JWT quick start

· What is? JWT？

        JSON Web Token. By means of digital signature , With JSON The object is the carrier , Secure transmission of information between different server terminals .

· JWT What's the usage? ？

        JWT The most common scenario is authorization , Once the user logs in , Each subsequent request will contain JWT, Before each user request is processed by the system , You have to do it first JWT Security check , Process after passing .

· JWT The composition of ：

        JWT from 3 Part of it is made up of , And use . Splicing

for example ： 

These are the three parts （ for example ）：

 · Header

 · Payload

 · Signatrue

First , To achieve jwt You also need to import some packages （ The following is omitted json）

        <!--JWT-->
        <dependency>
            <groupId>io.jsonwebtoken</groupId>
            <artifactId>jjwt</artifactId>
            <version>0.9.1</version>
        </dependency>

        <dependency>
            <groupId>javax.xml.bind</groupId>
            <artifactId>jaxb-api</artifactId>
            <version>2.3.0</version>
        </dependency>

        <dependency>
            <groupId>com.sun.xml.bind</groupId>
            <artifactId>jaxb-impl</artifactId>
            <version>2.3.0</version>
        </dependency>

        <dependency>
            <groupId>com.sun.xml.bind</groupId>
            <artifactId>jaxb-core</artifactId>
            <version>2.3.0</version>
        </dependency>

        <dependency>
            <groupId>javax.activation</groupId>
            <artifactId>activation</artifactId>
            <version>1.1.1</version>
        </dependency>

  practice ： establish token And extraction token Data in

import io.jsonwebtoken.*;
import java.util.Date;
import java.util.UUID;

public class JWT {

    private long time = 1000*60*60*24;
    private String signature = "admin";
    @org.junit.Test
    public void makeJWT(){
        JwtBuilder jwtBuilder = Jwts.builder();
        String jwtToken = jwtBuilder
                //header
                .setHeaderParam("typ","JWT")
                .setHeaderParam("alg","HS256")
                //payload
                .claim("username","tom")
                .claim("role","admin")
                .setSubject("admin-test")
                .setExpiration(new Date(System.currentTimeMillis()+time))
                .setId(UUID.randomUUID().toString())
                //signature
                .signWith(SignatureAlgorithm.HS256,signature)
                .compact();
        System.out.println(jwtToken);
    }

    @org.junit.Test
    public void parse(){
        String token ="eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9.eyJ1c2VybmFtZSI6InRvbSIsInJvbGUiOiJhZG1pbiIsInN1YiI6ImFkbWluLXRlc3QiLCJleHAiOjE2NTg4MjMyODEsImp0aSI6ImE1Y2M3Y2IzLTM4NTItNGJmYS05NjAyLTllYjdjNTY2MjY5NCJ9.WOP5_VomcD_Ds1fgRlydAGPWIHBWtoiPqPJLxR93Q6o";
        JwtParser jwtParser = Jwts.parser();
        Jws<Claims> claimsJws = jwtParser.setSigningKey(signature).parseClaimsJws(token);
        Claims claims = claimsJws.getBody();
        System.out.println(claims.get("username"));
        System.out.println(claims.get("role"));
        System.out.println(claims.getId());
        System.out.println(claims.getSubject());
        System.out.println(claims.getExpiration());
    }
}

The results of the first and second tests are ：

eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9.eyJ1c2VybmFtZSI6InRvbSIsInJvbGUiOiJhZG1

pbiIsInN1YiI6ImFkbWluLXRlc3QiLCJleHAiOjE2NTg4MjMyODEsImp0aSI6ImE1Y2M3Y2IzL

TM4NTItNGJmYS05NjAyLTllYjdjNTY2MjY5NCJ9.WOP5_VomcD_Ds1fgRlydAGPWIHBWto

iPqPJLxR93Q6o