diff --git a/persistence-modules/core-java-persistence-3/pom.xml b/persistence-modules/core-java-persistence-3/pom.xml new file mode 100644 index 0000000000..6868da27be --- /dev/null +++ b/persistence-modules/core-java-persistence-3/pom.xml @@ -0,0 +1,35 @@ + + 4.0.0 + com.baeldung.core-java-persistence-3 + core-java-persistence-3 + core-java-persistence-3 + 0.1.0-SNAPSHOT + jar + + com.baeldung + persistence-modules + 1.0.0-SNAPSHOT + + + + com.h2database + h2 + ${h2.version} + + + org.springframework + spring-jdbc + ${spring-jdbc.version} + + + commons-dbutils + commons-dbutils + ${commons-dbutils.version} + + + + 2.1.214 + 5.3.29 + 1.8.1 + + \ No newline at end of file diff --git a/persistence-modules/core-java-persistence-3/src/test/java/com/baeldung/resultsettomap/ResultSetToMapUnitTest.java b/persistence-modules/core-java-persistence-3/src/test/java/com/baeldung/resultsettomap/ResultSetToMapUnitTest.java new file mode 100644 index 0000000000..b483cc04c9 --- /dev/null +++ b/persistence-modules/core-java-persistence-3/src/test/java/com/baeldung/resultsettomap/ResultSetToMapUnitTest.java @@ -0,0 +1,105 @@ +package com.baeldung.resultsettomap; + +import static org.junit.jupiter.api.Assertions.assertEquals; + +import java.sql.Connection; +import java.sql.DriverManager; +import java.sql.ResultSet; +import java.sql.SQLException; +import java.sql.Statement; +import java.util.ArrayList; +import java.util.Arrays; +import java.util.HashMap; +import java.util.List; +import java.util.Map; + +import org.apache.commons.dbutils.QueryRunner; +import org.apache.commons.dbutils.ResultSetHandler; +import org.junit.After; +import org.junit.Before; +import org.junit.Test; + +public class ResultSetToMapUnitTest { + private static Connection connection = null; + private static final String JDBC_URL = "jdbc:h2:mem:testDatabase"; + private static final String USERNAME = "dbUser"; + private static final String PASSWORD = "dbPassword"; + + @Before + public void setup() throws Exception { + connection = DriverManager.getConnection(JDBC_URL, USERNAME, PASSWORD); + initialDataSetup(); + } + + private void initialDataSetup() throws SQLException { + Statement statement = connection.createStatement(); + String sql = "CREATE TABLE EMPLOYEE (empId INTEGER not null, empName VARCHAR(50), empCity VARCHAR(50), PRIMARY KEY (empId))"; + statement.executeUpdate(sql); + List sqlQueryList = Arrays.asList("INSERT INTO EMPLOYEE VALUES (1, 'Steve','London')", "INSERT INTO EMPLOYEE VALUES (2, 'John','London')", "INSERT INTO EMPLOYEE VALUES (3, 'David', 'Sydney')", + "INSERT INTO EMPLOYEE VALUES (4, 'Kevin','London')", "INSERT INTO EMPLOYEE VALUES (5, 'Jade', 'Sydney')"); + for (String query : sqlQueryList) { + statement.executeUpdate(query); + } + } + + @Test + public void whenUsingNativeJava_thenConvertResultSetToMap() throws SQLException { + ResultSet resultSet = connection.prepareStatement("SELECT * FROM EMPLOYEE") + .executeQuery(); + Map> valueMap = new HashMap<>(); + + while (resultSet.next()) { + String empCity = resultSet.getString("empCity"); + String empName = resultSet.getString("empName"); + if (!valueMap.containsKey(empCity)) { + valueMap.putIfAbsent(empCity, new ArrayList<>()); + } + valueMap.get(empCity) + .add(empName); + } + assertEquals(3, valueMap.get("London") + .size()); + } + + @Test + public void whenUsingLambda_thenConvertResultSetToMap() throws SQLException { + ResultSet resultSet = connection.prepareStatement("SELECT * FROM EMPLOYEE") + .executeQuery(); + Map> valueMap = new HashMap<>(); + + while (resultSet.next()) { + String empCity = resultSet.getString("empCity"); + String empName = resultSet.getString("empName"); + valueMap.computeIfAbsent(empCity, data -> new ArrayList<>()) + .add(empName); + } + assertEquals(3, valueMap.get("London") + .size()); + } + + @Test + public void whenUsingDbUtils_thenConvertResultSetToMap() throws SQLException { + + ResultSetHandler>> handler = new ResultSetHandler>>() { + public Map> handle(ResultSet resultSet) throws SQLException { + Map> result = new HashMap<>(); + while (resultSet.next()) { + String empCity = resultSet.getString("empCity"); + String empName = resultSet.getString("empName"); + result.computeIfAbsent(empCity, data -> new ArrayList<>()) + .add(empName); + } + return result; + } + }; + QueryRunner run = new QueryRunner(); + Map> valueMap = run.query(connection, "SELECT * FROM EMPLOYEE", handler); + assertEquals(3, valueMap.get("London") + .size()); + } + + @After + public void preDestroy() throws Exception { + connection.close(); + } +} diff --git a/persistence-modules/pom.xml b/persistence-modules/pom.xml index a99a180390..162894f1e0 100644 --- a/persistence-modules/pom.xml +++ b/persistence-modules/pom.xml @@ -21,6 +21,7 @@ blaze-persistence core-java-persistence core-java-persistence-2 + core-java-persistence-3 elasticsearch flyway flyway-repair