Learning content: Learn Java Web (Day40)
1. Database Connection Pool
2. java uses CommonsEmail to send e-mail
1. Database Connection Pool
(1) Download dependency packages for DBCP, C3P0, DRUID, Hikaricp connection pools
DBCP: http://commons.apache.org/dbcp/
C3P0: http://sourceforge.net/projects/c3p0/
DRUID: https://druid.apache.org
(2) DBCP, DRUID, Hikaricp connection pools are configured through the db.properties file:
Create the resources directory, create a new db.properties under the directory, and mark resources as Resources Root.
Using connection pools does not require re-creating connections to the database every time. Connections can be obtained directly from the connection pool when they are needed to improve productivity.
url=jdbc:mysql://127.0.0.1/newsmanagersystem?characterEncoding=utf-8&useSSL=false #This can be defaulted and will be automatically identified by url driverClassName=com.mysql.jdbc.Driver username=root password=root ##Initial number of connections, default 0 initialSize=10 #Maximum number of connections, default 8 maxActive=30 #Minimum number of idles minIdle=10 #Get the maximum wait time for a connection in milliseconds maxWait=2000 #Cache PreparedStatement, default false poolPreparedStatements=true #Maximum number of cached PreparedStatements, default-1 (no caching).Cache PreparedStatement is automatically turned on when greater than 0, so the previous sentence can be omitted maxOpenPreparedStatements=20
The corresponding java code is as follows:
public class jdbcUtil {
private static DataSource dataSource;
static {
//Data Source Configuration
Properties properties=new Properties();
//Get the resource file from the class object of the current class
InputStream is = jdbcUtil.class.getClassLoader().getResourceAsStream("druid.properties");
try {
//Load Profile
properties.load(is);
//DataSource returned, not DruidDataSource
dataSource = DruidDataSourceFactory.createDataSource(properties);
} catch (Exception e) {
e.printStackTrace();
}
}
public static Connection getConnection(){
//Get Connections
Connection connection = null;
try {
connection = dataSource.getConnection();
} catch (SQLException e) {
e.printStackTrace();
}
return connection;
}(3) DBCP, DRUID, Hikaricp connection pools are configured by set method
public class DBHelp {
//create data source
private static HikariDataSource dataSource;
static {
//Read Configuration File
try {
InputStream is = DBHelp.class.getClassLoader().getResourceAsStream("db.properties");
Properties properties = new Properties();
//Load Profile
properties.load(is);
//Get profile information
String driver = properties.getProperty("driverClassName");
String url = properties.getProperty("url");
String userName = properties.getProperty("username");
String password = properties.getProperty("password");
//Configure Data Source
dataSource = new HikariDataSource();
dataSource.setJdbcUrl(url);
dataSource.setUsername(userName);
dataSource.setPassword(password);
dataSource.setDriverClassName(driver);
} catch (IOException e) {
e.printStackTrace();
}
}
//Get Database Connection
public Connection getConn() {
Connection conn = null;
try {
conn = dataSource.getConnection();
} catch (SQLException throwables) {
throwables.printStackTrace();
}
return conn;
}
}(4) c3p0 is configured through the c3p0-config.xml file and needs to be placed in the src folder
<?xml version="1.0" encoding="UTF-8"?>
<c3p0-config>
<!-- Default configuration, if not specified -->
<default-config>
<property name="user">zhanghanlun</property>
<property name="password">123456</property>
<property name="jdbcUrl">jdbc:mysql://localhost:3306/zhanghanlun</property>
<property name="driverClass">com.mysql.jdbc.Driver</property>
<property name="checkoutTimeout">30000</property>
<property name="idleConnectionTestPeriod">30</property>
<property name="initialPoolSize">3</property>
<property name="maxIdleTime">30</property>
<property name="maxPoolSize">100</property>
<property name="minPoolSize">2</property>
<property name="maxStatements">200</property>
</default-config>
<!-- Named Configuration,Can be achieved through method calls -->
<named-config name="test">
<property name="user">zhanghanlun</property>
<property name="password">123456</property>
<property name="jdbcUrl">jdbc:mysql://localhost:3306/zhanghanlun</property>
<property name="driverClass">com.mysql.jdbc.Driver</property>
<!-- How many connections to grow at a time if there are not enough data connections in the pool -->
<property name="acquireIncrement">5</property>
