BAEL-1217 Guide to Spring Type Conversions

Review comments

spring-boot/src/main/java/org/baeldung/converter/GenericBigDecimalConverter.java

@@ -5,6 +5,7 @@ import org.springframework.core.convert.TypeDescriptor;
 import org.springframework.core.convert.converter.GenericConverter;
 
 import java.math.BigDecimal;
+import java.math.MathContext;
 import java.util.Set;
 
 public class GenericBigDecimalConverter implements GenericConverter {
@@ -30,7 +31,9 @@ public class GenericBigDecimalConverter implements GenericConverter {
             return new BigDecimal(number);
         } else {
             Number number = (Number) source;
-            return new BigDecimal(number.doubleValue());
+            BigDecimal converted = new BigDecimal(number.doubleValue());
+            converted.setScale(2, BigDecimal.ROUND_HALF_EVEN);
+            return converted;
         }
     }
 }

spring-boot/src/main/java/org/baeldung/converter/controller/StringToEmployeeConverterController.java

@@ -0,0 +1,21 @@
+package org.baeldung.converter.controller;
+
+import com.baeldung.toggle.Employee;
+import org.springframework.http.MediaType;
+import org.springframework.http.ResponseEntity;
+import org.springframework.web.bind.annotation.*;
+
+@RestController
+@RequestMapping("/string-to-employee")
+public class StringToEmployeeConverterController {
+
+    @GetMapping
+    public ResponseEntity<Object> getStringToEmployee(@RequestParam("employee") Employee employee) {
+        return ResponseEntity.ok(employee);
+    }
+
+    @PostMapping(consumes = {MediaType.TEXT_PLAIN_VALUE})
+    public ResponseEntity<Object> postStringToEmployee(@RequestBody Employee employee) {
+        return ResponseEntity.ok(employee);
+    }
+}

spring-boot/src/test/java/org/baeldung/converter/CustomConverterTest.java

@@ -13,6 +13,8 @@ import org.springframework.test.context.web.WebAppConfiguration;
 
 import java.math.BigDecimal;
 
+import static org.assertj.core.api.Assertions.assertThat;
+
 @RunWith(SpringJUnit4ClassRunner.class)
 @SpringBootTest(classes = Application.class)
 @WebAppConfiguration
@@ -23,23 +25,29 @@ public class CustomConverterTest {
 
     @Test
     public void whenConvertStringToIntegerUsingDefaultConverter_thenSuccess() {
-        System.out.println(conversionService.convert("25", Integer.class));
+        assertThat(conversionService.convert("25", Integer.class)).isEqualTo(25);
     }
 
     @Test
     public void whenConvertStringToEmployee_thenSuccess() {
-        System.out.println(conversionService.convert("1,50000.00", Employee.class));
+        Employee employee = conversionService.convert("1,50000.00", Employee.class);
+        Employee actualEmployee = new Employee(1, 50000.00);
+        assertThat(conversionService.convert("1,50000.00", Employee.class))
+          .isEqualToComparingFieldByField(actualEmployee);
     }
 
     @Test
     public void whenConvertStringToEnum_thenSuccess() {
-        System.out.println(conversionService.convert("ALPHA", Modes.class));
+        assertThat(conversionService.convert("ALPHA", Modes.class)).isEqualTo(Modes.ALPHA);
     }
 
     @Test
     public void whenConvertingToBigDecimalUsingGenericConverter_thenSuccess() {
-        System.out.println(conversionService.convert(Integer.valueOf(11), BigDecimal.class));
-        System.out.println(conversionService.convert(Double.valueOf(25.23), BigDecimal.class));
-        System.out.println(conversionService.convert("2.32", BigDecimal.class));
+        assertThat(conversionService.convert(Integer.valueOf(11), BigDecimal.class)).
+          isEqualTo(BigDecimal.valueOf(11));
+        assertThat(conversionService.convert(Double.valueOf(25.23), BigDecimal.class))
+          .isEqualByComparingTo(BigDecimal.valueOf(Double.valueOf(25.23)));
+        assertThat(conversionService.convert("2.32", BigDecimal.class))
+          .isEqualTo(BigDecimal.valueOf(2.32));
     }
 }

spring-boot/src/test/java/org/baeldung/converter/controller/StringToEmployeeConverterControllerTest.java

@@ -0,0 +1,39 @@
+package org.baeldung.converter.controller;
+
+import org.baeldung.Application;
+import org.baeldung.boot.DemoApplication;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.autoconfigure.jdbc.AutoConfigureTestDatabase;
+import org.springframework.boot.test.autoconfigure.web.servlet.AutoConfigureMockMvc;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.http.MediaType;
+import org.springframework.test.context.junit4.SpringRunner;
+import org.springframework.test.web.servlet.MockMvc;
+
+import static org.hamcrest.CoreMatchers.is;
+import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.get;
+import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.post;
+import static org.springframework.test.web.servlet.result.MockMvcResultHandlers.print;
+import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.jsonPath;
+import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.status;
+
+@RunWith(SpringRunner.class)
+@SpringBootTest(webEnvironment = SpringBootTest.WebEnvironment.RANDOM_PORT, classes = Application.class)
+@AutoConfigureMockMvc
+//@AutoConfigureTestDatabase
+public class StringToEmployeeConverterControllerTest {
+
+    @Autowired
+    private MockMvc mockMvc;
+
+    @Test
+    public void getStringToEmployeeTest() throws Exception {
+        mockMvc.perform(get("/string-to-employee?employee=1,2000"))
+                .andDo(print())
+                .andExpect(jsonPath("$.id", is(1)))
+                .andExpect(jsonPath("$.salary", is(2000.0)))
+                .andExpect(status().isOk());
+    }
+}