实验一(jdbc连接数据库）
第一步 打开mysql第二步创建工程并添加导包
教程：https://jingyan.baidu.com/article/3aed632e1a4ceb70108091f6.html第三步，编写代码：主操作类：
import java.sql.DriverManager;
import java.sql.ResultSet;
import com.mysql.jdbc.Connection;
import com.mysql.jdbc.Statement;
public class JdbcDemo {
public static void main(String[] args) {
ResultSet result = null;
Statement statement = null;
try {
Class.forName("com.mysql.jdbc.Driver"); //加载jdbc驱动
String url = "jdbc:mysql://localhost:3306/mysql?useUnicode" //地址
+ "=true&characterEncoding=utf-8&useSSL=false";
String username = "root"; //用户名
String password = "tyz19960912"; //密码
Connection connection = (Connection) DriverManager.getConnection(url,username,password);
statement = (Statement) connection.createStatement(); //连接实例
/*创建*/
JdbcCreate jdb1=new JdbcCreate();
jdb1.op(statement,result);
System.out.println(" 第一次操作： 数据表创建成功！打印数据");
JdbcSelect jdb5=new JdbcSelect();
jdb5.op(statement,result);
System.out.println(" ");
/*插入数据*/
Jdbcinsert_1 jdb2=new Jdbcinsert_1();
jdb2.op(statement,result);
System.out.println(" 第二次操作： users,person 插入数据成功！打印数据");
JdbcSelect jdb3=new JdbcSelect();
jdb3.op(statement,result);
System.out.println(" ");
/*插入数据*/
Jdbclnsert jdb31=new Jdbclnsert();
jdb31.op(statement,result);
System.out.println(" 第三次操作： users,person 插入数据成功！打印数据");
JdbcSelect jdb4=new JdbcSelect();
jdb4.op(statement,result);
System.out.println(" ");
/*插入数据*/
JdbcDrop jdb51=new JdbcDrop();
jdb51.op(statement,result);
System.out.println(" 第四次操作： 删除数据成功！打印数据");
JdbcSelect jdb41=new JdbcSelect();
jdb41.op(statement,result);
System.out.println(" ");
String query = "drop table users,person";//删除
statement.executeUpdate(query);
System.out.println(" 删除整个数据库,任务完成！！！");
}
catch (Exception e) {
System.out.println(e.getMessage());
}
}
} 创建操作
import java.sql.ResultSet;
import java.sql.SQLException;
import com.mysql.jdbc.Statement;
public class JdbcCreate { //创建函数
public void op (Statement statement, ResultSet result) throws SQLException {
String sql = "CREATE TABLE users"
+ "("
+ " username varchar(10) not null,"
+ " pass varchar(8) not null,"
+ " PRIMARY KEY ( username )"
+ ")";
statement.executeUpdate(sql);
sql = "CREATE TABLE person"
+ "("
+ " username varchar(10) not null,"
+ " name varchar(20) not null,"
+ " age int default 18 ,"
+ " teleno char(11) default '18877009966' ,"
+ " PRIMARY KEY ( name )"
+ ")";
statement.executeUpdate(sql);
}
}
第一次插入操作
import java.sql.ResultSet;
import java.sql.SQLException;
import com.mysql.jdbc.Statement;
public class Jdbcinsert_1 {
public void op (Statement statement, ResultSet result) throws SQLException {
String []sql= {"insert into users(username,pass) values('ly','123456')",
"insert into users(username,pass) values('liming','345678')",
"insert into users(username,pass) values('test','11111')",
"insert into users(username,pass) values('test1','12345')",
"insert into person(username,name) values('ly','雷力')",
"insert into person(username,name,age) values('liming','李明',25)",
"insert into person(username,name,age,teleno) values('test','测试用户',20,'13388449933')"};
for(int x=0;x<7;x++) {
statement.executeUpdate(sql[x]);
}
}
}
第二次插入操作：
import java.sql.ResultSet;
import java.sql.SQLException;
import com.mysql.jdbc.Statement;
public class Jdbclnsert {
public void op (Statement statement, ResultSet result) throws SQLException {
String []s0 = {"ly", "test2", "test1", "test", "admin" }; //username
String []s1 = {"88888"};
String []s2 = {"王五","测试用户2","测试用户1","张三","admin"}; //name
String []s3 = {"0", "2", "33","23", "0"}; //age
String []s4 = {"NULL", "NULL", "NULL", "18877009966","NULL"}; //TELENO
for(int i=0;i<5;i++){
String sql;
String query = "SELECT * FROM person where username='"+s0[i]+"'";
result = statement.executeQuery(query);
String temp =s0[i];
String temp1=s1[0];
String temp2=s2[i];
String temp3=s3[i];
String temp4=s4[i];
if(!result.next()) {
if(i!=2) {
sql="insert into users(username,pass) values('"+temp+"','"+temp1+"')";
statement.executeUpdate(sql);
}
sql="insert into person(username,name) values('"+temp+"','"+temp2+"')";
statement.executeUpdate(sql);
}
else {
sql="update person set name='"+temp2+"' where username='\"+temp+\"'";
sql="update person set pass='\"+temp1+\"' where username='\"+temp+\"'";
sql="update person set age='"+temp3+"' where username='\"+temp+\"'";
sql="update person set teleno='"+temp4+"' where username='\"+temp+\"'";
statement.executeUpdate(sql);
}
}
}
}
删除操作
import java.sql.ResultSet;
import java.sql.SQLException;
import com.mysql.jdbc.Statement;
public class JdbcDrop { //删除函数
public void op (Statement statement, ResultSet result) throws SQLException {
String query = "delete from users where username like 'test%'";//删除
statement.executeUpdate(query);
query = "delete from person where username like 'test%'";//删除
statement.executeUpdate(query);
}
}
查询函数
import java.sql.ResultSet;
import java.sql.SQLException;
import com.mysql.jdbc.Statement;
public class JdbcSelect { //查询函数
public void op (Statement statement, ResultSet result) throws SQLException{
String query = "SELECT * FROM users";
System.out.println("表users:");
System.out.println("+*************************************************************************+");
System.out.println("|字段名 username 字段名 pass |");
System.out.println("+-------------------------------------------------------------------------+");
result = statement.executeQuery(query);
