This time I will show you how to read a Gmail mailbox using POP3 protocol and Java Mail. First you need to define your build.gradle as follow:
def configurationDirectory = "${System.getProperty('user.home')}/.mailbox-reader"
buildscript {
ext {
springBootVersion = '1.5.1.RELEASE'
cglibVersion = '3.2.4'
javaMailVersion = '1.4'
}
repositories {
mavenCentral()
}
dependencies {
classpath("org.springframework.boot:spring-boot-gradle-plugin:${springBootVersion}")
}
}
apply plugin: "groovy"
apply plugin: "application"
apply plugin: 'org.springframework.boot'
jar {
baseName = 'mailbox-reader'
version = '0.0.1-SNAPSHOT'
}
sourceCompatibility = 1.8
repositories {
mavenCentral()
}
dependencies {
compile 'org.springframework.boot:spring-boot-starter'
compile 'org.codehaus.groovy:groovy'
compile "javax.mail:mail:$javaMailVersion"
testCompile 'org.springframework.boot:spring-boot-starter-test'
testCompile 'org.spockframework:spock-spring'
testCompile "cglib:cglib-nodep:$cglibVersion"
}
task settingEnvironment(type:Copy) {
from configurationDirectory
into 'src/main/resources'
include "application.properties"
}
processResources.dependsOn "settingEnvironment"
Then we define a common interface to support different implementations
package com.jos.dem.mailbox.reader.service
interface InboxReader {
void setup()
void read()
}
This is the POP3 mailbox reader implementation
package com.jos.dem.mailbox.reader.service.impl
import org.springframework.stereotype.Service
import org.springframework.beans.factory.annotation.Value
import org.springframework.beans.factory.annotation.Autowired
import javax.mail.Folder
import javax.mail.Message
import javax.mail.Session
import javax.mail.Store
import javax.annotation.PostConstruct
import com.jos.dem.mailbox.reader.service.InboxReader
import org.slf4j.Logger
import org.slf4j.LoggerFactory
@Service
class InboxReaderPop3 implements InboxReader {
@Value('${username}')
String username
@Value('${password}')
String password
@Value('${server}')
String server
@Value('${port}')
String port
Properties properties = new Properties()
Folder emailFolder
Store store
Logger log = LoggerFactory.getLogger(this.class)
@PostConstruct
void setup() {
properties.put('mail.pop3.host', server)
properties.put('mail.pop3.port', port)
properties.put('mail.pop3.starttls.enable', 'true')
Session emailSession = Session.getDefaultInstance(properties)
Store store = emailSession.getStore('pop3s')
store.connect(server, username, password)
emailFolder = store.getFolder('INBOX')
emailFolder.open(Folder.READ_ONLY)
log.info "Inbox Type: ${emailFolder.getType()}"
}
void read(){
Message[] messages = emailFolder.getMessages()
log.info "Messages Length: ${messages.length}"
for (int i = 0; i < messages.length; i++) {
Message message = messages[i]
log.info '--------------------------------'
log.info "Email Number ${(i + 1)}"
log.info "From: ${message.getFrom()[0]}"
log.info "Subject: ${message.getSubject()}"
}
emailFolder.close(false)
}
}
javax.mail.Folder has this types:
- HOLDS_FOLDER = 1
- HOLDS_MESSAGES = 1
- READ_ONLY = 1
- READ_WRITE = 2
Output
Inbox Type: 1
Reading message
Messages Length: 1
--------------------------------
Email Number 1
From: =Jose Luis De la Cruz Morales= <joseluis.delacruz@gmail.com>
Subject: Hello POP3 mailbox reader implementation
Configuration
In your computer’s home directory: ${home}, create a directory called: .mailbox-reader then inside create a file called application.properties with this content
username=user@gmail.com
password=secret
pop3.server=pop.gmail.com
pop3.port=995
imap.server=imap.gmail.com
imap.port=993
Build
gradle build
Run
java -jar build/libs/mailbox-reader-0.0.1-SNAPSHOT.jar
To download the code:
git clone https://github.com/josdem/java-topics.git
cd mailbox-reader