首先说明，由于是8版本的数据库，所以配置类的写法上与5版本的有所区别，需要注意，同时用idea或eclipse时需要导入jar包
如果想要下载8版本不同的jar包只需要修改8.0.28为指定版本即可。
idea导入jar包的方法如下：
然后是代码部分，首先先建表：
CREATE TABLE `train_message` ( `id` int NOT NULL AUTO_INCREMENT COMMENT '主键id', `train_name` varchar(20) NOT NULL COMMENT '列车名', `origin` varchar(30) NOT NULL COMMENT '始发地', `terminal` varchar(30) NOT NULL COMMENT '终到地', `departure_time` timestamp NOT NULL COMMENT '出站时间', `state` varchar(10) CHARACTER SET utf8 COLLATE utf8_general_ci NOT NULL DEFAULT '正常' COMMENT '列车状态', PRIMARY KEY (`id`) ) ENGINE=InnoDB AUTO_INCREMENT=9 DEFAULT CHARSET=utf8mb3
然后创建连接的配置类DbConfig.java，localhost是本机的ip地址，如果有服务器就填服务器的ip地址，message是数据库的名字，这里一张图说下有很多新手误解的名字
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
/**
* 数据库配置类
* @author 景苒
*/
public class DbConfig {
public Connection dbConfig() throws SQLException {
try {
Class.forName("com.mysql.cj.jdbc.Driver");
}catch (Exception e) {
System.out.print("加载驱动失败!");
e.printStackTrace();
}
String url = "jdbc:mysql://localhost:3306/message?useSSL=false&useUnicode=true&characterEncoding=utf-8&serverTimezone=GMT%2B8&allowPublicKeyRetrieval=true";
String user = "root";
String password = "123456";
return DriverManager.getConnection(url, user, password);
}
}然后写下主函数Main.java，这里主函数的函数体可以在最后再写，需要什么功能就把注释打开就好，快捷注释的方法，选中这句话，按ctrl加/，就能全注释了。
import java.sql.SQLException;
/**
* 主函数，调用功能
* @author 景苒
*/
public class Main {
public static void main(String[] args) throws SQLException {
// new GetMessage().getMessage();
// new UpdateTrainState().updateTrainState();
// new InsertTrain().insertTrain();
// new GetNumber().getNumber();
}
}然后是每个的功能：
建GetMessage.java类
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
/**
* 查询沈阳到武汉的所有列车信息，按出发时间先后排序
* @author 景苒
*/
public class GetMessage {
public void getMessage() throws SQLException {
Connection con = new DbConfig().dbConfig();
String sql = "select * from `train_message` where origin = ? and terminal = ? ORDER BY departure_time ASC";
String origin = "沈阳";
String terminal = "武汉";
PreparedStatement ps = con.prepareStatement(sql);
ps.setString(1, origin);
ps.setString(2, terminal);
ResultSet rs = ps.executeQuery();
try {
while (rs.next()) {
System.out.println("列车名：" + rs.getString("train_name")
+ " 始发站：" + rs.getString("origin")
+ " 终到站：" + rs.getString("terminal")
+ " 出发时间：" + rs.getString("departure_time")
+ " 列车状态：" + rs.getString("state"));
}
}catch (SQLException e) {
e.printStackTrace();
}finally {
ps.close();
con.close();
}
}
}建UpdateTrainState.java类
import java.sql.Connection;
import java.sql.SQLException;
import java.sql.Statement;
/**
* 修改T2255列车的状态为停运
* @author 景苒
*/
public class UpdateTrainState {
public void updateTrainState() throws SQLException {
Connection con = new DbConfig().dbConfig();
String sql = "UPDATE `train_message` SET state = '停运' WHERE train_name = 'T2255'";
Statement statement = con.createStatement();
try {
int i = statement.executeUpdate(sql);
if (i > 0) {
System.out.println("更新成功");
}else {
System.out.println("更新失败");
}
}catch (SQLException e) {
e.printStackTrace();
}finally {
statement.close();
con.close();
}
}
}建InsertTrain.java类
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.SQLException;
import java.util.Scanner;
/**
* 新增一辆列车信息（自己输入）
* 始发时间为timestamp类型，输入时需要确保格式正确，如：2019-01-01 00:00:00
* @author 景苒
*/
public class InsertTrain {
public void insertTrain() throws SQLException {
Connection con = new DbConfig().dbConfig();
Scanner scanner = new Scanner(System.in);
String sql = "insert into `train_message` values(null, ?, ?, ?, ?, default)";
System.out.print("请输入列车名：");
String trainName = scanner.nextLine();
System.out.print("请输入始发站：");
String origin = scanner.nextLine();
System.out.print("请输入终到站：");
String terminal = scanner.nextLine();
System.out.print("请输入始发时间：");
String departureTime = scanner.nextLine();
PreparedStatement ps = con.prepareStatement(sql);
ps.setString(1, trainName);
ps.setString(2, origin);
ps.setString(3, terminal);
ps.setString(4, departureTime);
try {
int i = ps.executeUpdate();
if (i > 0) {
System.out.println("添加成功");
}else {
System.out.println("添加失败");
}
}catch (SQLException e) {
e.printStackTrace();
}finally {
ps.close();
con.close();
}
}
}建GetNumber.java类
import java.sql.Statement;
/**
* 查询状态为正常的列车数量
* @author 景苒
*/
public class GetNumber {
public void getNumber() throws SQLException {
Connection con = new DbConfig().dbConfig();
String sql = "select count(state) from `train_message` where state = '正常'";
Statement statement = con.createStatement();
try {
ResultSet resultSet = statement.executeQuery(sql);
while (resultSet.next()) {
System.out.println("状态为正常的列车数量为：" + resultSet.getInt(1));
}
}catch (SQLException e){
e.printStackTrace();
}finally {
statement.close();
con.close();
}
}
}最后附上navicat的属性结构图和样例插入的语句
