Code samples for Validate Spring Boot Configuration Parameters at Startup

Author: yavuztas

spring-boot/configuration/src/main/java/io/reflectoring/validation/AppConfiguration.java

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+package io.reflectoring.validation;
+
+import org.springframework.boot.context.properties.EnableConfigurationProperties;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+
+@Configuration
+@EnableConfigurationProperties(AppProperties.class)
+class AppConfiguration {
+
+    @Bean
+    public static ReportEmailAddressValidator configurationPropertiesValidator() {
+        return new ReportEmailAddressValidator();
+    }
+
+}

spring-boot/configuration/src/main/java/io/reflectoring/validation/AppProperties.java

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+package io.reflectoring.validation;
+
+import org.springframework.boot.context.properties.ConfigurationProperties;
+import org.springframework.validation.annotation.Validated;
+
+import javax.validation.Valid;
+import javax.validation.constraints.NotEmpty;
+
+@Validated
+@ConfigurationProperties(prefix = "app.properties")
+class AppProperties {
+
+    @NotEmpty
+    private String name;
+
+    @Valid
+    private ReportProperties report;
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    public ReportProperties getReport() {
+        return report;
+    }
+
+    public void setReport(ReportProperties report) {
+        this.report = report;
+    }
+}

spring-boot/configuration/src/main/java/io/reflectoring/validation/ReportEmailAddressValidator.java

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+package io.reflectoring.validation;
+
+import org.springframework.validation.Errors;
+import org.springframework.validation.ValidationUtils;
+import org.springframework.validation.Validator;
+
+class ReportEmailAddressValidator implements Validator {
+
+    private static final String EMAIL_DOMAIN = "@analysisapp.com";
+
+    public boolean supports(Class clazz) {
+        return ReportProperties.class.isAssignableFrom(clazz);
+    }
+
+    public void validate(Object target, Errors errors) {
+
+        ValidationUtils.rejectIfEmptyOrWhitespace(errors, "emailAddress", "field.required");
+
+        ReportProperties reportProperties = (ReportProperties) target;
+        if (!reportProperties.getEmailAddress().endsWith(EMAIL_DOMAIN)) {
+            errors.rejectValue("emailAddress", "field.domain.required",
+                    new Object[]{EMAIL_DOMAIN},
+                    "The email address must contain [" + EMAIL_DOMAIN + "] domain");
+        }
+
+    }
+}

spring-boot/configuration/src/main/java/io/reflectoring/validation/ReportProperties.java

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+package io.reflectoring.validation;
+
+import javax.validation.constraints.Email;
+import javax.validation.constraints.Max;
+import javax.validation.constraints.Min;
+
+class ReportProperties {
+
+    private Boolean sendEmails = Boolean.FALSE;
+
+    private ReportType type = ReportType.HTML;
+
+    @Min(value = 7)
+    @Max(value = 30)
+    private Integer intervalInDays;
+
+    @Email
+    private String emailAddress;
+
+    public Boolean getSendEmails() {
+        return sendEmails;
+    }
+
+    public void setSendEmails(Boolean sendEmails) {
+        this.sendEmails = sendEmails;
+    }
+
+    public ReportType getType() {
+        return type;
+    }
+
+    public void setType(ReportType type) {
+        this.type = type;
+    }
+
+    public Integer getIntervalInDays() {
+        return intervalInDays;
+    }
+
+    public void setIntervalInDays(Integer intervalInDays) {
+        this.intervalInDays = intervalInDays;
+    }
+
+    public String getEmailAddress() {
+        return emailAddress;
+    }
+
+    public void setEmailAddress(String emailAddress) {
+        this.emailAddress = emailAddress;
+    }
+}

spring-boot/configuration/src/main/java/io/reflectoring/validation/ReportType.java

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+package io.reflectoring.validation;
+
+enum ReportType {
+    HTML, PLAIN_TEXT
+}

spring-boot/configuration/src/main/java/io/reflectoring/validation/ValidationApplication.java

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+package io.reflectoring.validation;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+import org.springframework.context.annotation.PropertySource;
+
+@SpringBootApplication
+@PropertySource("classpath:application-validation.properties")
+public class ValidationApplication {
+
+    public static void main(String[] args) {
+        SpringApplication.run(ValidationApplication.class, args);
+    }
+
+}

spring-boot/configuration/src/main/resources/application-validation.properties

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+app.properties.name=Analysis Application
+app.properties.report.send-emails=true
+app.properties.report.type=PLAIN_TEXT
+app.properties.report.interval-in-days=14
+app.properties.report.email-address[email protected]

spring-boot/configuration/src/test/java/io/reflectoring/validation/AppPropertiesInvalidInputTest.java

