initial commit

.gitignore

+HELP.md
+.gradle
+build/
+!gradle/wrapper/gradle-wrapper.jar
+!**/src/main/**
+!**/src/test/**
+
+### STS ###
+.apt_generated
+.classpath
+.factorypath
+.project
+.settings
+.springBeans
+.sts4-cache
+
+### IntelliJ IDEA ###
+.idea
+*.iws
+*.iml
+*.ipr
+out/
+
+### NetBeans ###
+/nbproject/private/
+/nbbuild/
+/dist/
+/nbdist/
+/.nb-gradle/
+
+### VS Code ###
+.vscode/

build.gradle

+plugins {
+	id 'org.springframework.boot' version '2.3.1.RELEASE'
+	id 'io.spring.dependency-management' version '1.0.9.RELEASE'
+	id 'java'
+}
+
+group = 'com.example'
+version = '0.0.1-SNAPSHOT'
+sourceCompatibility = '1.8'
+
+configurations {
+	compileOnly {
+		extendsFrom annotationProcessor
+	}
+}
+
+ext {
+	set('springCloudVersion', "Hoxton.SR1")
+}
+
+
+repositories {
+	mavenCentral()
+}
+
+dependencies {
+	implementation 'org.springframework.boot:spring-boot-starter-security'
+	implementation 'org.springframework.boot:spring-boot-starter-web'
+	compile group: 'io.jsonwebtoken', name: 'jjwt', version: '0.9.1'
+	compile group: 'javax.xml.bind', name: 'jaxb-api', version: '2.3.1'
+	compileOnly 'org.projectlombok:lombok'
+	annotationProcessor 'org.projectlombok:lombok'
+	testImplementation('org.springframework.boot:spring-boot-starter-test') {
+		exclude group: 'org.junit.vintage', module: 'junit-vintage-engine'
+	}
+	testImplementation 'org.springframework.security:spring-security-test'
+
+}
+
+test {
+	useJUnitPlatform()
+}

gradle/wrapper/gradle-wrapper.properties

+#Thu Jun 18 16:45:02 IST 2020
+distributionUrl=https\://services.gradle.org/distributions/gradle-6.4.1-all.zip
+distributionBase=GRADLE_USER_HOME
+distributionPath=wrapper/dists
+zipStorePath=wrapper/dists
+zipStoreBase=GRADLE_USER_HOME

