跟汤老师学Java笔记：练习：学生管理系统
跟汤老师学Java笔记：练习：学生管理系统
完成：第一遍
1.练习：学生管理系统
主要功能：
(1).查询所有学生
(2).根据学号查询学生
(3).根据姓名和年龄范围查询学生，模糊查询
(4).添加学生
(5).修改学生
(6)根据学号删除学生
JdbcUtil工具类：
package sms;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
/**
* JDBC工具类
*/
public class JdbcUtil {
/**
* 获取数据库连接
*/
public static Connection getConnection() {
String driverClassName = "com.mysql.jdbc.Driver";
String url = "jdbc:mysql://localhost:3306/test?useUnicode=true&characterEncoding=utf8&rewriteBatchedStatements=true";
String username = "root";
String password = "123456";
Connection conn = null;
try {
Class.forName(driverClassName);
conn = DriverManager.getConnection(url, username, password);
} catch (ClassNotFoundException e) {
e.printStackTrace();
} catch (SQLException e) {
e.printStackTrace();
}
return conn;
}
/**
* 关闭资源
*/
public static void close(Connection conn, Statement stmt, ResultSet rs) {
if (rs != null) {
try {
rs.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
if (stmt != null) {
try {
stmt.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
if (conn != null) {
try {
conn.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
}
public static void close(Connection conn, Statement stmt) {
close(conn, stmt, null);
}
}
Student 类：
package sms;
import java.io.Serializable;
import java.util.Date;
/*
* 学生类
*/
public class Student implements Serializable {
private static final long serialVersionUID = -5984449679344766226L;
private Integer id;
private String name;
private Integer age;
private Double height;
//import java.util.Date
private Date bithday;
private Clazz clazz; // 所在班级
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public Integer getAge() {
return age;
}
public void setAge(Integer age) {
this.age = age;
}
public Double getHeight() {
return height;
}
public void setHeight(Double height) {
this.height = height;
}
public Date getBithday() {
return bithday;
}
public void setBithday(Date bithday) {
this.bithday = bithday;
}
public Clazz getClazz() {
return clazz;
}
public void setClazz(Clazz clazz) {
this.clazz = clazz;
}
@Override
public String toString() {
return "Student [id=" + id + ", name=" + name + ", age=" + age
+ ", height=" + height + ", bithday=" + bithday + ", clazz="
+ clazz + "]\n";
}
}
Clazz类：
package sms;
import java.io.Serializable;
/*
* 班级类
*/
public class Clazz implements Serializable {
private static final long serialVersionUID = 4262995174037152678L;
private Integer id;
private String name;
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
@Override
public String toString() {
return "Clazz [id=" + id + ", name=" + name + "]";
}
}
StudentTemplate 类：
package sms;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;
public class StudentTemplate {
Connection conn=null;
PreparedStatement ps=null;
ResultSet rs=null;
/**
* 查询操作
*/
public List<Student> query(String sql,Object... params){
List<Student> list=new ArrayList<Student>();
try {
conn=JdbcUtil.getConnection();
ps=conn.prepareStatement(sql);
//问号有几个参数，数组就有几个值
for (int i = 0; i < params.length; i++) {
ps.setObject(i+1, params[i]);
}
rs=ps.executeQuery();
while(rs.next()){
Student stu = new Student();
stu.setId(rs.getInt("id"));
stu.setName(rs.getString("name"));
stu.setAge(rs.getInt("age"));
stu.setHeight(rs.getDouble("height"));
// getDate()返回的是java.sql.Date
// sql.Date会自动转换成util.Date
stu.setBithday(rs.getDate("birthday"));
Clazz clazz = new Clazz();
clazz.setId(rs.getInt("cid"));
clazz.setName(rs.getString("cname"));
stu.setClazz(clazz);
list.add(stu);
}
} catch (SQLException e) {
e.printStackTrace();
}finally{
JdbcUtil.close(conn, ps, rs);
}
return list;
