JDBC优化

一.什么是dao 二.dao模式实现 三.dao优化 定义包的模式如下： TecDao package dao;import java.sql.SQLException;import java.util.List;import pojo.TecPojo;public interface TecDao {public int insert(TecPojo tec)throws SQLException;public int delet

一.什么是dao

二.dao模式实现

三.dao优化

定义包的模式如下：

TecDao

package dao;import java.sql.SQLException;import java.util.List;import pojo.TecPojo;public interface TecDao {	public int insert(TecPojo tec)throws SQLException;	public int delete(int id)throws SQLException;	public int update(TecPojo tec)throws SQLException;	public List query(TecPojo tec)throws SQLException;}

TecDaoImpl

package dao.impl;import java.sql.Connection;import java.sql.PreparedStatement;import java.sql.ResultSet;import java.sql.SQLException;import java.util.ArrayList;import java.util.List;import dao.TecDao;import pojo.TecPojo;import util.SQLUtil;public class TecDaoImpl implements TecDao{		public int insert(TecPojo tec) throws SQLException {		Connection conn = SQLUtil.getConnection();		String sql = "insert into tec (name,age,gender,job,createDate)values(?,?,?,?,?)";		PreparedStatement state = conn.prepareStatement(sql);		state.setString(1, tec.getName());		state.setInt(2, tec.getAge());		state.setString(3, tec.getGender());		state.setString(4, tec.getJob());		state.setString(5, tec.getCreateDate());		int result = state.executeUpdate();		if(result>0){			System.out.println("Yes");		}		return result;	}	public int update(TecPojo tec) throws SQLException {		Connection conn = SQLUtil.getConnection();		String sql = "update tec set name = ?,age = ? where id = 11";		PreparedStatement state = conn.prepareStatement(sql);		state.setString(1, tec.getName());		state.setInt(2, tec.getAge());		int result = state.executeUpdate();		if(result>0){			System.out.println("Yes");		}		return result;	}	public List query(TecPojo tec) throws SQLException {		Connection conn = SQLUtil.getConnection();		String sql = "select * from tec";		PreparedStatement state = conn.prepareStatement(sql);		ResultSet resultset = state.executeQuery();		ArrayList list = new ArrayList();		TecPojo tp = null;		while(resultset.next()){			tp = new TecPojo();			tp.setId(resultset.getInt("id"));			tp.setName(resultset.getString("name"));			tp.setAge(resultset.getInt("age"));			tp.setGender(resultset.getString("gender"));			tp.setJob(resultset.getString("job"));			t<b>本文来源gao@dai!ma.com搞$代^码!网7</b>p.setCreateDate(resultset.getString("createDate"));			list.add(tp);		}		for(int i = 0;i0){			System.out.println("Yes");		}		return result;	}}

TecPojo

package pojo;public class TecPojo {	private int id;	private String name;	private int age;	private String gender;	private String job;	private String createDate;	public TecPojo(String name, int age, String gender, String job, String createDate) {		super();		this.name = name;		this.age = age;		this.gender = gender;		this.job = job;		this.createDate = createDate;	}		public int getId() {		return id;	}	public void setId(int id) {		this.id = id;	}	public String toString() {		return id+" "+name+" "+age+" "+gender+" "+job+" "+createDate;	}	public TecPojo() {		super();	}	public String getName() {		return name;	}	public void setName(String name) {		this.name = name;	}	public int getAge() {		return age;	}	public void setAge(int age) {		this.age = age;	}	public String getGender() {		return gender;	}	public void setGender(String gender) {		this.gender = gender;	}	public String getJob() {		return job;	}	public void setJob(String job) {		this.job = job;	}	public String getCreateDate() {		return createDate;	}	public void setCreateDate(String createDate) {		this.createDate = createDate;	}}

