package ShuJuKu ;
import java. sql. * ;
import java. util. HashMap ;
public class sjk_cz {
public static void main ( String [ ] args) throws SQLException , ClassNotFoundException {
HashMap < String , Object > map = new HashMap < > ( ) ;
Class . forName ( "com.mysql.cj.jdbc.Driver" ) ;
String url = "jdbc:mysql://339.196.102.504:3306/hx?serverTimezone=UTC&useSSL" +
"=false&allowPublicKeyRetrieval=true&serverTimezone=GMT%2b8" ;
String user = "root" ;
String psw = "123456" ;
Connection connection = DriverManager . getConnection ( url, user, password) ;
Statement statement = connection. createStatement ( ) ;
String sql = "select * from user where phone = '15199235042'" ;
ResultSet resultSet = statement. executeQuery ( sql) ;
int count = resultSet. getMetaData ( ) . getColumnCount ( ) ;
while ( resultSet. next ( ) ) {
String field = resultSet. getMetaData ( ) . getColumnName ( 1 ) ;
String field1 = ( String ) resultSet. getObject ( field) ;
for ( int i = 1 ; i <= count; i++ ) {
String field2 = resultSet. getMetaData ( ) . getColumnName ( i) ;
String field3 = ( String ) resultSet. getObject ( field2) ;
map. put ( field2, resultSet. getString ( field2) ) ;
map. put ( "phone" , resultSet. getString ( "phone" ) ) ;
String phone1 = ( String ) map. get ( "phone" ) ;
System . out. println ( phone1) ;
}
}
String sql = "INSERT INTO user(phone, pwd, mibao, jijiu) VALUES('123', '123', '123', '123');" ;
int number = statement. executeUpdate ( sql) ;
resultSet. close ( ) ;
statement. close ( ) ;
connection. close ( ) ;
}
}
增删查改sql语句
CREATE DATABASE student
DROP DATABASE student
CREATE TABLE stuMess(
sid INT ,
sname VARCHAR ( 20 ) ,
sage INT ,
ssex CHAR ( 4 ) )
INSERT INTO stumess VALUES ( 1 , 'cuihua' , 18 , '女' )
INSERT INTO stumess VALUES ( 2 , '老高' , 20 , '男' )
UPDATE stumess SET ssex= '女' , sage= 73 WHERE sid= 2
DELETE from stumess
TRUNCATE TABLE stumess
SELECT * FROM stumess
SELECT sname, ssex from stumess
SELECT sname, sexx FROM stumess WHERE sid= 1
查询( select )
插入( insert )
修改( update )
删除( delete )
grant select on stumess root;
revoke select on stumess from public ;
数据库语句封装
import java. sql . * ;
public class connectionMysql {
Connection con = null ;
Statement sta = null ;
ResultSet res = null ;
public Connection openMysql( ) {
try {
String username = "root" ;
String pwd = "123456" ;
String url = "jdbc:mysql://localhost:3306/student?serverTimezone=UTC&useSSL" +
"=false&allowPublicKeyRetrieval=true&serverTimezone=GMT%2b8" ;
Class. forName( "com.mysql.cj.jdbc.Driver" ) ;
con = DriverManager. getConnection( url, username, pwd) ;
} catch ( Exception e) {
System. out . println( "------------------连接异常------------------" ) ;
e. printStackTrace( ) ;
System. out . println( "------------------连接异常------------------" ) ;
}
return con;
}
public int update ( String sql ) {
int re = 0 ;
try {
sta = con. createStatement( ) ;
re = sta. executeUpdate( sql ) ;
} catch ( SQLException e) {
System. out . println( "------------------操作异常------------------" ) ;
e. printStackTrace( ) ;
System. out . println( "------------------操作异常------------------" ) ;
}
return re;
}
public ResultSet select ( String sql ) {
try {
sta = con. createStatement( ) ;
res = sta. executeQuery( sql ) ;
} catch ( SQLException e) {
System. out . println( "------------------查询异常------------------" ) ;
e. printStackTrace( ) ;
System. out . println( "------------------查询异常------------------" ) ;
}
return res;
}
public void showTableMessage( String tableName) {
try {
String sql = "select * from " + tableName;
sta = con. createStatement( ) ;
res = sta. executeQuery( sql ) ;
ResultSetMetaData meta = res. getMetaData( ) ;
int count = meta. getColumnCount( ) ;
for ( int i = 1 ; i <= count; i+ + ) {
String columnName = meta. getColumnName( i) ;
int columnType = meta. getColumnType( i) ;
String columnTypeName = meta. getColumnTypeName( i) ;
System. out . println( columnName+ ":" + columnTypeName) ;
}
} catch ( SQLException e) {
System. out . println( "------------------查表信息异常------------------" ) ;
e. printStackTrace( ) ;
System. out . println( "------------------查表信息异常------------------" ) ;
}
}
public void closeAll( ) {
try {
if ( res != null ) {
res. close ( ) ;
}
if ( sta != null ) {
sta. close ( ) ;
}
if ( con != null ) {
con. close ( ) ;
}
}catch ( SQLException e) {
e. printStackTrace( ) ;
}
}
}
import java. sql . Connection;
import java. sql . ResultSet;
public class test {
public static void main( String[ ] args) {
connectionMysql con = new connectionMysql( ) ;
Connection connection = con. openMysql( ) ;
con. update ( "delete from stumess where sid=2" ) ;
ResultSet resultSet = con. select ( "select * from stumess" ) ;
System. out . println( resultSet) ;
}
}