JSP connection Mysql under Linux

　　Experimental environment is as follows:

youxi1　　CentOS7.5　　Tomcat8.5.35　　192.168.5.101

youxi2　　CentOS7.5　　Mysql5.7.20　　192.168.5.102

(1). Mysql link to download the official package

　　URL: https://dev.mysql.com/downloads/connector/j/ , select Platform Independent (platform-independent, that is, regardless of the platform). I am here to download the mysql-connector-java-8.0.13.tar.gz.

　　After the download is complete uploaded to the Tomcat server, I have here is youix1.

(2) Create test data on the mysql server and authorized

[root@youxi2 ~]# mysql -uroot -p123456
mysql> create database test_db; 
Query OK, 1 row affected (0.00 sec)

mysql> use test_db;
Database changed
mysql> create table java_tb(id int,name varchar(20));
Query OK, 0 rows affected (0.02 sec)

mysql> insert into java_tb values(1,'zhangsan'),(2,'lisi');
Query OK, 2 rows affected (0.06 sec)
Records: 2 Duplicates: 0 Warnings: 0

mysql> select * from java_tb;
+------+----------+
| id   | name     |
+------+----------+
|    1 | zhangsan |
|    2 | lisi     |
+------+----------+
2 rows in set (0.00 sec)

mysql> grant all on test_db.* to 'tomcat_user'@'192.168.5.101' identified by 'tomcatpassword';
Query OK, 0 rows affected, 1 warning (0.02 sec)

mysql> flush privileges;　　//刷新
Query OK, 0 rows affected (0.00 sec)

　　

(3) Unzip the file, copy the jar package to the installation directory of tomcat lib folder, and finally restart tomcat

[root@youxi1 ~]# tar zxf mysql-connector-java-8.0.13.tar.gz -C /usr/local/src/　　//解压 
[root@youxi1 ~]# cp /usr/local/src/mysql-connector-java-8.0.13/mysql-connector-java-8.0.13.jar /usr/local/tomcat8.5/lib/　　//复制jar包
[root@youxi1 ~]# ps aux | grep /usr/local/tomcat8.5/
root 2559 0.2 10.0 2325180 99932 ? Sl 12:32 0:21 /usr/local/jdk1.8.0_191/bin/java -Djava.util.logging.config.file=/usr/local/tomcat8.5/conf/logging.properties
 -Djava.util.logging.manager=org.apache.juli.ClassLoaderLogManager -Djdk.tls.ephemeralDHKeySize=2048 -Djava.protocol.handler.pkgs=org.apache.catalina.webresources
 -Dorg.apache.catalina.security.SecurityListener.UMASK=0027 -Dignore.endorsed.dirs= -classpath /usr/local/tomcat8.5/bin/bootstrap.jar:/usr/local/tomcat8.5/bin/tomcat-juli.jar
-Dcatalina.base = / usr / local / tomcat8.5 -Dcatalina.home = / usr / local / tomcat8.5 -Djava.io.tmpdir = / usr / local / tomcat8.5 / temp org.apache.catalina.startup Start .Bootstrap 
the root 992 2982 0.0 0.0 112.72 thousand PTS / S 0 + 14:33 0:00 grep --color = Auto /usr/local/tomcat8.5/ 
[youxi1 the root @ ~] -9 # 2559 // kill the kill tomcat 
[root @ youxi1 ~] # ps // invoke the command ps at the beginning of the last! 
ps the AUX | grep /usr/local/tomcat8.5/ // display the full command 
root 2985 0.0 0.0 112720 992 pts / 0 R + 14:33 0 : 00 = grep --color Auto /usr/local/tomcat8.5/ 
[root @ youxi1 ~] # /usr/local/tomcat8.5/bin/startup.sh 
the Using CATALINA_BASE: /usr/local/tomcat8.5 
the Using CATALINA_HOME: /usr/local/tomcat8.5 
the Using CATALINA_TMPDIR: /usr/local/tomcat8.5/temp 
the Using JRE_HOME: /usr/local/jdk1.8.0_191
Using CLASSPATH: /usr/local/tomcat8.5/bin/bootstrap.jar:/usr/local/tomcat8.5/bin/tomcat-juli.jar
Tomcat started.
[root@youxi1 ~]# !ps
ps aux | grep /usr/local/tomcat8.5/
root 2995 109 6.1 2263640 60904 pts/0 Sl 14:33 0:03 /usr/local/jdk1.8.0_191/bin/java -Djava.util.logging.config.file=/usr/local/tomcat8.5/conf/logging.properties
 -Djava.util.logging.manager=org.apache.juli.ClassLoaderLogManager -Djdk.tls.ephemeralDHKeySize=2048 -Djava.protocol.handler.pkgs=org.apache.catalina.webresources
 -Dorg.apache.catalina.security.SecurityListener.UMASK=0027 -Dignore.endorsed.dirs= -classpath /usr/local/tomcat8.5/bin/bootstrap.jar:/usr/local/tomcat8.5/bin/tomcat-juli.jar
 -Dcatalina.base=/usr/local/tomcat8.5 -Dcatalina.home=/usr/local/tomcat8.5 -Djava.io.tmpdir=/usr/local/tomcat8.5/temp org.apache.catalina.startup.Bootstrap start
root 3015 0.0 0.0 112720 992 pts/0 R+ 14:33 0:00 grep --color=auto /usr/local/tomcat8.5/

(4) Create a test page

[youxi1 the root @ ~] Vim /usr/local/tomcat8.5/webapps/ROOT/mysql.jsp # 
<% @ Page Import = "the java.sql. *"%> 
<HTML> 
<body> 
<% 
the Class.forName ( "com.mysql.cj.jdbc.Driver") newInstance ();. 
// url contains Mysql IP address (192.168.5.102), port number (3306), database (test_db), connected user name and password (tomcat_user and tomcatpassword), using the character set (UTF-8) 
String url = "jdbc: MySQL: //192.168.5.102: 3306 / TEST_DB the User = tomcat_user & password = tomcatpassword & useUnicode = to true & characterEncoding = UTF-8?"; 
Connection conn = DriverManager.getConnection (URL); 
the Statement stmt = conn.createStatement (ResultSet.TYPE_SCROLL_SENSITIVE, ResultSet.CONCUR_UPDATABLE); 
String = SQL "SELECT * from java_tb"; 
the ResultSet stmt.executeQuery RS = (SQL);
while(rs.next()){
%>
id:<%=rs.getString(1)%>
name:<%=rs.getString(2)%><br><br>
<%}%>
<% out.print("Congratulations!!! JSP connect MYSQL IS OK!!"); %>
<%
rs.close();
stmt.close();
conn.close();
%>
</body>
</html>

　　Require the same character set and database side.

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