SQLUtil

package util;import java.io.InputStream;import java.sql.Connection;import java.sql.DriverManager;import java.sql.SQLException;import java.util.Properties;public class SQLUtil {	private static String url;	private static String user;	private static String password;	private static String driver;	static{		try {			Properties pro = new Properties();			InputStream ins = SQLUtil.class.getResourceAsStream("/sqlconfig.properties");			pro.load(ins);			url = pro.getProperty("url");			user = pro.getProperty("user");			password = pro.getProperty("password");			driver = pro.getProperty("driver");			Class.forName(driver);		} catch (Exception e) {			e.printStackTrace();		}	}	public static Connection getConnection(){		Connection conn = null;		try {			conn = DriverManager.getConnection(url,user,password);		} catch (SQLException e) {			e.printStackTrace();		}		return conn;	}}

Test

package util;import java.sql.SQLException;import dao.impl.TecDaoImpl;import pojo.TecPojo;public class Test {	public static void main(String[] args) {		SQLUtil util = new SQLUtil();		TecPojo tp = new TecPojo("bb",22,"man","teacher","2016-4-6");		TecDaoImpl tdi = new TecDaoImpl();		try {//			tdi.insert(tp);//			tdi.update(tp);			tdi.query(tp);//			tdi.delete(12);		} catch (SQLException e) {			e.printStackTrace();		}	}}

此时发现，TecDaoImpl的方法有多次重复，于是对重复的方法再次进行封装

SQLTemplete

package util;import java.sql.Connection;import java.sql.PreparedStatement;import java.sql.ResultSet;import java.sql.SQLException;public class SQLTemplete {	public static int update(String sql,Object...object)throws SQLException{		Connection conn = SQLUtil.getConnection();		PreparedStatement state = conn.prepareStatement(sql);		for(int i=0;i<object.length;i++){			state.setObject(i+1, object[i]);		}		int result = state.executeUpdate();		return result;	}	public static ResultSet query(String sql,Object...object)throws SQLException{		Connection conn = SQLUtil.getConnection();		PreparedStatement state = conn.prepareStatement(sql);		for(int i=0;i<object.length;i++){			state.setObject(i+1, object[i]);		}		ResultSet resultset = state.executeQuery();		return resultset;	}}

TecDaoImpl

package dao.impl;import java.sql.Connection;import java.sql.PreparedStatement;import java.sql.ResultSet;import java.sql.SQLException;import java.util.ArrayList;import java.util.List;import dao.TecDao;import pojo.TecPojo;import util.SQLTemplete;import util.SQLUtil;public class TecDaoImpl implements TecDao{		public int insert(TecPojo tec) throws SQLException {		String sql = "insert into tec (name,age,gender,job,createDate)values(?,?,?,?,?)";		int result = SQLTemplete.update(sql, tec.getName(),tec.getAge(),tec.getGender(),tec.getJob(),tec.getCreateDate());		if(result>0){			System.out.println("Yes");		}		return result;	}	public int update(TecPojo tec) throws SQLException {		String sql = "update tec set name = ?,age = ? where id = 11";		int result = SQLTemplete.update(sql, tec.getName(),tec.getAge());		if(result>0){			System.out.println("Yes");		}		return result;	}	public List query(TecPojo tec) throws SQLException {		String sql = "select * from tec";		ResultSet resultset = SQLTemplete.query(sql);		ArrayList list = new ArrayList();		TecPojo tp = null;		while(resultset.next()){			tp = new TecPojo();			tp.setId(resultset.getInt("id"));			tp.setName(resultset.getString("name"));			tp.setAge(resultset.getInt("age"));			tp.setGender(resultset.getString("gender"));			tp.setJob(resultset.getString("job"));			tp.setCreateDate(resultset.getString("createDate"));			list.add(tp);		}		for(int i = 0;i0){			System.out.println("Yes");		}		return result;	}}

这样实现了更彻底的封装，TecDaoImpl类里没有直接和数据库联系，用SQLTemplete类实现对数据库的操作，从而达到业务逻辑和数据访问之间的分离。

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