals(name)){
            query = query+" and NAME like ?";
            params.add("%"+name+"%");
        }
        ResultSet rs = this.executeQuery(query, params);
        try {
            while(rs.next()){
                int id = rs.getInt("id");
                String n = rs.getString("name");
                String desc = rs.getString("desc");
                User user = new User();
                result.add(user);
            }
        } catch (SQLException e) {
            e.printStackTrace();
        }finally{
                this.close();
        }
        return result;
    }

}

这里面role与dept也是两个数据库操作类，大家可以忽略，其中User为实体类，代码如下：

package com.demo.entity;

public class User {
    private int id;
    private String account;
    private String pwd;
    private String name;
    private String dept;
    private String role;
    private String phone;
    private String qq;
    private String mark;
    private String email;
    
    
    
    public String getEmail() {
        return email;
    }
    public void setEmail(String email) {
        this.email = email;
    }
    public int getId() {
        return id;
    }
    public void setId(int id) {
        this.id = id;
    }
    public String getAccount() {
        return account;
    }
    public void setAccount(String account) {
        this.account = account;
    }
    public String getPwd() {
        return pwd;
    }
    public void setPwd(String pwd) {
        this.pwd = pwd;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public String getDept() {
        return dept;
    }
    public void setDept(String dept) {
        this.dept = dept;
    }
    public String getRole() {
        return role;
    }
    public void setRole(String role) {
        this.role = role;
    }
    public String getPhone() {
        return phone;
    }
    public void setPhone(String phone) {
        this.phone = phone;
    }
    public String getQq() {
        return qq;
    }
    public void setQq(String qq) {
        this.qq = qq;
    }
    public String getMark() {
        return mark;
    }
    public void setMark(String mark) {
        this.mark = mark;
    }
    public User() {
        super();
        // TODO Auto-generated constructor stub
    }
    public User(int id, String account, String pwd, String name, String dept,
            String role, String phone, String qq, String mark, String email) {
        super();
        this.id = id;
        this.account = account;
        this.pwd = pwd;
        this.name = name;
        this.dept = dept;
        this.role = role;
        this.phone = phone;
        this.qq = qq;
        this.mark = mark;
        this.email = email;
    }
    public User(String account, String pwd, String name,int id) {
        super();
        this.account = account;
        this.pwd = pwd;
        this.name = name;
        this.id = id;
    }
    
}

至此，web后台与mysql数据库的链接就完成了，如果要执行对数据库的操作就调用数据库操作类即可。

注：这里需要引用的jar包为：

这些为项目基础jar包：