学习shiro第二天

昨天讲了shiro的认证流程以及代码实现，今天将对这个进行扩展。

因为我们的测试数据是shiro.ini文件中配置的静态数据，但实际上数据应该从数据库中查询出来才合理，因此我们今天讲讲JdbcRealm的使用。

本次需要的jar包如下：

commons-beanutils-1.9.3.jar
commons-logging-1.2.jar
jcl-over-slf4j-1.7.12.jar
log4j-1.2.16.jar
shiro-all-1.4.1.jar
slf4j-api-1.7.25.jar
slf4j-log4j12-1.6.4.jar
mysql-connector-java-5.1.47.jar
mchange-commons-java-0.2.11.jar
c3p0-0.9.5.2.jar

IniSecurityManagerFactory部分源码：

    public static final String MAIN_SECTION_NAME = "main";

    public static final String SECURITY_MANAGER_NAME = "securityManager";
    public static final String INI_REALM_NAME = "iniRealm";
   
    ......
    protected Map<String, ?> createDefaults(Ini ini, Ini.Section mainSection) {
        Map<String, Object> defaults = new LinkedHashMap<String, Object>();

        SecurityManager securityManager = createDefaultInstance();
        defaults.put(SECURITY_MANAGER_NAME, securityManager);

        if (shouldImplicitlyCreateRealm(ini)) {
            Realm realm = createRealm(ini);
            if (realm != null) {
                defaults.put(INI_REALM_NAME, realm);
            }
        }
    ......

从这段源码可以看到，IniSecurityManagerFactory在初始化时默认将iniRealm设置到SecurityManager中，除非我们自己设置SecurityManager使用哪个realm，它获取判断realm不为空，才将我们设置的realm设置到SecurityManager中，因此我们要在shiro.ini中配置新的realm即JdbcRealm。

JdbcRealm部分源码：

/**
     * The default query used to retrieve account data for the user.
     */
    protected static final String DEFAULT_AUTHENTICATION_QUERY = "select password from users where username = ?";
    
    /**
     * The default query used to retrieve account data for the user when {@link #saltStyle} is COLUMN.
     */
    protected static final String DEFAULT_SALTED_AUTHENTICATION_QUERY = "select password, password_salt from users where username = ?";

    /**
     * The default query used to retrieve the roles that apply to a user.
     */
    protected static final String DEFAULT_USER_ROLES_QUERY = "select role_name from user_roles where username = ?";

    /**
     * The default query used to retrieve permissions that apply to a particular role.
     */
    protected static final String DEFAULT_PERMISSIONS_QUERY = "select permission from roles_permissions where role_name = ?";

......
 public void setDataSource(DataSource dataSource) {
        this.dataSource = dataSource;
    }
......
 protected AuthenticationInfo doGetAuthenticationInfo(AuthenticationToken token) throws AuthenticationException {

        UsernamePasswordToken upToken = (UsernamePasswordToken) token;
        String username = upToken.getUsername();

        // Null username is invalid
        if (username == null) {
            throw new AccountException("Null usernames are not allowed by this realm.");
        }

        Connection conn = null;
        SimpleAuthenticationInfo info = null;
        try {
            conn = dataSource.getConnection();

            String password = null;
            String salt = null;
            switch (saltStyle) {
            case NO_SALT:
                password = getPasswordForUser(conn, username)[0];
                break;
            case CRYPT:
                // TODO: separate password and hash from getPasswordForUser[0]
                throw new ConfigurationException("Not implemented yet");
                //break;
            case COLUMN:
                String[] queryResults = getPasswordForUser(conn, username);
                password = queryResults[0];
                salt = queryResults[1];
                break;
            case EXTERNAL:
                password = getPasswordForUser(conn, username)[0];
                salt = getSaltForUser(username);
            }

            if (password == null) {
                throw new UnknownAccountException("No account found for user [" + username + "]");
            }

            info = new SimpleAuthenticationInfo(username, password.toCharArray(), getName());
            
            if (salt != null) {
                info.setCredentialsSalt(ByteSource.Util.bytes(salt));
            }

        } catch (SQLException e) {
            final String message = "There was a SQL error while authenticating user [" + username + "]";
            if (log.isErrorEnabled()) {
                log.error(message, e);
            }

            // Rethrow any SQL errors as an authentication exception
            throw new AuthenticationException(message, e);
        } finally {
            JdbcUtils.closeConnection(conn);
        }

        return info;
    }

从JdbcRealm的源码中我们看到了许多sql语句，都是从表users中去查询字段username、password、password_salt等等，而且源码中还出现了dataSource，而这个dataSource是需要我们set进去的，因此要使用JdbcRealm，我们必须在数据库创建表users以及对应的字段，还需要为JdbcRealm注入dataSource。下面我们开始配置shiro.ini文件。

shiro.ini文件：

[main]
dataSource=com.mchange.v2.c3p0.ComboPooledDataSource
dataSource.driverClass=com.mysql.jdbc.Driver
dataSource.jdbcUrl=jdbc:mysql://localhost:3306/test
dataSource.user=root
dataSource.password=root
myRealm=org.apache.shiro.realm.jdbc.JdbcRealm
myRealm.dataSource=$dataSource
securityManager.realm=$myRealm

差点忘了说，在shiro.ini文件中，有许多模块组成，比如昨天的[users]用来存放静态数据，和上面的[main]是用来配置SecurityManager和它所需要的依赖组件如realm的模块，当然还有配置用户角色的模块[role],我们这里就不多讲了，留到授权模块再将。

