系統整合語言Ballerina介紹

import ballerina/config;
import ballerina/h2;
import ballerina/io;
type Student record {
int age;
string firstName;
};
endpoint h2:Client testDB {
path: config:getAsString("DATABASE_PATH", default = "./h2-client"),
name: config:getAsString("DATABASE_PATH", default = "testdb"),
username: config:getAsString("DATABASE_USER", default = "SA"),
password: config:getAsString("DATABASE_PASS", default = ""),
poolOptions: { maximumPoolSize: 5 }
};
function main(string... args) {
//Create Table in a in memory H2 Database
var ret= testDB ->update("CREATE TABLE student(age INT, name VARCHAR(255))");
//Insert data into the table
ret = testDB ->update("INSERT INTO student(age, name) values (?, ?)", 10, "John");
ret = testDB ->update("INSERT INTO student(age, name) values (?, ?)", 20, "Anne");
//Select data from the table
table<Student> tableStudent = check testDB ->select("SELECT * FROM student", 
Student, loadToMemory = true);
//Get the row count
int count = tableStudent .count();
//Convert table into json
json jsonData = check <json>tableStudent;
//Convert table to xml
xml xmlData = check <xml>tableStudent;
//Access each data record
foreach s in tableStudent {
io:println(s);
}
}

import ballerina/http;
import ballerina/log;
import ballerina/mysql;
import ballerina/config;

//Create mysql client endpoint with config for employee db.
endpoint mysql:Client employeeDB {
host: config:getAsString("employeedb.host"),
port: config:getAsInt("employeedb.port"),
name: config:getAsString("employeedb.name"),
username: config:getAsString("employeedb.user"),
password: config:getAsString("employeedb.pass"),
dbOptions: { useSSL: false }
};
//Create mysql client endpoint with config for salary db.
endpoint mysql:Client salaryDB {
host: config:getAsString("salarydb.host"),
port: config:getAsInt("salarydb.port"),
name: config:getAsString("salarydb.name"),
username: config:getAsString("salarydb.user"),
password: config:getAsString("salarydb.pass"),
dbOptions: { useSSL: false }
};
//Employee Add service
@http:ServiceConfig {
basePath: "/hr"
}
service<http:Service> employeeService bind { port: 9090 } {
@http:ResourceConfig {
methods: ["POST"],
path: "/employee"
}
addEmployee(endpoint caller, http:Request req) {
json payload = check req.getJsonPayload();
string name = payload.name.toString();
float salary = check <float> payload.salary;
int age = check <int>payload.age;
int key = -1;
transaction with retries = 2 {
//Update first table and get the generated key
(int, string[]) retWithKey = check employeeDB->updateWithGeneratedKeys(
"INSERT INTO Employee (name, age) VALUES (?,?)", (), name, age);
var (count, ids) = retWithKey;
string generatedKey = ids[0];
key = check <int>generatedKey;
//Update the second table with previous key
var ret = salaryDB->update("INSERT INTO Salary (id, month_salary)
VALUES (?, ?)", key, salary);
} onretry {
log:printError("Transaction failed, retrying ...");
key = -1;
}
//Generate and send the response
http:Response res = new;
res.setPayload("Account added for: " + untaint name + " with ID:" + key + "\n");
caller ->respond(res) but {
error e => log:printError("Error in responding", err = e)
};
}
}