• jsp第六次作业


    USE test;
    CREATE TABLE lg(
    id INT(10),
    sname VARCHAR(10),
    spassword VARCHAR(10)
    );
    

      

    public class login {
        private int id;
        private String sname;
        private String spassword;
        public int getId() {
            return id;
        }
        public void setId(int id) {
            this.id = id;
        }
        public String getSname() {
            return sname;
        }
        public void setSname(String sname) {
            this.sname = sname;
        }
        public String getSpassword() {
            return spassword;
        }
        public void setSpassword(String spassword) {
            this.spassword = spassword;
        }
    }
    

      

    import java.sql.Statement;
    import java.sql.Connection;
    import java.sql.DriverManager;
    import java.sql.ResultSet;
    import java.sql.SQLException;
    
    
    public class JDBCUtils {
    //获取连接对象的方法
        public static Connection getCon() throws Exception{
            //1.加载数据库驱动
                    Class.forName("com.mysql.jdbc.Driver");
                    //2.通过DriverManager获取数据库连接
                    Connection con=DriverManager.getConnection("jdbc:mysql://localhost:3306/test", "root", "ROOT");
                    return con;
                    //3.通过Connection対象获取Statement対象                
        }
        
    //关闭连接,释放资源
        public static void realse(ResultSet rs,Statement stmt,Connection con){
            if(rs!=null){
                try{
                    rs.close();
                }catch (SQLException e){
                    //TODO Auto-generated catch block
                    e.printStackTrace();
                    }
                rs=null;
                }
            if(stmt!=null){
                try{
                    stmt.close();
                }catch (SQLException e){
                    //TODO Auto-generated catch block
                    e.printStackTrace();
                    }
                stmt=null;
                }
            if(con!=null){
                try{
                    con.close();
                }catch (SQLException e){
                    e.printStackTrace();
                    }
                con=null;
                }
        }
    }
    

      

    import java.sql.Connection;
    import java.sql.PreparedStatement;
    import java.sql.ResultSet;
    import java.sql.SQLException;
    import java.sql.Statement;
    import java.util.ArrayList;
    import java.util.List;
    
    /*
     完成对数据库的增删改查(crud操作)
     */
    public class Dao { 
        // 1.提供添加方法
        public boolean insert(login lg) {
            Connection con = null;
            Statement stmt = null;
            try {
    //1.获取连接对象
                con=JDBCUtils.getCon();
    //2.获取执行sql语句的对象
                stmt=con.createStatement();
    //3.执行sql语句(添加信息语句)
                String sql="insert into lg(id,sname,spassword)"+"values('"
                        +lg.getId()+"','"
                        +lg.getSname()+"','"
                        +lg.getSpassword()+"'"//user.getBirthDay()替换成sqlBirthDay
                        +")";
                int row = stmt.executeUpdate(sql);
                if(row>0){
                    //插入成功
                    return true;
                }
            } catch (Exception e) {
                throw new RuntimeException(e);
            } finally {
                JDBCUtils.realse(null, stmt, con);
            }
    
            return false;
    
        }
        
        
        //2.提供查询所有的方法
        public List<login>findAllUser(){
            Connection con= null;
            Statement stmt = null;
            ResultSet rs = null;
            try{
                //1.获取连接对象
                con = JDBCUtils.getCon();
                //2.获取执行sql语句的对象
                stmt = con.createStatement();
                //3.执行sql语句(查询语句)
                String sql ="select * from lg";
                rs = stmt.executeQuery(sql);
                //4.遍历rs
                List<login> list = new ArrayList<login>();
                while(rs.next()){
                    //一行数据对应一个对象,获取每一行的对象,就设置给一个user对象
                    login lg=new login();
                    lg.setId(rs.getInt("id"));
                    lg.setSname(rs.getString("sname"));
                    lg.setSpassword(rs.getString("spassword"));               
                    list.add(lg);                
                }
                return list;
                    
            }catch (Exception e) {
                throw new RuntimeException(e);
            } finally {
                JDBCUtils.realse(rs, stmt, con);
            }        
        //    return null;
        }
        
        
        
