Migrate to Spring Boot 3 from Spring Boot 2

In this tutorial, we'll use OpenRewrite to perform an automated migration from Spring Boot 2.x to Spring Boot 3.2.

Configuration

See various ways you can configure your project to run this recipe on the recipe reference page. This is also where you can find the full list of changes it will make.

Once you've configured your project, you're ready to execute the migration by running mvn rewrite:run or gradlew rewriteRun. After running the migration you can inspect the results with git diff (or equivalent), manually fix anything that wasn't able to be migrated automatically, and commit the results.

Before and After

Example Java Class

Before

package org.openrewrite.example;

import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.MappedSuperclass;
import org.springframework.beans.factory.annotation.Autowired;

public class OwnerController {
    ...

    @Autowired
    public OwnerController(OwnerRepository clinicService) {
        this.owners = clinicService;
    }

    @RequestMapping(value = "/owners/what")
    public String getWhat() {
        return "multiple method types omg";
    }

    @ModelAttribute("owner")
    public Owner findOwner(@PathVariable("ownerId") int ownerId) {
        return this.owners.findById(ownerId);
    }

    @RequestMapping(value = "/owners/{ownerId}/edit", method = POST)
    public String processUpdateOwnerForm(@Valid Owner owner, BindingResult result, @PathVariable("ownerId") int ownerId) {
        if (result.hasErrors()) {
            return VIEWS_OWNER_CREATE_OR_UPDATE_FORM;
        } else {
            owner.setId(ownerId);
            this.owners.save(owner);
            return "redirect:/owners/{ownerId}";
        }
    }

}

After

package org.openrewrite.example;

import jakarta.persistence.GeneratedValue;
import jakarta.persistence.GenerationType;
import jakarta.persistence.Id;
import jakarta.persistence.MappedSuperclass

public class OwnerController {
    ...

    public OwnerController(OwnerRepository clinicService) {
        this.owners = clinicService;
    }

    @GetMapping("/owners/what")
    public String getWhat() {
        return "multiple method types omg";
    }

    @ModelAttribute("owner")
    public Owner findOwner(@PathVariable int ownerId) {
        return this.owners.findById(ownerId);
    }

    @PostMapping("/owners/{ownerId}/edit")
    public String processUpdateOwnerForm(@Valid Owner owner, BindingResult result, @PathVariable int ownerId) {
        if (result.hasErrors()) {
            return VIEWS_OWNER_CREATE_OR_UPDATE_FORM;
        } else {
            owner.setId(ownerId);
            this.owners.save(owner);
            return "redirect:/owners/{ownerId}";
        }
    }
}

Example Java Test

Before

package org.openrewrite.example;

import org.junit.Before;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.test.context.junit4.SpringRunner;

...

@RunWith(SpringRunner.class)
@WebMvcTest(OwnerController.class)
public class OwnerControllerTests {

    @Before
    public void setup() {
        ...
    }

    @Test
    public void testInitCreationForm() throws Exception {
        ...  
    }
}

After

package org.openrewrite.example;

import org.junit.jupiter.api.BeforeEach;
import org.junit.jupiter.api.Test;

...

@WebMvcTest(OwnerController.class)
class OwnerControllerTests {

    @BeforeEach
    void setup() {
        ...
    }

    @Test
    void testInitCreationForm() throws Exception {
        ...  
    }
}

Example application.properties file

Before

spring.datasource.schema=classpath*:db/${database}/schema.sql
spring.datasource.data=classpath*:db/${database}/data.sql

management.contextPath=/manage

After

spring.sql.init.schema-locations=classpath*:db/${database}/schema.sql
spring.sql.init.data-locations=classpath*:db/${database}/data.sql

management.server.base-path=/manage

Example maven pom.xml file

Before

<parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>2.1.18.RELEASE</version>
</parent>

<properties>
    <java.version>11</java.version>
    <wro4j.version>1.9.0</wro4j.version>
    <thymeleaf.version>3.0.15.RELEASE</thymeleaf.version>
</properties>

<dependencies>
    <dependency>
        <groupId>jakarta.inject</groupId>
        <artifactId>jakarta.inject-api</artifactId>
        <version>1.0.3</version>
    </dependency>

    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-actuator</artifactId>
    </dependency>
</dependencies>

After

<parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>3.2.0</version>
</parent>

<properties>
    <java.version>17</java.version>
    <wro4j.version>1.10.1</wro4j.version>
</properties>

<dependencies>
    <dependency>
       <groupId>jakarta.inject</groupId>
       <artifactId>jakarta.inject-api</artifactId>
       <version>2.1.1.MR</version>
    </dependency>

    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-actuator</artifactId>
        <version>3.2.0</version>
    </dependency>
</dependencies>

See how this recipe works across multiple open-source repositories

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Using Moderne to upgrade Spring versions