gradlew

+#!/usr/bin/env sh
+
+#
+# Copyright 2015 the original author or authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+##############################################################################
+##
+##  Gradle start up script for UN*X
+##
+##############################################################################
+
+# Attempt to set APP_HOME
+# Resolve links: $0 may be a link
+PRG="$0"
+# Need this for relative symlinks.
+while [ -h "$PRG" ] ; do
+    ls=`ls -ld "$PRG"`
+    link=`expr "$ls" : '.*-> \(.*\)$'`
+    if expr "$link" : '/.*' > /dev/null; then
+        PRG="$link"
+    else
+        PRG=`dirname "$PRG"`"/$link"
+    fi
+done
+SAVED="`pwd`"
+cd "`dirname \"$PRG\"`/" >/dev/null
+APP_HOME="`pwd -P`"
+cd "$SAVED" >/dev/null
+
+APP_NAME="Gradle"
+APP_BASE_NAME=`basename "$0"`
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
+
+# Use the maximum available, or set MAX_FD != -1 to use that value.
+MAX_FD="maximum"
+
+warn () {
+    echo "$*"
+}
+
+die () {
+    echo
+    echo "$*"
+    echo
+    exit 1
+}
+
+# OS specific support (must be 'true' or 'false').
+cygwin=false
+msys=false
+darwin=false
+nonstop=false
+case "`uname`" in
+  CYGWIN* )
+    cygwin=true
+    ;;
+  Darwin* )
+    darwin=true
+    ;;
+  MINGW* )
+    msys=true
+    ;;
+  NONSTOP* )
+    nonstop=true
+    ;;
+esac
+
+CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
+
+
+# Determine the Java command to use to start the JVM.
+if [ -n "$JAVA_HOME" ] ; then
+    if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
+        # IBM's JDK on AIX uses strange locations for the executables
+        JAVACMD="$JAVA_HOME/jre/sh/java"
+    else
+        JAVACMD="$JAVA_HOME/bin/java"
+    fi
+    if [ ! -x "$JAVACMD" ] ; then
+        die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+    fi
+else
+    JAVACMD="java"
+    which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+fi
+
+# Increase the maximum file descriptors if we can.
+if [ "$cygwin" = "false" -a "$darwin" = "false" -a "$nonstop" = "false" ] ; then
+    MAX_FD_LIMIT=`ulimit -H -n`
+    if [ $? -eq 0 ] ; then
+        if [ "$MAX_FD" = "maximum" -o "$MAX_FD" = "max" ] ; then
+            MAX_FD="$MAX_FD_LIMIT"
+        fi
+        ulimit -n $MAX_FD
+        if [ $? -ne 0 ] ; then
+            warn "Could not set maximum file descriptor limit: $MAX_FD"
+        fi
+    else
+        warn "Could not query maximum file descriptor limit: $MAX_FD_LIMIT"
+    fi
+fi
+
+# For Darwin, add options to specify how the application appears in the dock
+if $darwin; then
+    GRADLE_OPTS="$GRADLE_OPTS \"-Xdock:name=$APP_NAME\" \"-Xdock:icon=$APP_HOME/media/gradle.icns\""
+fi
+
+# For Cygwin or MSYS, switch paths to Windows format before running java
+if [ "$cygwin" = "true" -o "$msys" = "true" ] ; then
+    APP_HOME=`cygpath --path --mixed "$APP_HOME"`
+    CLASSPATH=`cygpath --path --mixed "$CLASSPATH"`
+    
+    JAVACMD=`cygpath --unix "$JAVACMD"`
+
+    # We build the pattern for arguments to be converted via cygpath
+    ROOTDIRSRAW=`find -L / -maxdepth 1 -mindepth 1 -type d 2>/dev/null`
+    SEP=""
+    for dir in $ROOTDIRSRAW ; do
+        ROOTDIRS="$ROOTDIRS$SEP$dir"
+        SEP="|"
+    done
+    OURCYGPATTERN="(^($ROOTDIRS))"
+    # Add a user-defined pattern to the cygpath arguments
+    if [ "$GRADLE_CYGPATTERN" != "" ] ; then
+        OURCYGPATTERN="$OURCYGPATTERN|($GRADLE_CYGPATTERN)"
+    fi
+    # Now convert the arguments - kludge to limit ourselves to /bin/sh
+    i=0
+    for arg in "$@" ; do
+        CHECK=`echo "$arg"|egrep -c "$OURCYGPATTERN" -`
+        CHECK2=`echo "$arg"|egrep -c "^-"`                                 ### Determine if an option
+
+        if [ $CHECK -ne 0 ] && [ $CHECK2 -eq 0 ] ; then                    ### Added a condition
+            eval `echo args$i`=`cygpath --path --ignore --mixed "$arg"`
+        else
+            eval `echo args$i`="\"$arg\""
+        fi
+        i=`expr $i + 1`
+    done
+    case $i in
+        0) set -- ;;
+        1) set -- "$args0" ;;
+        2) set -- "$args0" "$args1" ;;
+        3) set -- "$args0" "$args1" "$args2" ;;
+        4) set -- "$args0" "$args1" "$args2" "$args3" ;;
+        5) set -- "$args0" "$args1" "$args2" "$args3" "$args4" ;;
+        6) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" ;;
+        7) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" ;;
+        8) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" ;;
+        9) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" "$args8" ;;
+    esac
+fi
+
+# Escape application args
+save () {
+    for i do printf %s\\n "$i" | sed "s/'/'\\\\''/g;1s/^/'/;\$s/\$/' \\\\/" ; done
+    echo " "
+}
+APP_ARGS=`save "$@"`
+
+# Collect all arguments for the java command, following the shell quoting and substitution rules
+eval set -- $DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS "\"-Dorg.gradle.appname=$APP_BASE_NAME\"" -classpath "\"$CLASSPATH\"" org.gradle.wrapper.GradleWrapperMain "$APP_ARGS"
+
+exec "$JAVACMD" "$@"