        //3.根据id,来查询记录
        public login findUserById(int id){
            Connection con= null;
            PreparedStatement stmt = null;
            ResultSet rs = null;
            try{
                //1.获取连接对象
                con = JDBCUtils.getCon();
                //2.获取执行sql语句的对象
                String sql ="select * from lg where id=?";
                stmt = con.prepareStatement(sql);
                //3.执行sql语句,给id赋值
                stmt.setInt(1, id);       
                rs = stmt.executeQuery();
                //4.遍历rs
                
                if(rs.next()){
                    //一行数据对应一个对象,获取每一行的对象,就设置给一个user对象
                     login lg=new login();
                     lg.setId(rs.getInt("id"));
                     lg.setSname(rs.getString("sname"));
                     lg.setSpassword(rs.getString("spassword"));  
                    
                    return lg;            
                }
                
            }catch (Exception e) {
                throw new RuntimeException(e);
            } finally {
                JDBCUtils.realse(rs, stmt, con);
            }        
            return null;            
        }
        
    
        
        //4.提供一个修改方法,根据id值修改记录
        public boolean update(login lg){
        Connection con = null;
        PreparedStatement stmt = null;
        try {
    //1.获取连接对象
            con=JDBCUtils.getCon();
    //2.获取执行sql语句的对象
            String sql="update lg set sname =?,spassword=? where id=?";
            stmt = con.prepareStatement(sql);//2.的sql语句*
    //3.执行sql语句(给占位符赋值)
            
            stmt.setString(1, lg.getSname());
            stmt.setString(2, lg.getSpassword());
            stmt.setInt(3, lg.getId());
                    
            int row = stmt.executeUpdate();//应该()里无sql,因为在2.里已经传了sql语句*
            if(row>0){
                //插入成功
                return true;
            }
        } catch (Exception e) {
            throw new RuntimeException(e);
        } finally {
            JDBCUtils.realse(null, stmt, con);
        }
        return false;
        }
        
        
        //5.删除方法
        public boolean delete (int id){
            Connection con = null;
            PreparedStatement stmt = null;
            try {
        //1.获取连接对象
                con=JDBCUtils.getCon();
        //2.获取执行sql语句的对象
                String sql="delete from lg where id=?";
                stmt = con.prepareStatement(sql);//2.的sql语句*
        //3.执行sql语句(给占位符赋值)
                
                stmt.setInt(1,id);
                        
                int row = stmt.executeUpdate();//应该()里无sql,因为在2.里已经传了sql语句*
                if(row>0){
                    //插入成功
                    return true;
                }
            } catch (Exception e) {
                throw new RuntimeException(e);
            } finally {
                JDBCUtils.realse(null, stmt, con);
            }
            return false;
            
        }
    }
    

      

    import java.sql.Connection;
    import java.sql.DriverManager;
    import java.sql.PreparedStatement;
    import java.sql.ResultSet;
    
    public class test {
        public static void main(String[] args) {
            // 测试1插入信息代码
            Dao dao = new Dao();
            login lg = new login();
            lg.setId(2);
            lg.setSname("zqb");
            lg.setSpassword("1111");
            boolean flag = dao.insert(lg);
            System.out.print(flag);
            // jdbc操作步骤
            // 注册学生信息
        }
    
    }
    

      

    import java.util.List;
    
    
    public class test2 {
    
         public static void main(String[] args){
                //测试2查询所有信息条数代码
                Dao dao= new Dao();
                List<login> list =dao.findAllUser();    
                System.out.println(list.size());
        }
    
    }
    

      

    public class test3 {
         public static void main(String[] args){
                //测试3查询id=?的名字代码
            Dao dao= new Dao();
            login lg = dao.findUserById(2);
            System.out.println(lg.getSname());
            }
    }
    

      

    public class test4 {
        public static void main(String[] args){
            //测试4修改信息代码
            Dao dao= new Dao();
            login lg=new login();
            lg.setId(2);
            lg.setSname("zqbb");
            lg.setSpassword("2222");      
            boolean flag = dao.update(lg);
            System.out.println(flag);
            //true则成功,否则不成功
    }
    }
    

      

    public class test5 {
        public static void main(String[] args){
            //测试5删除信息代码
            Dao dao= new Dao();
            boolean flag = dao.delete(2);
            System.out.println(flag);
        }
    }
    

     

     

     

     

     

     

     

     

     

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  • 原文地址:https://www.cnblogs.com/9428zzz/p/12756310.html
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