利用JDBC对数据库进行简单的操作

通过JDBC对数据库进行简单的操作

bean类

package com.bdqn.entity;

import java.io.Serializable;

public class Student implements Serializable{
private int sid;
private String sname;
private int sage;
private String sdesc;

public Student() {
}

public Student(int sid, String sname, int sage, String sdesc) {
this.sid = sid;
this.sname = sname;
this.sage = sage;
this.sdesc = sdesc;
}

public int getSid() {
return sid;
}

public void setSid(int sid) {
this.sid = sid;
}

public String getSname() {
return sname;
}

public void setSname(String sname) {
this.sname = sname;
}

public int getSage() {
return sage;
}

public void setSage(int sage) {
this.sage = sage;
}

public String getSdesc() {
return sdesc;
}

public void setSdesc(String sdesc) {
this.sdesc = sdesc;
}

@Override
public String toString() {
return "Student [sid=" + sid + ", sname=" + sname + ", sage=" + sage
+ ", sdesc=" + sdesc + "]";
}

}

baseDao类

package com.bdqn.dao1;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.List;

import com.bdqn.entity.Student;
import com.bdqn.utils.JdbcUtils;

public class BaseDao {
private static Connection conn=null;
//获取连接
public static Connection getConnection(){
try {
Class.forName(JdbcUtils.driver);
conn=DriverManager.getConnection(JdbcUtils.url, JdbcUtils.user, JdbcUtils.pwd);
} catch (ClassNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}

return conn;
}
//关闭资源
public static void close(Connection conn,Statement sta,ResultSet rs){
try {
if (rs!=null) {
rs.close();
}
if (sta!=null) {
sta.close();
}
if (conn!=null) {
conn.close();
}
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
//增删改
public static int update(String sql,Object [] objects){
int num = 0;
PreparedStatement ps=null;
try {
conn=getConnection();
ps=conn.prepareStatement(sql);
if (objects!=null && objects.length>0) {
for (int i = 0; i < objects.length; i++) {
ps.setObject((i+1), objects[i]);
}
}
num=ps.executeUpdate();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return num;

}
//查询
public static ResultSet getResultSet(String sql,Object [] objects){
PreparedStatement ps=null;
ResultSet rs=null;
try {
conn=getConnection();
ps=conn.prepareStatement(sql);
if (objects!=null && objects.length>0) {
for (int i = 0; i < objects.length; i++) {
ps.setObject((i+1), objects[i]);
}
}
rs=ps.executeQuery();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return rs;
}

}

dao类

package com.bdqn.dao1;

import java.util.List;

import com.bdqn.entity.Student;

public interface StudentDao {
public int insert(Student stu);//增加
public int delete(int sid);//删除
public int update(Student stu);//修改
public List<Student> selectAllStudents();//全部查询
public List<Student> selectStudents(int sid);//单个查询
}

daoimpl类

package com.bdqn.dao.impl;

import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;

import com.bdqn.dao1.BaseDao;
import com.bdqn.dao1.StudentDao;
import com.bdqn.entity.Student;

public class StudentImpl extends BaseDao implements StudentDao{

//增
@Override
public int insert(Student stu) {
String insertSql="insert into student values(?,?,?,?)";
Object [] objects={stu.getSid(),stu.getSname(),stu.getSage(),stu.getSdesc()};
int num=this.update(insertSql, objects);
return num;
}
//删
@Override
public int delete(int sid) {
String deleteSql="delete from student where sid=?";
Object [] objects={sid};
int num=this.update(deleteSql, objects);
return num;
}
//改
@Override
public int update(Student stu) {
String updateSql="update student set sname=?";
Object [] objects={stu.getSname()};
int num=this.update(updateSql, objects);
return num;
}
//全查询
@Override
public List<Student> selectAllStudents() {
String sql = "select * from student";
List<Student> list=null;
try {
ResultSet rs=this.getResultSet(sql, null);
list=new ArrayList<Student>();
while (rs.next()) {
Student stu=new Student();

int id=rs.getInt("sid");
String name=rs.getString("sname");
int age=rs.getInt("sage");
String desc=rs.getString("sdesc");

stu.setSid(id);
stu.setSname(name);
stu.setSage(age);
stu.setSdesc(desc);

list.add(stu);
}
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTr
b5a5
ace();
}
return list;
}
//根据ID进行查询
@Override
public List<Student> selectStudents(int sid) {
String sql = "select * from student where sid=?";
List<Student> list=null;
try {
ResultSet rs=this.getResultSet(sql, null);
list=new ArrayList<Student>();
while (rs.next()) {
Student stu=new Student();

int id=rs.getInt("sid");
String name=rs.getString("sname");
int age=rs.getInt("sage");
String desc=rs.getString("sdesc");

stu.setSid(id);
stu.setSname(name);
stu.setSage(age);
stu.setSdesc(desc);

list.add(stu);
}
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return list;
}

}

util类

package com.bdqn.utils;

public class JdbcUtils {
public static final String driver="com.mysql.jdbc.Driver";
public static final String url="jdbc:mysql://localhost:3306/student";
public static final String user="root";
public static final String pwd="root";

}

测试类

package com.bdqn.test;

import java.util.List;

import com.bdqn.dao.impl.StudentImpl;
import com.bdqn.dao1.StudentDao;
import com.bdqn.entity.Student;

public class Test {
public static void main(String[] args) {
StudentDao dao=new StudentImpl();
/**
* 增加
*/
/*Student stu=new Student();
int num=dao.insert(stu);
System.out.println(num);*/
/**
* 删除（根据sid）
*/
/*Student stu=new Student();
dao.delete(0);*/
/**
* 修改名字
*/
/*Student stu=new Student();
int num=dao.update(stu);
System.out.println(num);*/
/**
* 全查
*/
List<Student> list=dao.selectAllStudents();
for(Student stu : list){
System.out.println(stu.toString());
}
}

}

脚注

目录

[TOC]