add query examples

spring-jdbc/pom.xml

@@ -23,6 +23,12 @@
 
     <dependencies>
 
+        <dependency>
+            <groupId>commons-io</groupId>
+            <artifactId>commons-io</artifactId>
+            <version>2.6</version>
+        </dependency>
+
         <dependency>
             <groupId>org.springframework.boot</groupId>
             <artifactId>spring-boot-starter-jdbc</artifactId>

spring-jdbc/src/main/java/com/mkyong/StartApplication.java

@@ -1,5 +1,7 @@
 package com.mkyong;
 
+import com.mkyong.customer.Customer;
+import com.mkyong.customer.CustomerRepository;
 import com.mkyong.repository.BookRepository;
 import com.mkyong.sp.StoredFunction;
 import com.mkyong.sp.StoredProcedure1;
@@ -33,6 +35,9 @@ public class StartApplication implements CommandLineRunner {
     @Qualifier("namedParameterJdbcBookRepository")  // Test NamedParameterJdbcTemplate
     private BookRepository bookRepository;
 
+    @Autowired
+    CustomerRepository customerRepository;
+
     @Autowired
     TestData storeProcedureTest;
 
@@ -64,11 +69,51 @@ public void run(String... args) {
         //storedProcedure2.start();
         //storedFunction.start();
 
-        start();
+        //startCustomerApp();
+
+        startBookApp();
+
+    }
+
+    // Tested with H2 database
+    void startCustomerApp() {
+
+        jdbcTemplate.execute("DROP TABLE customer IF EXISTS");
+        jdbcTemplate.execute("CREATE TABLE customer(" +
+                "id SERIAL, name VARCHAR(255), age NUMERIC(2), created_date timestamp)");
+
+        List<Customer> list = Arrays.asList(
+                new Customer("Customer A", 19),
+                new Customer("Customer B", 20),
+                new Customer("Customer C", 21),
+                new Customer("Customer D", 22)
+        );
+
+        list.forEach(x -> {
+            log.info("Saving...{}", x.getName());
+            customerRepository.save(x);
+        });
+
+        log.info("[FIND_BY_ID]");
+        log.info("{}", customerRepository.findByCustomerId(1L));
+        log.info("{}", customerRepository.findByCustomerId2(2L));
+        log.info("{}", customerRepository.findByCustomerId3(3L));
+
+        log.info("[FIND_ALL]");
+        log.info("{}", customerRepository.findAll());
+        log.info("{}", customerRepository.findAll2());
+        log.info("{}", customerRepository.findAll3());
+        log.info("{}", customerRepository.findAll4());
+
+        log.info("[FIND_NAME_BY_ID]");
+        log.info("{}", customerRepository.findCustomerNameById(4L));
+
+        log.info("[COUNT]");
+        log.info("{}", customerRepository.count());
 
     }
 
-    void start() {
+    void startBookApp() {
 
         log.info("Creating tables for testing...");
 

spring-jdbc/src/main/java/com/mkyong/customer/Customer.java

@@ -0,0 +1,68 @@
+package com.mkyong.customer;
+
+import java.time.LocalDateTime;
+
+public class Customer {
+
+    private Long ID;
+    private String name;
+    private Integer age;
+    private LocalDateTime createdDate;
+
+    public Customer() {
+    }
+
+    public Customer(String name, Integer age) {
+        this.name = name;
+        this.age = age;
+    }
+
+    public Customer(Long ID, String name, Integer age, LocalDateTime createdDate) {
+        this.ID = ID;
+        this.name = name;
+        this.age = age;
+        this.createdDate = createdDate;
+    }
+
+    @Override
+    public String toString() {
+        return "Customer{" +
+                "ID=" + ID +
+                ", name='" + name + '\'' +
+                ", age=" + age +
+                ", createdDate=" + createdDate +
+                '}';
+    }
+
+    public Long getID() {
+        return ID;
+    }
+
+    public void setID(Long ID) {
+        this.ID = ID;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    public Integer getAge() {
+        return age;
+    }
+
+    public void setAge(Integer age) {
+        this.age = age;
+    }
+
+    public LocalDateTime getCreatedDate() {
+        return createdDate;
+    }
+
+    public void setCreatedDate(LocalDateTime createdDate) {
+        this.createdDate = createdDate;
+    }
+}