<!-- Number of connections when initializing the database connection pool -->
<property name="initialPoolSize">20</property>
<!-- Maximum number of database connections in the database connection pool -->
<property name="maxPoolSize">25</property>
<!-- Minimum number of database connections in the database connection pool -->
<property name="minPoolSize">5</property>
</named-config>
</c3p0-config>Corresponding java code:
//Load a configuration file with the name "test"
private static ComboPooledDataSource dataSource = new ComboPooledDataSource("test");
/**
* Get Connection Connection Connection
* @return
*/
public static Connection getConnection(){
Connection conn = null;
try {
conn = dataSource.getConnection();
} catch (SQLException e) {
e.printStackTrace();
}
return conn;
}(5) c3p0 is configured by set method
private static ComboPooledDataSource dataSource = new ComboPooledDataSource();
/**
* Configure DataSource
*/
public static void configDataSource(){
try {
dataSource.setDriverClass("com.mysql.jdbc.Driver");
dataSource.setJdbcUrl("jdbc:mysql://localhost:3306/zhanghanlun");
dataSource.setUser("zhanghanlun");
dataSource.setPassword("123456");
dataSource.setInitialPoolSize(3);
dataSource.setMaxPoolSize(10);
dataSource.setMinPoolSize(3);
dataSource.setAcquireIncrement(3);
} catch (PropertyVetoException e) {
e.printStackTrace();
}
}
/**
* Get Connection Connection Connection
* @return
*/
public static Connection getConnection(){
Connection conn = null;
configDataSource();
try {
conn = dataSource.getConnection();
} catch (SQLException e) {
e.printStackTrace();
}
return conn;
}2. java uses CommonsEmail to send e-mail
(1) Apache Commons Email provides an API for sending e-mail.It is built on the JavaMail API to simplify it.
Sending mailbox using commos-email.jar requires three jar packages to be imported first
commos-email.jar
mail.jar
activation-1.1.jar
(2) What you need to know to send mail
* Mail Server Address * Mail Server Port * Do I need to verify * Sender Address * Sender User Name * Sender Password * Recipient Address * Mail Subject * Mail Content * Attachments
(3) Mail Receiving and Sending Protocol
The protocol used to send mail is SMTP, and the port number used is 25
The protocol used to receive mail is POP3, and the port number used is 110
(4) Before sending mail by encoding, first modify the mailbox configuration, go to the official website to log in to the mailbox account, select the POP3/SMTP/IMAP option in the settings, and open the service. You will be prompted to enter the authorization code, remember the set authorization code, which is the sender's password for sending mail by commons-email.You can then write code.
(5) commons-email to send ordinary text mail
Email email = new SimpleEmail(); //New Normal Text Mail Object
email.setHostName("smtp.163.com"); //sender address
email.setAuthentication("yang7email@163.com", "nhrxjldwmpxlbdch"); //Sender User Name and Authorization Number
email.setCharset("UTF-8");//Encoding Format
email.setTLS(true);//Whether to use TLS security protocol
try {
email.setFrom("743351804@qq.com"); //Sender Mailbox
email.setSubject("commons email"); //Subject Sent
email.setMsg("This is a plain text message"); //Sent Content
email.addTo("1064289281@qq.com"); //Recipient Mailbox
email.send(); //Send out
} catch (EmailException e) {
e.printStackTrace();
}(6) commons-email to send HTML mail
HtmlEmail email = new HtmlEmail();//New HTML Mail Object
email.setHostName("smtp.163.com");
email.setAuthentication("yang7email@163.com", "ROBQTYBQTQVSQVNW");
email.setCharset("UTF-8");
email.setTLS(true);
try {
email.setFrom("yang7email@163.com");
email.setSubject("Win the prize");
//Send an html message to add a style.Can send pictures, picture address must be server url address
email.setHtmlMsg("<div style = \"font-weight:blod;color:red;\">Five million</div><img src = \"https://pic3.pocoimg.cn/image/poco/works/17/2021/0222/14/16139751885578129_178285158.jpg\">");
email.addTo("1768374916@qq.com");
email.send();
} catch (EmailException e) {
e.printStackTrace();
}(7) commons-email to send mail with attachments
MultiPartEmail email = new MultiPartEmail();//New mail object with attachments
EmailAttachment ea = new EmailAttachment();//Attachments to send
ea.setPath("d:/pic/1.jpg");
email.setHostName("smtp.163.com");
email.setAuthentication("yang7email@163.com", "ROBQTYBQTQVSQVNW");
email.setCharset("UTF-8");
email.setTLS(true);
try {
email.setFrom("yang7email@163.com");
