系统集成语言Ballerina介绍

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)
       };
   }
}