Added Spring Boot role based security sample application

3 files changed, 185 insertions, 0 deletions

diff --git a/spring-boot/10-role-based-security/src/main/java/com/example/spring/security/entity/User.java b/spring-boot/10-role-based-security/src/main/java/com/example/spring/security/entity/User.java
new file mode 100644
index 0000000..72c413a
--- /dev/null
+++ b/spring-boot/10-role-based-security/src/main/java/com/example/spring/security/entity/User.java
@@ -0,0 +1,147 @@
+package com.example.spring.security.entity;
+
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.Date;
+import java.util.HashSet;
+import java.util.Set;
+import java.util.stream.Collectors;
+
+import org.hibernate.annotations.CreationTimestamp;
+import org.hibernate.annotations.UpdateTimestamp;
+import org.springframework.security.core.GrantedAuthority;
+import org.springframework.security.core.authority.SimpleGrantedAuthority;
+import org.springframework.security.core.userdetails.UserDetails;
+
+import jakarta.persistence.CollectionTable;
+import jakarta.persistence.Column;
+import jakarta.persistence.ElementCollection;
+import jakarta.persistence.Entity;
+import jakarta.persistence.FetchType;
+import jakarta.persistence.GeneratedValue;
+import jakarta.persistence.GenerationType;
+import jakarta.persistence.Id;
+import jakarta.persistence.JoinColumn;
+import jakarta.persistence.Table;
+
+/*
+    @Table - Used to set the database table name explicitely.
+*/
+@Entity
+@Table(name = "user_account")
+public class User implements UserDetails {
+
+    /*
+     * GenerationType.IDENTITY - Auto generate value based on database's native auto
+     * increment feature
+     */
+    @Id
+    @GeneratedValue(strategy = GenerationType.IDENTITY)
+    private Long id;
+
+    @Column(unique = true)
+    private String username;
+
+    private String password;
+
+    @Column(nullable = false)
+    private String description;
+
+    @CreationTimestamp
+    @Column(updatable = false, name = "created_at")
+    private Date createdAt;
+
+    @UpdateTimestamp
+    @Column(name = "updated_at")
+    private Date updatedAt;
+
+    /*
+     * @ElementCollection: Marks the field as a collection of basic types (Strings,
+     * Integers, etc.) or embeddable objects.
+     * 
+     * @CollectionTable: Customizes the junction table details. If omitted, JPA
+     * generates a default table name combining the entity name and the field name
+     * (e.g., User_roles).
+     * 
+     * @Column: Defines the column name for the String values inside the collection
+     * table.
+     * 
+     * Fetch Type: By default, element collections use FetchType.LAZY. If you access
+     * the set outside of an active transaction or Hibernate session, it throws a
+     * LazyInitializationException. You can switch it to fetch = FetchType.EAGER to
+     * load the strings immediately alongside the main entity.
+     * 
+     */
+    @ElementCollection(fetch = FetchType.EAGER)
+    @CollectionTable(name = "user_roles", // Name of the separate collection table
+            joinColumns = @JoinColumn(name = "user_id") // Foreign key linking back to this entity
+    )
+    @Column(name = "role_name") // Name of the column storing the actual String values
+    private Set<String> roles = new HashSet<>(); // e.g., ["ADMIN", "USER"]
+
+    @Override
+    public Collection<? extends GrantedAuthority> getAuthorities() {
+        return roles.stream()
+                .map(role -> new SimpleGrantedAuthority("ROLE_" + role))
+                .collect(Collectors.toList());
+    }
+
+    @Override
+    public String getPassword() {
+        return password;
+    }
+
+    @Override
+    public String getUsername() {
+        return username;
+    }
+
+    public Long getId() {
+        return id;
+    }
+
+    public void setId(Long id) {
+        this.id = id;
+    }
+
+    public void setUsername(String username) {
+        this.username = username;
+    }
+
+    public void setPassword(String password) {
+        this.password = password;
+    }
+
+    public String getDescription() {
+        return description;
+    }
+
+    public void setDescription(String description) {
+        this.description = description;
+    }
+
+    public Date getCreatedAt() {
+        return createdAt;
+    }
+
+    public void setCreatedAt(Date createdAt) {
+        this.createdAt = createdAt;
+    }
+
+    public Date getUpdatedAt() {
+        return updatedAt;
+    }
+
+    public void setUpdatedAt(Date updatedAt) {
+        this.updatedAt = updatedAt;
+    }
+
+    public Set<String> getRoles() {
+        return roles;
+    }
+
+    public void setRoles(Set<String> roles) {
+        this.roles = roles;
+    }
+    
+}
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diff --git a/spring-boot/10-role-based-security/src/main/java/com/example/spring/security/repository/UserRepository.java b/spring-boot/10-role-based-security/src/main/java/com/example/spring/security/repository/UserRepository.java
new file mode 100644
index 0000000..f67039c
--- /dev/null
+++ b/spring-boot/10-role-based-security/src/main/java/com/example/spring/security/repository/UserRepository.java
@@ -0,0 +1,13 @@
+package com.example.spring.security.repository;
+
+import java.util.Optional;
+
+import org.springframework.data.repository.ListCrudRepository;
+import org.springframework.stereotype.Repository;
+
+import com.example.spring.security.entity.User;
+
+@Repository
+public interface UserRepository extends ListCrudRepository<User, Long> {
+    Optional<User> findByUsername(String username);
+}
diff --git a/spring-boot/10-role-based-security/src/main/java/com/example/spring/security/service/CustomUserDetailsService.java b/spring-boot/10-role-based-security/src/main/java/com/example/spring/security/service/CustomUserDetailsService.java
new file mode 100644
index 0000000..cdced4a
--- /dev/null
+++ b/spring-boot/10-role-based-security/src/main/java/com/example/spring/security/service/CustomUserDetailsService.java
@@ -0,0 +1,25 @@
+package com.example.spring.security.service;
+
+import org.springframework.security.core.userdetails.UserDetails;
+import org.springframework.security.core.userdetails.UserDetailsService;
+import org.springframework.security.core.userdetails.UsernameNotFoundException;
+import org.springframework.stereotype.Service;
+
+import com.example.spring.security.repository.UserRepository;
+
+@Service
+public class CustomUserDetailsService implements UserDetailsService {
+
+    private final UserRepository userRepository;
+
+    public CustomUserDetailsService(UserRepository userRepository) {
+        this.userRepository = userRepository;
+    }
+
+    @Override
+    public UserDetails loadUserByUsername(String username) throws UsernameNotFoundException {
+        return userRepository.findByUsername(username)
+                .orElseThrow(() -> new UsernameNotFoundException("User not found"));
+    }
+
+}
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