gradlew.bat

+@rem
+@rem Copyright 2015 the original author or authors.
+@rem
+@rem Licensed under the Apache License, Version 2.0 (the "License");
+@rem you may not use this file except in compliance with the License.
+@rem You may obtain a copy of the License at
+@rem
+@rem      https://www.apache.org/licenses/LICENSE-2.0
+@rem
+@rem Unless required by applicable law or agreed to in writing, software
+@rem distributed under the License is distributed on an "AS IS" BASIS,
+@rem WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+@rem See the License for the specific language governing permissions and
+@rem limitations under the License.
+@rem
+
+@if "%DEBUG%" == "" @echo off
+@rem ##########################################################################
+@rem
+@rem  Gradle startup script for Windows
+@rem
+@rem ##########################################################################
+
+@rem Set local scope for the variables with windows NT shell
+if "%OS%"=="Windows_NT" setlocal
+
+set DIRNAME=%~dp0
+if "%DIRNAME%" == "" set DIRNAME=.
+set APP_BASE_NAME=%~n0
+set APP_HOME=%DIRNAME%
+
+@rem Resolve any "." and ".." in APP_HOME to make it shorter.
+for %%i in ("%APP_HOME%") do set APP_HOME=%%~fi
+
+@rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+set DEFAULT_JVM_OPTS="-Xmx64m" "-Xms64m"
+
+@rem Find java.exe
+if defined JAVA_HOME goto findJavaFromJavaHome
+
+set JAVA_EXE=java.exe
+%JAVA_EXE% -version >NUL 2>&1
+if "%ERRORLEVEL%" == "0" goto init
+
+echo.
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+echo.
+echo Please set the JAVA_HOME variable in your environment to match the
+echo location of your Java installation.
+
+goto fail
+
+:findJavaFromJavaHome
+set JAVA_HOME=%JAVA_HOME:"=%
+set JAVA_EXE=%JAVA_HOME%/bin/java.exe
+
+if exist "%JAVA_EXE%" goto init
+
+echo.
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
+echo.
+echo Please set the JAVA_HOME variable in your environment to match the
+echo location of your Java installation.
+
+goto fail
+
+:init
+@rem Get command-line arguments, handling Windows variants
+
+if not "%OS%" == "Windows_NT" goto win9xME_args
+
+:win9xME_args
+@rem Slurp the command line arguments.
+set CMD_LINE_ARGS=
+set _SKIP=2
+
+:win9xME_args_slurp
+if "x%~1" == "x" goto execute
+
+set CMD_LINE_ARGS=%*
+
+:execute
+@rem Setup the command line
+
+set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
+
+
+@rem Execute Gradle
+"%JAVA_EXE%" %DEFAULT_JVM_OPTS% %JAVA_OPTS% %GRADLE_OPTS% "-Dorg.gradle.appname=%APP_BASE_NAME%" -classpath "%CLASSPATH%" org.gradle.wrapper.GradleWrapperMain %CMD_LINE_ARGS%
+
+:end
+@rem End local scope for the variables with windows NT shell
+if "%ERRORLEVEL%"=="0" goto mainEnd
+
+:fail
+rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
+rem the _cmd.exe /c_ return code!
+if  not "" == "%GRADLE_EXIT_CONSOLE%" exit 1
+exit /b 1
+
+:mainEnd
+if "%OS%"=="Windows_NT" endlocal
+
+:omega

settings.gradle

+rootProject.name = 'spring-security-demo'

src/main/java/com/example/MyUserDetailsService.java

+package com.example;
+
+import org.springframework.security.core.userdetails.User;
+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 java.util.ArrayList;
+
+@Service
+public class MyUserDetailsService implements UserDetailsService {
+
+    @Override
+    public UserDetails loadUserByUsername(String s) throws UsernameNotFoundException {
+        return new User("foo", "foo",
+                new ArrayList<>());
+    }
+}
\ No newline at end of file

