一.首先创建一个类，封装数据库和个人信息：
package com.yxq.dao;
public class Constants {
public static String url ="jdbc:mysql://127.0.0.1:3306/personblog";
public static String className="com.mysql.jdbc.Driver";
public static String userName ="root";
public static String password = "root";
}
以后只要修改这个类的信息；就可以了；
还要把jar包，添加到项目中；
二、封装一个类来连接数据库和关闭数据库：
package com.yxq.dao;
/*导入所需的包*/
import java.sql.Connection;//表示链接到某个数据库的链接;
import java.sql.DriverManager;//用来获取数据库链接的类;
import java.sql.ResultSet;//封装查询结果集的类;
import java.sql.SQLException;
import java.sql.Statement; //用来执行SQL语句的类;
public class DB {
// 获取数据的连接；
public static Connection getConnection() throws Exception{
try{
Class.forName(Constants.className);
Connection con = DriverManager.getConnection(Constants.url,Constants.userName,Constants.password);
return con;
}catch (Exception e) {
e.printStackTrace();
System.out.println("连接失败");
return null;
}
}
// 关闭Statement对象;
public static void closeStatement(Statement stmt) throws Exception{
try{
if(stmt !=null){
stmt.close();
System.out.println("关闭Statement成功");
}
}catch (Exception e) {
e.printStackTrace();
System.out.println("关闭Statement失败");
}
}
// 关闭ResultSet对象;
public static void closeResultSet(ResultSet rs) throws Exception{
try{
if(rs!=null){
rs.close();
System.out.println("关闭ResultSet成功");
}
}catch (Exception e) {
e.printStackTrace();
System.out.println("关闭ResultSet失败");
}
}
//关闭connection对象;
public static void closeConnection(Connection conn,Statement stm,ResultSet rs)throws Exception{
try{
if(rs!= null){
rs.close();
System.out.println("关闭rs成功");
}
if(stm != null){
stm.close();
System.out.println("关闭stm成功");
}
if(conn!=null){
conn.close();
System.out.println("关闭Connection成功");
}
}catch (Exception e) {
e.printStackTrace();
System.out.println("关闭Connection失败");
}
}
}
三.创建一个特定的类，来增删改查数据里特定的一张表;
package com.yxq.dao;
import java.sql.Connection;
import java.sql.Date;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.ArrayList;
import java.util.List;
import com.yxq.valuebean.Model_Artical;
import com.yxq.dao.DB;
public class ArticalDao {
/*
* @Description: 查询文章;
* @param :参数是start，end ,分别是数据的第几条数据，和一次查询的数量；
* @return:返回查询的记录，封装在List中。
* */
public List<Model_Artical> query(int start,int end) throws Exception{
Connection con = DB.getConnection();
Statement stm = con.createStatement();
String sql="SELECT * FROM tbl_artical limit "+start+","+end+"";
ResultSet rs= stm.executeQuery(sql);
List<Model_Artical> model_artical = new ArrayList<Model_Artical>();
Model_Artical artical= null;
while(rs.next()){
artical = new Model_Artical();
artical.setArtical_Id(rs.getInt(1));
artical.setArtical_Name(rs.getString("Artical_Name"));
artical.setArtical_Content(rs.getString("Artical_Content"));
artical.setArtical_Date(rs.getDate("Artical_Date"));
artical.setArtical_Glancenumber(rs.getInt("Artical_Glancenumber"));
artical.setUser_Id(rs.getInt("User_Id"));
artical.setArticalTypel_Id(rs.getInt("ArticalTypel_Id"));
artical.setArtical_Character(rs.getString("Artical_Character"));
model_artical.add(artical);
}
DB.closeConnection(con,stm,rs);
return model_artical;
}
/*
* @Description: 查询文章;
* @param :参数是typeid，start，end ,分别是文章的typeid值和数据的第几条数据，和一次查询的数量；
* @return:返回查询的记录，封装在List中。
* */
public List<Model_Artical> querytype(int typeid,int start,int end) throws Exception{
Connection con = DB.getConnection();
Statement stm = con.createStatement();
String sql="SELECT * FROM tbl_artical where ArticalTypel_Id = ‘"+typeid+"‘ limit "+start+","+end+"";
ResultSet rs= stm.executeQuery(sql);
List<Model_Artical> model_artical = new ArrayList<Model_Artical>();
Model_Artical artical= null;
while(rs.next()){
artical = new Model_Artical();
artical.setArtical_Id(rs.getInt(1));
artical.setArtical_Name(rs.getString("Artical_Name"));