}
/**
* 更新操作
*/
public void update(String sql,Object... params){
try {
conn=JdbcUtil.getConnection();
ps=conn.prepareStatement(sql);
for (int i = 0; i < params.length; i++) {
ps.setObject(i+1,params[i]);
}
ps.executeUpdate();
} catch (SQLException e) {
e.printStackTrace();
}finally{
JdbcUtil.close(conn, ps, rs);
}
}
}
Test 类：
package sms;
import java.util.Date;
import java.util.List;
public class Test {
static StudentTemplate template=new StudentTemplate();
public static void main(String[] args) {
System.out.println(selectAll());
System.out.println(selectById(2));
System.out.println(selectByCondition("三", 10, 29));
Student stu = new Student();
stu.setId(4);
stu.setName("周杰伦 ");
stu.setAge(28);
stu.setHeight(170.5);
stu.setBithday(new Date());
Clazz clazz = new Clazz();
clazz.setId(1);
stu.setClazz(clazz);
// insert(stu);
update(stu);
deleteById(1);
System.out.println("success");
}
// 1.查询所有学生
public static List<Student> selectAll(){
String sql=new StringBuffer()
.append(" select ")
.append(" s.id,s.name,s.age,s.height,s.birthday,c.id cid,c.name cname ")
.append(" from ")
.append(" t_student s,t_class c")
.append(" where ")
.append(" s.cid=c.id ")
.toString();
return template.query(sql);
}
// 2.根据学号查询学生
public static Student selectById(int id){
String sql=new StringBuffer()
.append(" select ")
.append(" s.id,s.name,s.age,s.height,s.birthday,c.id cid,c.name cname ")
.append(" from ")
.append(" t_student s,t_class c")
.append(" where ")
.append(" s.cid=c.id and s.id=?")
.toString();
List<Student> list = template.query(sql, id);
return list.isEmpty()?null:list.get(0);
}
// 3.根据姓名和年龄范围查询学生
public static List<Student> selectByCondition(String name,int minAge,int maxAge){
String sql=new StringBuffer()
.append(" select ")
.append(" s.id,s.name,s.age,s.height,s.birthday,c.id cid,c.name cname ")
.append(" from ")
.append(" t_student s,t_class c")
.append(" where ")
.append(" s.cid=c.id and s.name like ? and s.age between ? and ?")
.toString();
return template.query(sql, "%"+name+"%",minAge,maxAge);
}
// 4.添加学生
public static void insert(Student stu){
String sql=new StringBuffer()
.append(" insert into ")
.append(" t_student ")
.append(" (name,age,height,birthday,cid) ")
.append(" values ")
.append(" (?,?,?,?,?) ")
.toString();
template.update(sql, stu.getName(),stu.getAge(),stu.getHeight(),stu.getBithday(),stu.getClazz().getId());
}
// 5.修改学生
public static void update(Student stu){
String sql=new StringBuffer()
.append(" update ")
.append(" t_student ")
.append(" set ")
.append(" name=?,age=?,height=?,birthday=?")
.append(" where ")
.append(" id=? ")
.toString();
template.update(sql, stu.getName(),stu.getAge(),stu.getHeight(),stu.getBithday(),stu.getId());
}
// 6.根据学号删除学生
public static void deleteById(int id){
String sql=new StringBuffer()
.append(" delete from ")
.append(" t_student ")
.append(" where ")
.append(" id=? ")
.toString();
template.update(sql, id);
}
}
sql语句：
create table t_class
(
id int auto_increment primary key,
name varchar(200)
)charset utf8;
create table t_student
(
id int auto_increment primary key,
name varchar(50) not null unique,
age int,
height double,
birthday date,
cid int,
foreign key(cid) references t_class(id)
)charset utf8;
insert into t_class (name) values("Java一班");
insert into t_class (name) values("Java二班");
insert into t_class (name) values("Python一班");
insert into t_class (name) values("Python二班");
insert into t_student() values(null,'汤小洋',20,180.5,'1990-12-4',1);
insert into t_student() values(null,'唐伯虎',25,173.5,curdate(),3);
insert into t_student() values(null,'张三',27,177,'1992-10-14',2);