email.setSubject("Win the prize");
email.setMsg("<div style = \"font-weight:blod;color:red;\">Five million</div><img src = \"https://pic3.pocoimg.cn/image/poco/works/17/2021/0222/14/16139751885578129_178285158.jpg\">");
email.addTo("1768374916@qq.com");
email.attach(ea); //Add Attachments to Mail
email.send();
} catch (EmailException e) {
e.printStackTrace();
}(8) Create a tool class, EmailUtil.java, to send mail of different types
public class EmailUtil {
//Set Default Value
private static String hostName = "smtp.163.com";
private static String userName = "yang7email@163.com";
private static String password = "ROBQTYBQTQVSQVNW";
private static String from = "yang7email@163.com";
private static String character = "UTF-8";
static {//Initialization using static blocks
try {
//Getting mapping of email.properties using input streams
InputStream is = EmailUtil.class.getClassLoader().getResourceAsStream("email.properties");
Properties properties = new Properties();
//Load Input Stream
properties.load(is);
//Get profile information
if(properties.getProperty("email_hsotName") != null){
hostName = properties.getProperty("email_hostName");
}
if(properties.getProperty("email_userName") != null){
userName = properties.getProperty("email_userName");
}
if(properties.getProperty("email_password") != null){
password = properties.getProperty("email_password");
}
if(properties.getProperty("email_from") != null){
from = properties.getProperty("email_from");
}
if(properties.getProperty("email_charset") != null){
character = properties.getProperty("email_charset");
}
} catch (IOException e) {
e.printStackTrace();
}
}
public static void sendTxtEmail(String toEmail,String subject,String content){
Email email = new SimpleEmail();
email.setHostName(hostName);
email.setAuthentication(userName, password);
email.setCharset(character);
email.setTLS(true);
try {
email.setFrom(from);
email.setSubject(subject);
email.setMsg(content);
email.addTo(toEmail);
email.send();
} catch (EmailException e) {
e.printStackTrace();
}
}
public static void sendHtmlEmail(String toEmail,String subject,String content){
HtmlEmail email = new HtmlEmail();
email.setHostName(hostName);
email.setAuthentication(userName, password);
email.setCharset(character);
email.setTLS(true);
try {
email.setFrom(from);
email.setSubject(subject);
email.setHtmlMsg(content);
email.addTo(toEmail);
email.send();
} catch (EmailException e) {
e.printStackTrace();
}
}
public static void sendAttacheEmail(String path,String toEmail,String subject,String content){
MultiPartEmail email = new MultiPartEmail();
EmailAttachment ea = new EmailAttachment();
ea.setPath(path);
email.setHostName(hostName);
email.setAuthentication(userName, password);
email.setCharset(character);
email.setTLS(true);
try {
email.setFrom(from);
email.setSubject(subject);
email.setMsg(content);
email.addTo(toEmail);
email.attach(ea);
email.send();
} catch (EmailException e) {
e.printStackTrace();
}
}
}Create Email.properties file for configuration
email_hostName=smtp.163.com email_userName=yang7email@163.com email_password=ROBQTYBQTQVSQVNW email_charset=UTF-8 email_from=yang7email@163.com
test
public static void main(String[] args) {
EmailUtil.sendTxtEmail("1768374916@qq.com","hehe","hahha");
}(9) Send activation mail at the time of registration, and the user clicks on the mail link to send activation code to the server to verify that the registration is successful.
Create Tool Class CodeUtil to Randomly Generate 6-bit Authentication Codes
public class CodeUtil {
public static String getCode(){
String str="ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789";
StringBuilder sb=new StringBuilder(6);
for(int i=0;i<6;i++)
{
char ch=str.charAt(new Random().nextInt(str.length()));
sb.append(ch);
}
return sb.toString();
}
}servlet class
@WebServlet("/user/api/v1")
public class UserServlet extends HttpServlet {
@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
//1. Register an account
//2. Get the verification code jlfadskf
String code = CodeUtil.getCode();
//3. Save the database
//Sending mail wastes time. New thread sends mail
Thread th = new Thread(new Runnable() {
@Override
public void run() {
//The activation mail is sent at the time of registration, and the user clicks on the mail link to send the activation code to the server to verify that the registration is successful.
EmailUtil.sendTxtEmail("1768374916@qq.com", "Registration Activation", "http://localhost/active?code=" + code);
}
});
th.start();
}
}