BAEL-970 A Guide to Apache Commons DbUtils (#2125)

* BAEL-970 A Guide to Apache Commons DbUtils

* BAEL-970 A Guide to Apache Commons DbUtils

* BAEL-970 A Guide to Apache Commons DbUtils

- Added employeeId to Email class
- Minor corrections

libraries/pom.xml

@@ -227,6 +227,11 @@
             <artifactId>commons-io</artifactId>
             <version>${commons.io.version}</version>
         </dependency>
+        <dependency>
+            <groupId>commons-dbutils</groupId>
+            <artifactId>commons-dbutils</artifactId>
+            <version>${commons.dbutils.version}</version>
+        </dependency>        
         <dependency>
             <groupId>org.apache.flink</groupId>
             <artifactId>flink-core</artifactId>
@@ -369,7 +374,7 @@
         <dependency>
             <groupId>com.h2database</groupId>
             <artifactId>h2</artifactId>
-            <version>1.4.195</version>
+            <version>${h2.version}</version>
         </dependency>
         <dependency>
             <groupId>pl.pragmatists</groupId>
@@ -530,6 +535,8 @@
         <jetty.version>9.4.3.v20170317</jetty.version>
         <httpclient.version>4.5.3</httpclient.version>
         <commons.io.version>2.5</commons.io.version>
+        <commons.dbutils.version>1.6</commons.dbutils.version>
+        <h2.version>1.4.196</h2.version>
         <jetty.version>9.4.2.v20170220</jetty.version>
         <httpclient.version>4.5.3</httpclient.version>
         <commons.io.version>2.5</commons.io.version>

libraries/src/main/java/com/baeldung/commons/dbutils/Email.java

@@ -0,0 +1,38 @@
+package com.baeldung.commons.dbutils;
+
+public class Email {
+    private Integer id;
+    private Integer employeeId;
+    private String address;
+
+    public Integer getId() {
+        return id;
+    }
+
+    public void setId(Integer id) {
+        this.id = id;
+    }
+
+    public Integer getEmployeeId() {
+        return employeeId;
+    }
+
+    public void setEmployeeId(Integer employeeId) {
+        this.employeeId = employeeId;
+    }
+    
+
+    public String getAddress() {
+        return address;
+    }
+
+    public void setAddress(String address) {
+        this.address = address;
+    }
+
+    @Override
+    public String toString() {
+        return "Email{" + "id=" + id + ", address=" + address + '}';
+    }
+
+}

libraries/src/main/java/com/baeldung/commons/dbutils/Employee.java

@@ -0,0 +1,67 @@
+package com.baeldung.commons.dbutils;
+
+import java.util.Date;
+import java.util.List;
+
+public class Employee {
+    private Integer id;
+    private String firstName;
+    private String lastName;
+    private Double salary;
+    private Date hiredDate;
+    private List<Email> emails;
+
+    public Integer getId() {
+        return id;
+    }
+
+    public void setId(Integer id) {
+        this.id = id;
+    }
+
+    public String getFirstName() {
+        return firstName;
+    }
+
+    public void setFirstName(String firstName) {
+        this.firstName = firstName;
+    }
+
+    public String getLastName() {
+        return lastName;
+    }
+
+    public void setLastName(String lastName) {
+        this.lastName = lastName;
+    }
+
+    public Double getSalary() {
+        return salary;
+    }
+
+    public void setSalary(Double salary) {
+        this.salary = salary;
+    }
+
+    public Date getHiredDate() {
+        return hiredDate;
+    }
+
+    public void setHiredDate(Date hiredDate) {
+        this.hiredDate = hiredDate;
+    }
+
+    public List<Email> getEmails() {
+        return emails;
+    }
+
+    public void setEmails(List<Email> emails) {
+        this.emails = emails;
+    }
+
+    @Override
+    public String toString() {
+        return "Employee{" + "id=" + id + ", firstName=" + firstName + ", lastName=" + lastName + ", salary=" + salary + ", hiredDate=" + hiredDate + '}';
+    }
+
+}