artical.setArtical_Content(rs.getString("Artical_Content"));
artical.setArtical_Date(rs.getDate("Artical_Date"));
artical.setArtical_Glancenumber(rs.getInt("Artical_Glancenumber"));
artical.setUser_Id(rs.getInt("User_Id"));
artical.setArticalTypel_Id(rs.getInt("ArticalTypel_Id"));
artical.setArtical_Character(rs.getString("Artical_Character"));
model_artical.add(artical);
}
DB.closeConnection(con,stm,rs);
return model_artical;
}
/*创建用来实现查看文章详细内容的方法---queryArticleSingle()；
* 该方法带有一个参数。表示文章的id*
*/
public Model_Artical queryArticleSingle(int id) throws Exception{
String sql = "select * from tbl_artical where Artical_Id = ‘"+id+"‘";
Connection con = DB.getConnection();
Statement stm = con.createStatement();
ResultSet rs= stm.executeQuery(sql);
try{
while(rs.next()){
Model_Artical artical = new Model_Artical();
artical.setArtical_Id(rs.getInt(1));
artical.setArtical_Name(rs.getString("Artical_Name"));
artical.setArtical_Content(rs.getString("Artical_Content"));
artical.setArtical_Date(rs.getDate("Artical_Date"));
artical.setArtical_Glancenumber(rs.getInt("Artical_Glancenumber"));
artical.setUser_Id(rs.getInt("User_Id"));
artical.setArticalTypel_Id(rs.getInt("ArticalTypel_Id"));
DB.closeConnection(con,stm,rs);
return artical;
}
}catch(Exception e){
e.printStackTrace();
System.out.println("按文章类别查看文章失败");
DB.closeConnection(con,stm,rs);
return null;
}
return null;
}
/* operationArtical()方法 实现对数据库进行其他的更新操作,如添加，修改和删除*/
public boolean operattionArtical(String oper,Model_Artical artical) throws Exception{
Connection con = DB.getConnection();
Statement stm = con.createStatement();
String sql = null;
if(oper.equals("add")){
sql = "insert into tbl_artical (Artical_Name,Artical_Content,Artical_Date,Artical_Glancenumber,ArticalTypel_Id,User_Id,Artical_Character) values(‘"+artical.getArtical_Name()+"‘,‘"+artical.getArtical_Content()+"‘,‘"+new Date(artical.getArtical_Date().getTime())+"‘,‘"+artical.getArtical_Glancenumber()+"‘,‘"+artical.getArticalTypel_Id()+"‘,‘"+artical.getUser_Id()+"‘,‘"+artical.getArtical_Character()+"‘)";
int rs = stm.executeUpdate(sql);
DB.closeConnection(con,stm,null);
if( rs > 0 ){
return true;
}else{
return false;
}
}
return false;
}
/*创建一个方法是删除相应的文章*/
public boolean deleteartical(int articalId) throws Exception{
Connection con = DB.getConnection();
Statement stm = con.createStatement();
String sql="delete from tbl_artical where Artical_Id ="+articalId;
int rs = stm.executeUpdate(sql);
if( rs > 0 ){
DB.closeConnection(con,stm,null);
System.out.println("删除成功");
return true;
}else{
DB.closeConnection(con,stm,null);
System.out.println("删除失败");
return false;
}
}
/*创建一个修改相对应的文章*/
public boolean modifyarticle(int articleId,String articlecontent,String articlename,String character,int typeid) throws Exception{
Connection con = DB.getConnection();
Statement stm = con.createStatement();
String sql="UPDATE tbl_artical SET Artical_Content =‘"+articlecontent+"‘,Artical_Name=‘"+articlename+"‘,Artical_Character =‘"+character+"‘,ArticalTypel_Id="+typeid+" where Artical_Id ="+articleId;
int rs = stm.executeUpdate(sql);
if( rs > 0 ){
DB.closeConnection(con,stm,null);
System.out.println("修改成功");
return true;
}else{
DB.closeConnection(con,stm,null);
System.out.println("修改失败");
return false;
}
}
/*
* @Description: 计算某一类文章或者是全部文章的总数;
* @param :参数是typeid，判断是某一类文章，还是数据库里的全部文章，
* @return:返回数量；
* */
public int articalnum(int typeid) throws Exception{
String sql;
if(typeid > 0){
sql = "SELECT count(*) FROM tbl_artical where ArticalTypel_Id = ‘"+typeid+"‘";
}else{
sql="SELECT count(*) FROM tbl_artical";
}
Connection con = DB.getConnection();
Statement stm = con.createStatement();
ResultSet rs= stm.executeQuery(sql);
int i = 0;
while(rs.next()){
i = rs.getInt(1);
}
DB.closeConnection(con,stm,rs);
return i;
}
}