数据库MySQL
数据库MySQL-20175218
一、题目要求
- 下载附件中的world.sql.zip, 参考http://www.cnblogs.com/rocedu/p/6371315.html#SECDB,导入world.sql,提交导入成功截图
- 编写程序,查询世界上超过“你学号前边七位并把最后一位家到最高位,最高位为0时置1”(比如学号20165201,超过3016520;学号20165208,超过1016520)的所有城市列表,提交运行结果截图
- 编写程序,查询世界上的所有中东国家的总人口
- 编写程序,查询世界上的平均寿命最长和最短的国家
二、实验程序
1、getCity
package MySQL;
import java.sql.*;
public class getCity {
public static void main(String[] args) {
Connection con;
Statement sql;
ResultSet rs;
con = GetDBConnection.connectDB("world","root","");
if(con == null) {
return;
}
try {
sql=con.createStatement();
rs = sql.executeQuery("SELECT * FROM city");
while (rs.next()) {
int ID = rs.getInt(1);
String Name = rs.getString(2);
String CountryCode = rs.getString(3);
String District = rs.getString(4);
int Population =rs.getInt(5);
if(Population>1017520) {
System.out.printf("%d\t", ID);
System.out.printf("%s\t", Name);
System.out.printf("%s\t", CountryCode);
System.out.printf("%s\t", District);
System.out.printf("%d\n", Population);
}
}
con.close();
}
catch (SQLException e) {
System.out.println(e);
}
}
}
2、getPopulation
package MySQL;
import java.sql.*;
public class getPopulation {
public static void main(String[] args) {
Connection con;
Statement sql;
ResultSet rs;
con = GetDBConnection.connectDB("world","root","");
if(con == null) {
return;
}
String sqlStr = "select * from country where Region = 'Middle East'";
try {
sql = con.createStatement();
rs = sql.executeQuery(sqlStr);
long totalpopulation = 0;
while(rs.next()) {
int Population = rs.getInt(7);
totalpopulation +=Population;
}
System.out.println("中东国家的总人口为"+totalpopulation);
con.close();
}
catch (SQLException e) {
System.out.println(e);
}
}
}
3、getlife
package MySQL;
import java.sql.*;
public class getlife {
public static void main(String[] args) {
Connection con;
Statement sql;
ResultSet rs;
con = GetDBConnection.connectDB("world","root","");
if(con == null) {
return;
}
String sqlStr = "select * from country order by LifeExpectancy";
try {
sql = con.createStatement();
rs = sql.executeQuery(sqlStr);
rs.first();
String highcountry,lowcountry;
float number1 = rs.getInt(8);
while(number1 == 0) {
rs.next();
number1 = rs.getInt(8);
}
lowcountry = rs.getString(2);
System.out.println("世界上平均寿命最短的国家为:"+lowcountry+" 寿命为"+number1);
rs.last();
float number2 = rs.getInt(8);
highcountry = rs.getString(2);
System.out.println("世界上平均寿命最长的国家为:"+highcountry+" 寿命为"+number2);
con.close();
}
catch (SQLException e) {
System.out.println(e);
}
}
}
4、GetDBConnection
package MySQL;
import java.sql.*;
public class GetDBConnection {
public static Connection connectDB(String DBName,String id,String p) {
Connection con = null;
String
uri = "jdbc:mysql://localhost:3306/"+DBName+"?serverTimezone=GMT%2B8&characterEncoding=utf-8";
try{ Class.forName("com.mysql.cj.jdbc.Driver");//加载JDBC-MySQL驱动
}
catch(Exception e){}
try{
con = DriverManager.getConnection(uri,id,p); //连接代码
}
catch(SQLException e){}
return con;
}
}
三、实验截图
四、代码托管
码云链接(https://gitee.com/cjy-123/20175218cjy/tree/master/week10/mysql)