了解了[main]的应用，我们再看看上面的配置，首先我们配置了一个dataSource（这里配的是数据源c3p0,记得导包哦），包括配置它的数据库驱动、Url、数据库登录名以及密码，然后配了一个myRealm指向了JdbcRealm,再将上面的dataSource设置到myRealm中从而实现了dataSource的注入（这里的$代表注入，跟spring的注入异曲同工），再将这个myRealm设置成SecurityManager的默认realm从而完成配置。

配置完成了，接下来我们还要在数据库中创建users表：

如图，在test数据库下创建users表，其中必须包含JdbcRealm类中的sql语句中出现的字段，这里我们设置了三个。

创建完表，我们开始编码，流程其实跟第一天的差不多：

package test_JdbcRealm;

import org.apache.shiro.SecurityUtils;
import org.apache.shiro.authc.AuthenticationException;
import org.apache.shiro.authc.UsernamePasswordToken;
import org.apache.shiro.config.IniSecurityManagerFactory;
import org.apache.shiro.mgt.SecurityManager;
import org.apache.shiro.subject.Subject;
import org.apache.shiro.util.Factory;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class TestJdbcRealm {

    private static final Logger logger = LoggerFactory.getLogger(TestJdbcRealm.class);
    
    public static void main(String[] args) {
        //1.创建securityManager工厂
        Factory<SecurityManager> factory = new IniSecurityManagerFactory("classpath:shiro.ini");
        //2.获取securityManager实例
        SecurityManager securityManager = factory.getInstance();
        //3.将SecurityManager实例设置到SecurityUtils工具类中
        SecurityUtils.setSecurityManager(securityManager);
        //4。创建Subject实例
        Subject subject = SecurityUtils.getSubject();
        //5.获取token,模拟用户登陆
        UsernamePasswordToken token = new UsernamePasswordToken("zhangsan", "123456");
        try {
            //6.认证token
            subject.login(token);
            if(subject.isAuthenticated()) {
                logger.info("登陆成功");
            }
        } catch (AuthenticationException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
            logger.error("用户名或密码错误，登陆失败");
        }
    }
}

2019-07-25 23:30:43,705 INFO [com.mchange.v2.log.MLog] - MLog clients using slf4j logging. 
2019-07-25 23:30:44,102 INFO [com.mchange.v2.c3p0.C3P0Registry] - Initializing c3p0-0.9.5.2 [built 08-December-2015 22:06:04 -0800; debug? true; trace: 10] 
2019-07-25 23:30:44,211 INFO [org.apache.shiro.config.IniSecurityManagerFactory] - Realms have been explicitly set on the SecurityManager instance - auto-setting of realms will not occur. 
2019-07-25 23:30:44,233 INFO [com.mchange.v2.c3p0.impl.AbstractPoolBackedDataSource] - Initializing c3p0 pool... com.mchange.v2.c3p0.ComboPooledDataSource [ acquireIncrement -> 3, acquireRetryAttempts -> 30, acquireRetryDelay -> 1000, autoCommitOnClose -> false, automaticTestTable -> null, breakAfterAcquireFailure -> false, checkoutTimeout -> 0, connectionCustomizerClassName -> null, connectionTesterClassName -> com.mchange.v2.c3p0.impl.DefaultConnectionTester, contextClassLoaderSource -> caller, dataSourceName -> 2zm2h8a4bl36b813yacsm|7e0ea639, debugUnreturnedConnectionStackTraces -> false, description -> null, driverClass -> com.mysql.jdbc.Driver, extensions -> {}, factoryClassLocation -> null, forceIgnoreUnresolvedTransactions -> false, forceSynchronousCheckins -> false, forceUseNamedDriverClass -> false, identityToken -> 2zm2h8a4bl36b813yacsm|7e0ea639, idleConnectionTestPeriod -> 0, initialPoolSize -> 3, jdbcUrl -> jdbc:mysql://localhost:3306/test, maxAdministrativeTaskTime -> 0, maxConnectionAge -> 0, maxIdleTime -> 0, maxIdleTimeExcessConnections -> 0, maxPoolSize -> 15, maxStatements -> 0, maxStatementsPerConnection -> 0, minPoolSize -> 3, numHelperThreads -> 3, preferredTestQuery -> null, privilegeSpawnedThreads -> false, properties -> {user=******, password=******}, propertyCycle -> 0, statementCacheNumDeferredCloseThreads -> 0, testConnectionOnCheckin -> false, testConnectionOnCheckout -> false, unreturnedConnectionTimeout -> 0, userOverrides -> {}, usesTraditionalReflectiveProxies -> false ] 
2019-07-25 23:30:44,525 INFO [org.apache.shiro.session.mgt.AbstractValidatingSessionManager] - Enabling session validation scheduler... 
2019-07-25 23:30:44,537 INFO [test_JdbcRealm.TestJdbcRealm] - 登陆成功 

同样是这几个步骤，但是在加载配置文件生成SecurityManager的实例却是不一样的，因为我们在配置文件中配置了SecurityManager的默认realm为JdbcRealm，因此在subjec.login(token)认证时，最终会通过JdbcRealm的认证方法从数据库中查出用户数据来进行比对认证！

总结：

1.在使用一个类的时候，我们需要通过源码去了解它需要什么，然后才能有目的地进行配置，就像JdbcRealm这个类，它需要一张表和数据源来实现从数据库查询出数据进行认证；

2.shiro.ini包含多个组成部分，如[main],[users],[role]还有[url],我们需要了解各个部分地主要功能和作用；

3.从上面地例子我们可以得知，SecurityManager使用地realm是可以进行配置的！！因此也就说明了我们可以自定义realm来实现认证和授权逻辑！这部分后续我学习到了将会进行分享。

以上是我今天学习shiro所得，大家如果有什么补充或者建议，麻烦在评论区留言，谢谢！