libraries/src/main/java/com/baeldung/commons/dbutils/EmployeeHandler.java

@@ -0,0 +1,45 @@
+package com.baeldung.commons.dbutils;
+
+import java.sql.Connection;
+import java.sql.ResultSet;
+import java.sql.SQLException;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import org.apache.commons.dbutils.BasicRowProcessor;
+import org.apache.commons.dbutils.BeanProcessor;
+
+import org.apache.commons.dbutils.QueryRunner;
+import org.apache.commons.dbutils.handlers.BeanListHandler;
+
+public class EmployeeHandler extends BeanListHandler<Employee> {
+
+    private Connection connection;
+
+    public EmployeeHandler(Connection con) {
+        super(Employee.class, new BasicRowProcessor(new BeanProcessor(getColumnsToFieldsMap())));
+        this.connection = con;
+    }
+
+    @Override
+    public List<Employee> handle(ResultSet rs) throws SQLException {
+        List<Employee> employees = super.handle(rs);
+
+        QueryRunner runner = new QueryRunner();
+        BeanListHandler<Email> handler = new BeanListHandler<>(Email.class);
+        String query = "SELECT * FROM email WHERE employeeid = ?";
+        for (Employee employee : employees) {
+            List<Email> emails = runner.query(connection, query, handler, employee.getId());
+            employee.setEmails(emails);
+        }
+        return employees;
+    }
+
+    public static Map<String, String> getColumnsToFieldsMap() {
+        Map<String, String> columnsToFieldsMap = new HashMap<>();
+        columnsToFieldsMap.put("FIRST_NAME", "firstName");
+        columnsToFieldsMap.put("LAST_NAME", "lastName");
+        columnsToFieldsMap.put("HIRED_DATE", "hiredDate");
+        return columnsToFieldsMap;
+    }
+}

