CentOS7下JSP连接Mysql

　　实验环境如下：

youxi1　　CentOS7.5　　Tomcat8.5.35　　192.168.5.101

youxi2　　CentOS7.5　　Mysql5.7.20　　192.168.5.102

(1).下载Mysql官方提供的连接包

　　网址：https://dev.mysql.com/downloads/connector/j/，选择Platform Independent（平台独立，就是与平台无关）。我这里下载的是mysql-connector-java-8.0.13.tar.gz。

　　下载完成后上传到Tomcat服务器上，我这里是youix1。

(2).在mysql服务器上创建测试数据，并授权

[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).解压文件，将jar包复制到tomcat安装目录下的lib文件夹中，最后重启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<br> -Djava.util.logging.manager=org.apache.juli.ClassLoaderLogManager -Djdk.tls.ephemeralDHKeySize=2048 -Djava.protocol.handler.pkgs=org.apache.catalina.webresources<br> -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<br> -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 2982 0.0 0.0 112720 992 pts/0 S+ 14:33 0:00 grep --color=auto /usr/local/tomcat8.5/
[root@youxi1 ~]# kill -9 2559　　//杀死tomcat
[root@youxi1 ~]# !ps　　//调用最近一次ps开头的命令
ps aux | grep /usr/local/tomcat8.5/　　//显示完整命令
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
Using CATALINA_BASE: /usr/local/tomcat8.5
Using CATALINA_HOME: /usr/local/tomcat8.5
Using CATALINA_TMPDIR: /usr/local/tomcat8.5/temp
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<br> -Djava.util.logging.manager=org.apache.juli.ClassLoaderLogManager -Djdk.tls.ephemeralDHKeySize=2048 -Djava.protocol.handler.pkgs=org.apache.catalina.webresources<br> -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<br> -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).创建测试网页

[root@youxi1 ~]# vim /usr/local/tomcat8.5/webapps/ROOT/mysql.jsp
<%@ page import="java.sql.*"%>
<html>
<body>
<%
Class.forName("com.mysql.cj.jdbc.Driver").newInstance();<br>//url包含了Mysql的IP地址(192.168.5.102)，端口号(3306)，数据库(test_db)，连接用户名和密码(tomcat_user和tomcatpassword)，使用的字符集(utf-8)
String url = "jdbc:mysql://192.168.5.102:3306/test_db?user=tomcat_user&password=tomcatpassword&useUnicode=true&characterEncoding=utf-8";
Connection conn = DriverManager.getConnection(url);
Statement stmt = conn.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE,ResultSet.CONCUR_UPDATABLE);
String sql="select * from java_tb";
ResultSet rs=stmt.executeQuery(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>