第十七天：jdbc连接mysql数据库完成增删改查功能！

完成一次查询一定要关闭流，关闭流，关闭流！

package com.dao;

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

import Utils.Utils;

import com.entity.User;

public class UserDaoImpl implements UserDaoInterf {
	//根据姓名查找
	@Override
	public User findUserByName(String name1) throws ClassNotFoundException, SQLException {
		// TODO Auto-generated method stub
			User user = null;
			String sql="select * from user where name='"+name1+"'";
			Connection conn=Utils.getConn();
			Statement st=conn.createStatement();
			ResultSet set=st.executeQuery(sql);
			while(set.next()){
				int id=set.getInt(1);
				String name=set.getString(2);
				String pwd=set.getString(3);
				user=new User(id,name,pwd);
			}
			conn.close();
			set.close();
			st.close();
			return user;
	}
	//增加用户
	@Override
	public void saveUser(int id,String name, String pwd) throws ClassNotFoundException, SQLException {
		// TODO Auto-generated method stub
		String sql="insert into user  values('"+id+"','"+name+"','"+pwd+"')";
		Connection conn=Utils.getConn();
		Statement st=conn.createStatement();
		st.executeUpdate(sql);
	}
	//修改密码
	@Override
	public void updateUser(String name,String pwd) throws ClassNotFoundException, SQLException {
		// TODO Auto-generated method stub
		String sql="update user set pwd='"+pwd+"' where name='"+name+"'";
		Connection  conn=Utils.getConn();
		Statement st=conn.createStatement();
		st.executeUpdate(sql);
	}

	@Override
	public void deleteUser(String name) throws ClassNotFoundException, SQLException {
		// TODO Auto-generated method stub
		String sql="delete from user where name='"+name+"'";
		Connection conn=Utils.getConn();
		Statement st=conn.createStatement();
		st.executeUpdate(sql);
	}
}

    接口如下：

package com.dao;

import java.sql.SQLException;

import com.entity.User;

public interface UserDaoInterf {
	//根据名字查询
	public User findUserByName(String name) throws ClassNotFoundException, SQLException;
	//增加用户
	public void saveUser(int id,String name,String pwd) throws ClassNotFoundException, SQLException;
	//修改密码
	public void updateUser(String name,String pwd) throws ClassNotFoundException, SQLException;
	//删除用户
	public void deleteUser(String name) throws ClassNotFoundException, SQLException;
}

数据库映射的UserBean类如下：

package com.entity;

public class User {
	//属性
	private int id;
	private String name;
	private String passWorld;
	
	/**
	 * @param id
	 * @param name
	 * @param passWorld
	 */
	public User(int id, String name, String passWorld) {
		super();
		this.id = id;
		this.name = name;
		this.passWorld = passWorld;
	}
	//getter,setter方法
	public int getId() {
		return id;
	}
	public void setId(int id) {
		this.id = id;
	}
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	public String getPassWorld() {
		return passWorld;
	}
	public void setPassWorld(String passWorld) {
		this.passWorld = passWorld;
	}
	@Override
	public int hashCode() {
		final int prime = 31;
		int result = 1;
		result = prime * result + id;
		result = prime * result + ((name == null) ? 0 : name.hashCode());
		result = prime * result
				+ ((passWorld == null) ? 0 : passWorld.hashCode());
		return result;
	}
	@Override
	public boolean equals(Object obj) {
		if (this == obj)
			return true;
		if (obj == null)
			return false;
		if (getClass() != obj.getClass())
			return false;
		User other = (User) obj;
		if (id != other.id)
			return false;
		if (name == null) {
			if (other.name != null)
				return false;
		} else if (!name.equals(other.name))
			return false;
		if (passWorld == null) {
			if (other.passWorld != null)
				return false;
		} else if (!passWorld.equals(other.passWorld))
			return false;
		return true;
	}
	@Override
	public String toString() {
		return "User [id=" + id + ", name=" + name + ", passWorld=" + passWorld
				+ "]";
	}
}