src/main/java/com/example/SecurityConfiguration.java

+/*
+package com.example;
+
+import org.springframework.context.annotation.Bean;
+import org.springframework.security.config.annotation.authentication.builders.AuthenticationManagerBuilder;
+import org.springframework.security.config.annotation.web.builders.HttpSecurity;
+import org.springframework.security.config.annotation.web.configuration.EnableWebSecurity;
+import org.springframework.security.config.annotation.web.configuration.WebSecurityConfigurerAdapter;
+import org.springframework.security.crypto.password.NoOpPasswordEncoder;
+import org.springframework.security.crypto.password.PasswordEncoder;
+
+@EnableWebSecurity
+public class SecurityConfiguration extends WebSecurityConfigurerAdapter {
+    @Override
+    protected void configure(AuthenticationManagerBuilder auth) throws Exception {
+        // Set your configuration on the auth object
+        auth.inMemoryAuthentication()
+                .withUser("blah")
+                .password("blah")
+                .roles("USER")
+                .and()
+                .withUser("foo")
+                .password("foo")
+                .roles("ADMIN");
+    }
+
+    @Bean
+    public PasswordEncoder getPasswordEncoder() {
+        return NoOpPasswordEncoder.getInstance();
+    }
+
+    @Override
+    protected void configure(HttpSecurity http) throws Exception {
+        http.authorizeRequests()
+                .antMatchers("/admin").hasRole("ADMIN")
+                .antMatchers("/user").hasAnyRole("ADMIN", "USER")
+                .antMatchers("/").permitAll()
+                .and().formLogin();
+    }
+}
+*/

src/main/java/com/example/SpringSecurityDemoApplication.java

+package com.example;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+
+@SpringBootApplication
+public class SpringSecurityDemoApplication {
+
+	public static void main(String[] args) {
+		SpringApplication.run(SpringSecurityDemoApplication.class, args);
+	}
+
+}

src/main/java/com/example/WebSecurityConfig.java

+package com.example;
+
+import com.example.security.filter.JwtRequestFilter;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.context.annotation.Bean;
+import org.springframework.security.authentication.AuthenticationManager;
+import org.springframework.security.config.annotation.authentication.builders.AuthenticationManagerBuilder;
+import org.springframework.security.config.annotation.web.builders.HttpSecurity;
+import org.springframework.security.config.annotation.web.configuration.EnableWebSecurity;
+import org.springframework.security.config.annotation.web.configuration.WebSecurityConfigurerAdapter;
+import org.springframework.security.config.http.SessionCreationPolicy;
+import org.springframework.security.core.userdetails.UserDetailsService;
+import org.springframework.security.crypto.password.NoOpPasswordEncoder;
+import org.springframework.security.crypto.password.PasswordEncoder;
+import org.springframework.security.web.authentication.UsernamePasswordAuthenticationFilter;
+
+@EnableWebSecurity
+class WebSecurityConfig extends WebSecurityConfigurerAdapter {
+	@Autowired
+	private UserDetailsService myUserDetailsService;
+	@Autowired
+	private JwtRequestFilter jwtRequestFilter;
+
+	@Autowired
+	public void configureGlobal(AuthenticationManagerBuilder auth) throws Exception {
+		auth.userDetailsService(myUserDetailsService);
+	}
+
+	@Bean
+	public PasswordEncoder passwordEncoder() {
+		return NoOpPasswordEncoder.getInstance();
+	}
+
+	@Override
+	@Bean
+	public AuthenticationManager authenticationManagerBean() throws Exception {
+		return super.authenticationManagerBean();
+	}
+
+	@Override
+	protected void configure(HttpSecurity httpSecurity) throws Exception {
+		httpSecurity.csrf().disable()
+				.authorizeRequests().antMatchers("/authenticate").permitAll().
+						anyRequest().authenticated().and().
+						exceptionHandling().and().sessionManagement()
+				.sessionCreationPolicy(SessionCreationPolicy.STATELESS);
+		httpSecurity.addFilterBefore(jwtRequestFilter, UsernamePasswordAuthenticationFilter.class);
+
+	}
+
+}
\ No newline at end of file