while(result.next()) {
String s1 = result.getString(1);
String s2 = result.getString(2);
while(s1.length()<20) {
s1+=' ';
}
System.out.println("| "+s1+" "+s2+"");
System.out.println("+-------------------------------------------------------------------------+");
}
// System.out.println("+-------------------------------------------------------------------------+");
query = "SELECT * FROM person";
System.out.println("表person:");
System.out.println("+*************************************************************************+");
System.out.println("|字段名 username 字段名 name 字段名age 字段名 teleno|");
System.out.println("+-------------------------------------------------------------------------+");
result = statement.executeQuery(query);
while(result.next()) {
String s1 = result.getString(1);
String s2 = result.getString(2);
String s3 = result.getString(3) ;
String s4 = result.getString(4);
while(s1.length()<16) s1+=' ';
while(s2.length()<20) s2+=' ';
while(s3.length()<16) s3+=' ';
System.out.println("| "+s1+" "+s2+" "+s3+" "+s4);
System.out.println("+-------------------------------------------------------------------------+");
}
// System.out.println("+-------------------------------------------------------------------------+");
}
}运行效果：
第一次操作： 数据表创建成功！打印数据
表users:
+*************************************************************************+
|字段名 username 字段名 pass |
+-------------------------------------------------------------------------+
表person:
+*************************************************************************+
|字段名 username 字段名 name 字段名age 字段名 teleno |
+-------------------------------------------------------------------------+ 第二次操作： users,person 插入数据成功！打印数据
表users:
+*************************************************************************+
|字段名 username 字段名 pass |
+-------------------------------------------------------------------------+
| liming 345678
+-------------------------------------------------------------------------+
| ly 123456
+-------------------------------------------------------------------------+
| test 11111
+-------------------------------------------------------------------------+
| test1 12345
+-------------------------------------------------------------------------+
表person:
+*************************************************************************+
|字段名 username 字段名 name 字段名age 字段名 teleno |
+-------------------------------------------------------------------------+
| liming 李明 25 18877009966
+-------------------------------------------------------------------------+
| test 测试用户 20 13388449933
+-------------------------------------------------------------------------+
| ly 雷力 18 18877009966
+-------------------------------------------------------------------------+ 第三次操作： users,person 插入数据成功！打印数据
表users:
+*************************************************************************+
|字段名 username 字段名 pass |
+-------------------------------------------------------------------------+
| admin 88888
+-------------------------------------------------------------------------+
| liming 345678
+-------------------------------------------------------------------------+
| ly 123456
+-------------------------------------------------------------------------+
| test 11111
+-------------------------------------------------------------------------+
| test1 12345
+-------------------------------------------------------------------------+
| test2 88888
+-------------------------------------------------------------------------+
表person:
+*************************************************************************+
|字段名 username 字段名 name 字段名age 字段名 teleno |
+-------------------------------------------------------------------------+
| admin admin 18 18877009966
+-------------------------------------------------------------------------+
| liming 李明 25 18877009966
+-------------------------------------------------------------------------+
| test 测试用户 20 13388449933
+-------------------------------------------------------------------------+
| test1 测试用户1 18 18877009966
+-------------------------------------------------------------------------+
| test2 测试用户2 18 18877009966
+-------------------------------------------------------------------------+
| ly 雷力 18 18877009966
+-------------------------------------------------------------------------+ 第四次操作： 删除数据成功！打印数据
表users:
+*************************************************************************+
|字段名 username 字段名 pass |
+-------------------------------------------------------------------------+
| admin 88888
+-------------------------------------------------------------------------+
| liming 345678
+-------------------------------------------------------------------------+
| ly 123456
+-------------------------------------------------------------------------+
表person:
+*************************************************************************+
|字段名 username 字段名 name 字段名age 字段名 teleno |
+-------------------------------------------------------------------------+
| admin admin 18 18877009966
+-------------------------------------------------------------------------+
| liming 李明 25 18877009966
+-------------------------------------------------------------------------+
| ly 雷力 18 18877009966
+-------------------------------------------------------------------------+
删除整个数据库,任务完成！！！