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+package io.reflectoring.validation;
+
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.context.properties.ConfigurationPropertiesBindException;
+import org.springframework.boot.context.properties.bind.validation.BindValidationException;
+import org.springframework.core.env.ConfigurableEnvironment;
+import org.springframework.core.env.MutablePropertySources;
+import org.springframework.core.env.PropertiesPropertySource;
+import org.springframework.core.env.StandardEnvironment;
+
+import java.util.Properties;
+
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
+
+/**
+ * We create Spring Application dynamically to catch and test application context startup exceptions
+ */
+class AppPropertiesInvalidInputTest {
+
+    SpringApplication application;
+    Properties properties;
+
+    @BeforeEach
+    void setup() {
+        // create Spring Application dynamically
+        application = new SpringApplication(ValidationApplication.class);
+
+        // setting test properties for our Spring Application
+        properties = new Properties();
+
+        ConfigurableEnvironment environment = new StandardEnvironment();
+        MutablePropertySources propertySources = environment.getPropertySources();
+        propertySources.addFirst(new PropertiesPropertySource("application-test", properties));
+        application.setEnvironment(environment);
+    }
+
+    @Test
+    void whenGivenNameEmpty_thenNotEmptyValidationFails() {
+
+        properties.put("app.properties.name", "");
+
+        assertThatThrownBy(application::run)
+                .isInstanceOf(ConfigurationPropertiesBindException.class)
+                .hasRootCauseInstanceOf(BindValidationException.class)
+                .hasStackTraceContaining("Field error in object 'app.properties' on field 'name'")
+                .hasStackTraceContaining("[must not be empty]");
+
+    }
+
+    @Test
+    void whenGivenReportIntervalInDaysMoreThan30_thenMaxValidationFails() {
+
+        properties.put("app.properties.report.interval-in-days", "31");
+
+        assertThatThrownBy(application::run)
+                .isInstanceOf(ConfigurationPropertiesBindException.class)
+                .hasRootCauseInstanceOf(BindValidationException.class)
+                .hasStackTraceContaining("Field error in object 'app.properties' on field 'report.intervalInDays'")
+                .hasStackTraceContaining("[must be less than or equal to 30]");
+
+    }
+
+    @Test
+    void whenGivenReportIntervalInDaysLessThan7_thenMinValidationFails() {
+
+        properties.put("app.properties.report.interval-in-days", "6");
+
+        assertThatThrownBy(application::run)
+                .isInstanceOf(ConfigurationPropertiesBindException.class)
+                .hasRootCauseInstanceOf(BindValidationException.class)
+                .hasStackTraceContaining("Field error in object 'app.properties' on field 'report.intervalInDays'")
+                .hasStackTraceContaining("[must be greater than or equal to 7]");
+
+    }
+
+    @Test
+    void whenGivenReportEmailAddressIsNotWellFormed_thenEmailValidationFails() {
+
+        properties.put("app.properties.report.email-address", "manager.analysisapp.com");
+
+        assertThatThrownBy(application::run)
+                .isInstanceOf(ConfigurationPropertiesBindException.class)
+                .hasRootCauseInstanceOf(BindValidationException.class)
+                .hasStackTraceContaining("Field error in object 'app.properties' on field 'report.emailAddress'")
+                .hasStackTraceContaining("[must be a well-formed email address]");
+
+    }
+
+    @Test
+    void whenGivenReportEmailAddressDoesNotContainAnalysisappDomain_thenCustomEmailValidatorFails() {
+
+        properties.put("app.properties.report.email-address", "[email protected]");
+
+        assertThatThrownBy(application::run)
+                .isInstanceOf(ConfigurationPropertiesBindException.class)
+                .hasRootCauseInstanceOf(BindValidationException.class)
+                .hasStackTraceContaining("Field error in object 'app.properties.report' on field 'emailAddress'")
+                .hasStackTraceContaining("[The email address must contain [@analysisapp.com] domain]");
+
+    }
+
+}

spring-boot/configuration/src/test/java/io/reflectoring/validation/AppPropertiesValidInputTest.java

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+package io.reflectoring.validation;
+
+import org.junit.jupiter.api.Test;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.context.SpringBootTest;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+@SpringBootTest(properties = {
+        "app.properties.name=My Test App",
+        "app.properties.report.send-emails=true",
+        "app.properties.report.type=PLAIN_TEXT",
+        "app.properties.report.interval-in-days=14",
+        "[email protected]"
+}, classes = {AppConfiguration.class, AppProperties.class, ReportProperties.class})
+class AppPropertiesValidInputTest {
+
+    @Autowired
+    AppProperties appProperties;
+
+    @Test
+    void propertiesAreLoaded() {
+        assertThat(appProperties).isNotNull();
+        assertThat(appProperties.getName()).isEqualTo("My Test App");
+        assertThat(appProperties.getReport()).isNotNull();
+        assertThat(appProperties.getReport().getSendEmails()).isTrue();
+        assertThat(appProperties.getReport().getType()).isEqualTo(ReportType.PLAIN_TEXT);
+        assertThat(appProperties.getReport().getIntervalInDays()).isEqualTo(14);
+        assertThat(appProperties.getReport().getEmailAddress()).isEqualTo("[email protected]");
+    }
+
+}