src/main/java/com/example/security/controller/HelloWorldController.java

+package com.example.security.controller;
+
+import com.example.MyUserDetailsService;
+import com.example.security.model.AuthenticationRequest;
+import com.example.security.model.AuthenticationResponse;
+import com.example.security.util.JwtUtil;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.http.ResponseEntity;
+import org.springframework.security.authentication.AuthenticationManager;
+import org.springframework.security.authentication.BadCredentialsException;
+import org.springframework.security.authentication.UsernamePasswordAuthenticationToken;
+import org.springframework.security.core.userdetails.UserDetails;
+import org.springframework.web.bind.annotation.RequestBody;
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RequestMethod;
+import org.springframework.web.bind.annotation.RestController;
+
+@RestController
+class HelloWorldController {
+
+	@Autowired
+	private AuthenticationManager authenticationManager;
+
+	@Autowired
+	private JwtUtil jwtTokenUtil;
+
+	@Autowired
+	private MyUserDetailsService userDetailsService;
+
+	@RequestMapping({ "/hello" })
+	public String firstPage() {
+		return "Hello World";
+	}
+
+	@RequestMapping(value = "/authenticate", method = RequestMethod.POST)
+	public ResponseEntity<?> createAuthenticationToken(@RequestBody AuthenticationRequest authenticationRequest) throws Exception {
+
+		try {
+			authenticationManager.authenticate(
+					new UsernamePasswordAuthenticationToken(authenticationRequest.getUsername(), authenticationRequest.getPassword())
+			);
+		}
+		catch (BadCredentialsException e) {
+			throw new Exception("Incorrect username or password", e);
+		}
+
+
+		final UserDetails userDetails = userDetailsService
+				.loadUserByUsername(authenticationRequest.getUsername());
+
+		final String jwt = jwtTokenUtil.generateToken(userDetails);
+
+		return ResponseEntity.ok(new AuthenticationResponse(jwt));
+	}
+
+}
+

src/main/java/com/example/security/controller/HomeResource.java

+package com.example.security.controller;
+
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.RestController;
+
+@RestController
+public class HomeResource {
+
+    @GetMapping("/")
+    public String home() {
+        return ("<h1>Welcome</h1>");
+    }
+
+    @GetMapping("/user")
+    public String user() {
+        return ("<h1>Welcome User</h1>");
+    }
+
+    @GetMapping("/admin")
+    public String admin() {
+        return ("<h1>Welcome Admin</h1>");
+    }
+}

src/main/java/com/example/security/filter/JwtRequestFilter.java

+package com.example.security.filter;
+
+import com.example.MyUserDetailsService;
+import com.example.security.util.JwtUtil;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.security.authentication.UsernamePasswordAuthenticationToken;
+import org.springframework.security.core.context.SecurityContextHolder;
+import org.springframework.security.core.userdetails.UserDetails;
+import org.springframework.security.web.authentication.WebAuthenticationDetailsSource;
+import org.springframework.stereotype.Component;
+import org.springframework.web.filter.OncePerRequestFilter;
+
+import javax.servlet.FilterChain;
+import javax.servlet.ServletException;
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+import java.io.IOException;
+
+@Component
+public class JwtRequestFilter extends OncePerRequestFilter {
+
+    @Autowired
+    private MyUserDetailsService userDetailsService;
+
+    @Autowired
+    private JwtUtil jwtUtil;
+
+    @Override
+    protected void doFilterInternal(HttpServletRequest request, HttpServletResponse response, FilterChain chain)
+            throws ServletException, IOException {
+
+        final String authorizationHeader = request.getHeader("Authorization");
+
+        String username = null;
+        String jwt = null;
+
+        if (authorizationHeader != null && authorizationHeader.startsWith("Bearer ")) {
+            jwt = authorizationHeader.substring(7);
+            username = jwtUtil.extractUsername(jwt);
+        }
+
+
+        if (username != null && SecurityContextHolder.getContext().getAuthentication() == null) {
+
+            UserDetails userDetails = this.userDetailsService.loadUserByUsername(username);
+
+            if (jwtUtil.validateToken(jwt, userDetails)) {
+
+                UsernamePasswordAuthenticationToken usernamePasswordAuthenticationToken = new UsernamePasswordAuthenticationToken(
+                        userDetails, null, userDetails.getAuthorities());
+                usernamePasswordAuthenticationToken
+                        .setDetails(new WebAuthenticationDetailsSource().buildDetails(request));
+                SecurityContextHolder.getContext().setAuthentication(usernamePasswordAuthenticationToken);
+            }
+        }
+        chain.doFilter(request, response);
+    }
+
+}

