JavaWeb—优化JDBC代码

方法一：【工具类】

NewDao：

	String sql = "select * from t1";
	DbUtils db = new DbUtils();
	Connection conn = null;
	ResultSet rs = null;
	Statement stmt = null;
	
	public void getNewsList() {
		conn = db.getConnection();
		try {
			Statement stms = (Statement) conn.createStatement();
			rs = stms.executeQuery(sql);
			while(rs.next()){
				String title = rs.getString("name");
				System.out.println("title=="+title);
			}
		} catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		db.close(rs, stmt, conn);
	}

DbUtils：

String url = "jdbc:mysql://localhost:3306/news";
	String user = "root";
	String password = "3838438";
	
	public Connection getConnection() {
		Connection conn = null;
		try {
			Class.forName("com.mysql.jdbc.Driver");
			conn = (Connection) DriverManager.getConnection(url,user,password);
		}catch(ClassNotFoundException e) {
			e.printStackTrace();
		} catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		return conn;
	}
	
	public void close(ResultSet rs,Statement stmt,Connection conn) {
		if(rs!=null){
			try {
				rs.close();
			} catch (SQLException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}			//	关闭结果集对象
		}
		if(stmt!=null){
			try {
				stmt.close();
			} catch (SQLException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}		//	关闭 Statement 对象
		}
		if(conn!=null){
			try {
				conn.close();
			} catch (SQLException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}		//	关闭连接对象
		}
	}

方法二：【利用继承与接口】

BaseDao.java

package java.util.two;

import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;

import com.mysql.jdbc.Connection;
import com.mysql.jdbc.Statement;

public class BaseDao {
	protected Connection conn;
	protected PreparedStatement ps;
	protected Statement stmt;
	protected ResultSet rs;
	
	//获取数据库链接
	public boolean getConnection() {
		return true;
	}
	//	增、删、改、查
	public int executeUpdate(String sql,Object[] params) {
		int updateRows = 0;
		return updateRows;
	}
	//	查询
	public ResultSet executeSQL(String sql,Object[] params) {
		return rs;
	}
	//关闭资源
	public boolean closeResource() {
		return true;
	}
}

NewsDao.java

package java.util.two;

import java.sql.Date;

public interface NewsDao {
	//查询新闻信息
	public void getNewsList();
	//增加新闻信息
	public void add(int id,int category,String title,String summary,String content,Date createdate);
	//删除新闻信息
	public void delete(int id);
	//修改新闻标题信息
	public void update(int id,String title);
}

NewsDaoImpl.java

package java.util.two;

import java.sql.Date;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.DbUtils;

import com.mysql.jdbc.Connection;
import com.mysql.jdbc.Statement;

public class NewsDaoImpl extends BaseDao implements NewsDao {
	String sql = "select * from t1";
	DbUtils db = new DbUtils();
	Connection conn = null;
	ResultSet rs = null;
	Statement stmt = null;;

	@Override
	public void getNewsList() {
		conn = db.getConnection();
		try {
			Statement stms = (Statement) conn.createStatement();
			rs = stms.executeQuery(sql);
			while(rs.next()){
				String title = rs.getString("name");
				System.out.println("title=="+title);
			}
		} catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		db.close(rs, stmt, conn);
	}

	@Override
	public void add(int id, int category, String title, String summary, String content, Date createdate) {
		// TODO Auto-generated method stub

	}

	@Override
	public void delete(int id) {
		// TODO Auto-generated method stub

	}

	@Override
	public void update(int id, String title) {
		// TODO Auto-generated method stub

	}

}