libraries/src/test/java/com/baeldung/commons/dbutils/DbUtilsUnitTest.java

@@ -0,0 +1,160 @@
+package com.baeldung.commons.dbutils;
+
+import java.sql.Connection;
+import java.sql.DriverManager;
+import java.sql.SQLException;
+import java.util.Date;
+import java.util.List;
+import java.util.Map;
+import java.util.concurrent.Executors;
+import java.util.concurrent.Future;
+import java.util.concurrent.TimeUnit;
+import org.apache.commons.dbutils.AsyncQueryRunner;
+import org.apache.commons.dbutils.DbUtils;
+import org.apache.commons.dbutils.QueryRunner;
+import org.apache.commons.dbutils.handlers.BeanListHandler;
+import org.apache.commons.dbutils.handlers.MapListHandler;
+import org.apache.commons.dbutils.handlers.ScalarHandler;
+import org.junit.After;
+import static org.junit.Assert.*;
+import org.junit.Before;
+import org.junit.Test;
+
+public class DbUtilsUnitTest {
+
+    private Connection connection;
+
+    @Before
+    public void setupDB() throws Exception {
+        Class.forName("org.h2.Driver");
+        String db = "jdbc:h2:mem:;INIT=runscript from 'classpath:/employees.sql'";
+        connection = DriverManager.getConnection(db);
+    }
+
+    @After
+    public void closeBD() {
+        DbUtils.closeQuietly(connection);
+    }
+
+    @Test
+    public void givenResultHandler_whenExecutingQuery_thenExpectedList() throws SQLException {
+        MapListHandler beanListHandler = new MapListHandler();
+
+        QueryRunner runner = new QueryRunner();
+        List<Map<String, Object>> list = runner.query(connection, "SELECT * FROM employee", beanListHandler);
+
+        assertEquals(list.size(), 5);
+        assertEquals(list.get(0)
+            .get("firstname"), "John");
+        assertEquals(list.get(4)
+            .get("firstname"), "Christian");
+    }
+
+    @Test
+    public void givenResultHandler_whenExecutingQuery_thenEmployeeList() throws SQLException {
+        BeanListHandler<Employee> beanListHandler = new BeanListHandler<>(Employee.class);
+
+        QueryRunner runner = new QueryRunner();
+        List<Employee> employeeList = runner.query(connection, "SELECT * FROM employee", beanListHandler);
+
+        assertEquals(employeeList.size(), 5);
+        assertEquals(employeeList.get(0)
+            .getFirstName(), "John");
+        assertEquals(employeeList.get(4)
+            .getFirstName(), "Christian");
+    }
+
+    @Test
+    public void givenResultHandler_whenExecutingQuery_thenExpectedScalar() throws SQLException {
+        ScalarHandler<Long> scalarHandler = new ScalarHandler<>();
+
+        QueryRunner runner = new QueryRunner();
+        String query = "SELECT COUNT(*) FROM employee";
+        long count = runner.query(connection, query, scalarHandler);
+
+        assertEquals(count, 5);
+    }
+
+    @Test
+    public void givenResultHandler_whenExecutingQuery_thenEmailsSetted() throws SQLException {
+        EmployeeHandler employeeHandler = new EmployeeHandler(connection);
+
+        QueryRunner runner = new QueryRunner();
+        List<Employee> employees = runner.query(connection, "SELECT * FROM employee", employeeHandler);
+
+        assertEquals(employees.get(0)
+            .getEmails()
+            .size(), 2);
+        assertEquals(employees.get(2)
+            .getEmails()
+            .size(), 3);
+        assertNotNull(employees.get(0).getEmails().get(0).getEmployeeId());
+    }
+
+    @Test
+    public void givenResultHandler_whenExecutingQuery_thenAllPropertiesSetted() throws SQLException {
+        EmployeeHandler employeeHandler = new EmployeeHandler(connection);
+
+        QueryRunner runner = new QueryRunner();
+        String query = "SELECT * FROM employee_legacy";
+        List<Employee> employees = runner.query(connection, query, employeeHandler);
+
+        assertEquals((int) employees.get(0).getId(), 1);
+        assertEquals(employees.get(0).getFirstName(), "John");
+    }
+
+    @Test
+    public void whenInserting_thenInserted() throws SQLException {
+        QueryRunner runner = new QueryRunner();
+        String insertSQL = "INSERT INTO employee (firstname,lastname,salary, hireddate) VALUES (?, ?, ?, ?)";
+
+        int numRowsInserted = runner.update(connection, insertSQL, "Leia", "Kane", 60000.60, new Date());
+
+        assertEquals(numRowsInserted, 1);
+    }
+
+    @Test
+    public void givenHandler_whenInserting_thenExpectedId() throws SQLException {
+        ScalarHandler<Integer> scalarHandler = new ScalarHandler<>();
+
+        QueryRunner runner = new QueryRunner();
+        String insertSQL = "INSERT INTO employee (firstname,lastname,salary, hireddate) VALUES (?, ?, ?, ?)";
+
+        int newId = runner.insert(connection, insertSQL, scalarHandler, "Jenny", "Medici", 60000.60, new Date());
+
+        assertEquals(newId, 6);
+    }
+
+    @Test
+    public void givenSalary_whenUpdating_thenUpdated() throws SQLException {
+        double salary = 35000;
+
+        QueryRunner runner = new QueryRunner();
+        String updateSQL = "UPDATE employee SET salary = salary * 1.1 WHERE salary <= ?";
+        int numRowsUpdated = runner.update(connection, updateSQL, salary);
+
+        assertEquals(numRowsUpdated, 3);
+    }
+
+    @Test
+    public void whenDeletingRecord_thenDeleted() throws SQLException {
+        QueryRunner runner = new QueryRunner();
+        String deleteSQL = "DELETE FROM employee WHERE id = ?";
+        int numRowsDeleted = runner.update(connection, deleteSQL, 3);
+
+        assertEquals(numRowsDeleted, 1);
+    }
+
+    @Test
+    public void givenAsyncRunner_whenExecutingQuery_thenExpectedList() throws Exception {
+        AsyncQueryRunner runner = new AsyncQueryRunner(Executors.newCachedThreadPool());
+
+        EmployeeHandler employeeHandler = new EmployeeHandler(connection);
+        String query = "SELECT * FROM employee";
+        Future<List<Employee>> future = runner.query(connection, query, employeeHandler);
+        List<Employee> employeeList = future.get(10, TimeUnit.SECONDS);
+
+        assertEquals(employeeList.size(), 5);
+    }
+
+}