spring-jdbc/src/main/java/com/mkyong/customer/CustomerRepository.java

@@ -0,0 +1,138 @@
+package com.mkyong.customer;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.jdbc.core.BeanPropertyRowMapper;
+import org.springframework.jdbc.core.JdbcTemplate;
+import org.springframework.stereotype.Repository;
+
+import java.math.BigDecimal;
+import java.sql.Timestamp;
+import java.time.LocalDateTime;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Map;
+
+@Repository
+public class CustomerRepository {
+
+    @Autowired
+    private JdbcTemplate jdbcTemplate;
+
+    public int save(Customer customer) {
+        return jdbcTemplate.update(
+                "insert into customer (name, age, created_date) values(?,?,?)",
+                customer.getName(), customer.getAge(), LocalDateTime.now());
+    }
+
+    public Customer findByCustomerId(Long id) {
+
+        String sql = "SELECT * FROM CUSTOMER WHERE ID = ?";
+
+        return jdbcTemplate.queryForObject(sql, new Object[]{id}, new CustomerRowMapper());
+
+    }
+
+    public Customer findByCustomerId2(Long id) {
+
+        String sql = "SELECT * FROM CUSTOMER WHERE ID = ?";
+
+        return (Customer) jdbcTemplate.queryForObject(sql, new Object[]{id}, new BeanPropertyRowMapper(Customer.class));
+
+    }
+
+    public Customer findByCustomerId3(Long id) {
+
+        String sql = "SELECT * FROM CUSTOMER WHERE ID = ?";
+
+        return jdbcTemplate.queryForObject(sql, new Object[]{id}, (rs, rowNum) ->
+                new Customer(
+                        rs.getLong("id"),
+                        rs.getString("name"),
+                        rs.getInt("age"),
+                        rs.getTimestamp("created_date").toLocalDateTime()
+                ));
+
+    }
+
+    public List<Customer> findAll() {
+
+        String sql = "SELECT * FROM CUSTOMER";
+
+        List<Customer> customers = new ArrayList<>();
+
+        List<Map<String, Object>> rows = jdbcTemplate.queryForList(sql);
+
+        for (Map row : rows) {
+            Customer obj = new Customer();
+
+            obj.setID(((Integer) row.get("ID")).longValue());
+            //obj.setID(((Long) row.get("ID"))); no, ClassCastException
+            obj.setName((String) row.get("NAME"));
+            obj.setAge(((BigDecimal) row.get("AGE")).intValue()); // Spring returns BigDecimal, need convert
+            obj.setCreatedDate(((Timestamp) row.get("CREATED_DATE")).toLocalDateTime());
+            customers.add(obj);
+        }
+
+        return customers;
+    }
+
+    public List<Customer> findAll2() {
+
+        String sql = "SELECT * FROM CUSTOMER";
+
+        List<Customer> customers = jdbcTemplate.query(
+                sql,
+                new CustomerRowMapper());
+
+        return customers;
+    }
+
+    public List<Customer> findAll3() {
+
+        String sql = "SELECT * FROM CUSTOMER";
+
+        List<Customer> customers = jdbcTemplate.query(
+                sql,
+                new BeanPropertyRowMapper(Customer.class));
+
+        return customers;
+    }
+
+    public List<Customer> findAll4() {
+
+        String sql = "SELECT * FROM CUSTOMER";
+
+        return jdbcTemplate.query(
+                sql,
+                (rs, rowNum) ->
+                        new Customer(
+                                rs.getLong("id"),
+                                rs.getString("name"),
+                                rs.getInt("age"),
+                                rs.getTimestamp("created_date").toLocalDateTime()
+                        )
+        );
+    }
+
+    public String findCustomerNameById(Long id) {
+
+        String sql = "SELECT NAME FROM CUSTOMER WHERE ID = ?";
+
+        return jdbcTemplate.queryForObject(
+                sql, new Object[]{id}, String.class);
+
+    }
+
+    public int count() {
+
+        String sql = "SELECT COUNT(*) FROM CUSTOMER";
+
+        // queryForInt() is Deprecated
+        // https://www.mkyong.com/spring/jdbctemplate-queryforint-is-deprecated/
+        //int total = jdbcTemplate.queryForInt(sql);
+
+        return jdbcTemplate.queryForObject(sql, Integer.class);
+
+    }
+
+}

spring-jdbc/src/main/java/com/mkyong/customer/CustomerRowMapper.java

@@ -0,0 +1,22 @@
+package com.mkyong.customer;
+
+import org.springframework.jdbc.core.RowMapper;
+
+import java.sql.ResultSet;
+import java.sql.SQLException;
+
+public class CustomerRowMapper implements RowMapper<Customer> {
+
+    @Override
+    public Customer mapRow(ResultSet rs, int rowNum) throws SQLException {
+
+        Customer customer = new Customer();
+        customer.setID(rs.getLong("ID"));
+        customer.setName(rs.getString("NAME"));
+        customer.setAge(rs.getInt("AGE"));
+        customer.setCreatedDate(rs.getTimestamp("created_date").toLocalDateTime());
+
+        return customer;
+
+    }
+}

spring-jdbc/src/main/java/com/mkyong/repository/JdbcBookRepository.java

@@ -3,7 +3,6 @@
 import com.mkyong.Book;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.jdbc.core.JdbcTemplate;
-import org.springframework.jdbc.core.namedparam.NamedParameterJdbcTemplate;
 import org.springframework.stereotype.Repository;
 
 import java.math.BigDecimal;