src/main/java/com/example/security/model/AuthenticationRequest.java

+package com.example.security.model;
+
+import java.io.Serializable;
+
+public class AuthenticationRequest implements Serializable {
+
+
+    private String username;
+    private String password;
+
+    public String getUsername() {
+        return username;
+    }
+
+    public void setUsername(String username) {
+        this.username = username;
+    }
+
+    public String getPassword() {
+        return password;
+    }
+
+    public void setPassword(String password) {
+        this.password = password;
+    }
+
+    //need default constructor for JSON Parsing
+    public AuthenticationRequest()
+    {
+
+    }
+
+    public AuthenticationRequest(String username, String password) {
+        this.setUsername(username);
+        this.setPassword(password);
+    }
+}

src/main/java/com/example/security/model/AuthenticationResponse.java

+package com.example.security.model;
+
+import java.io.Serializable;
+
+public class AuthenticationResponse implements Serializable {
+
+    private final String jwt;
+
+    public AuthenticationResponse(String jwt) {
+        this.jwt = jwt;
+    }
+
+    public String getJwt() {
+        return jwt;
+    }
+}

src/main/java/com/example/security/util/JwtUtil.java

+package com.example.security.util;
+
+import io.jsonwebtoken.Claims;
+import io.jsonwebtoken.Jwts;
+import io.jsonwebtoken.SignatureAlgorithm;
+import org.springframework.security.core.userdetails.UserDetails;
+import org.springframework.stereotype.Service;
+
+import java.util.Date;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.function.Function;
+
+
+@Service
+public class JwtUtil {
+
+    private String SECRET_KEY = "secret";
+
+    public String extractUsername(String token) {
+        return extractClaim(token, Claims::getSubject);
+    }
+
+    public Date extractExpiration(String token) {
+        return extractClaim(token, Claims::getExpiration);
+    }
+
+    public <T> T extractClaim(String token, Function<Claims, T> claimsResolver) {
+        final Claims claims = extractAllClaims(token);
+        return claimsResolver.apply(claims);
+    }
+    private Claims extractAllClaims(String token) {
+        return Jwts.parser().setSigningKey(SECRET_KEY).parseClaimsJws(token).getBody();
+    }
+
+    private Boolean isTokenExpired(String token) {
+        return extractExpiration(token).before(new Date());
+    }
+
+    public String generateToken(UserDetails userDetails) {
+        Map<String, Object> claims = new HashMap<>();
+        return createToken(claims, userDetails.getUsername());
+    }
+
+    private String createToken(Map<String, Object> claims, String subject) {
+
+        return Jwts.builder().setClaims(claims).setSubject(subject).setIssuedAt(new Date(System.currentTimeMillis()))
+                .setExpiration(new Date(System.currentTimeMillis() + 1000 * 60 * 60 * 10))
+                .signWith(SignatureAlgorithm.HS256, SECRET_KEY).compact();
+    }
+
+    public Boolean validateToken(String token, UserDetails userDetails) {
+        final String username = extractUsername(token);
+        return (username.equals(userDetails.getUsername()) && !isTokenExpired(token));
+    }
+}
\ No newline at end of file

src/main/resources/application.properties

+server.port=8060

src/test/java/com/example/springsecuritydemo/SpringSecurityDemoApplicationTests.java

+package com.example.springsecuritydemo;
+
+import org.junit.jupiter.api.Test;
+import org.springframework.boot.test.context.SpringBootTest;
+
+@SpringBootTest
+class SpringSecurityDemoApplicationTests {
+
+	@Test
+	void contextLoads() {
+	}
+
+}