libraries/src/test/resources/employees.sql

@@ -0,0 +1,43 @@
+CREATE TABLE employee(
+    id int NOT NULL PRIMARY KEY auto_increment,
+    firstname varchar(255),
+    lastname varchar(255),
+    salary double,
+    hireddate date
+);
+
+CREATE TABLE email(
+    id int NOT NULL PRIMARY KEY auto_increment,
+    employeeid int,
+    address varchar(255)
+);
+
+CREATE TABLE employee_legacy(
+    id int NOT NULL PRIMARY KEY auto_increment,
+    first_name varchar(255),
+    last_name varchar(255),
+    salary double,
+    hired_date date
+);
+
+
+INSERT INTO employee (firstname,lastname,salary,hireddate) VALUES ('John', 'Doe', 10000.10, to_date('01-01-2001','dd-mm-yyyy'));
+INSERT INTO employee (firstname,lastname,salary,hireddate) VALUES ('Kevin', 'Smith', 20000.20, to_date('02-02-2002','dd-mm-yyyy'));
+INSERT INTO employee (firstname,lastname,salary,hireddate) VALUES ('Kim', 'Smith', 30000.30, to_date('03-03-2003','dd-mm-yyyy'));
+INSERT INTO employee (firstname,lastname,salary,hireddate) VALUES ('Stephen', 'Torvalds', 40000.40, to_date('04-04-2004','dd-mm-yyyy'));
+INSERT INTO employee (firstname,lastname,salary,hireddate) VALUES ('Christian', 'Reynolds', 50000.50, to_date('05-05-2005','dd-mm-yyyy'));
+
+INSERT INTO employee_legacy (first_name,last_name,salary,hired_date) VALUES ('John', 'Doe', 10000.10, to_date('01-01-2001','dd-mm-yyyy'));
+INSERT INTO employee_legacy (first_name,last_name,salary,hired_date) VALUES ('Kevin', 'Smith', 20000.20, to_date('02-02-2002','dd-mm-yyyy'));
+INSERT INTO employee_legacy (first_name,last_name,salary,hired_date) VALUES ('Kim', 'Smith', 30000.30, to_date('03-03-2003','dd-mm-yyyy'));
+INSERT INTO employee_legacy (first_name,last_name,salary,hired_date) VALUES ('Stephen', 'Torvalds', 40000.40, to_date('04-04-2004','dd-mm-yyyy'));
+INSERT INTO employee_legacy (first_name,last_name,salary,hired_date) VALUES ('Christian', 'Reynolds', 50000.50, to_date('05-05-2005','dd-mm-yyyy'));
+
+INSERT INTO email (employeeid,address) VALUES (1, 'john@baeldung.com');
+INSERT INTO email (employeeid,address) VALUES (1, 'john@gmail.com');
+INSERT INTO email (employeeid,address) VALUES (2, 'kevin@baeldung.com');
+INSERT INTO email (employeeid,address) VALUES (3, 'kim@baeldung.com');
+INSERT INTO email (employeeid,address) VALUES (3, 'kim@gmail.com');
+INSERT INTO email (employeeid,address) VALUES (3, 'kim@outlook.com');
+INSERT INTO email (employeeid,address) VALUES (4, 'stephen@baeldung.com');
+INSERT INTO email (employeeid,address) VALUES (5, 'christian@gmail.com');