// 只能通过post方法来请求
@RequestMapping(value="items",method={RequestMethod.POST})

@RequestMapping("/requestJson")
public @ResponseBody ItemsCustom requestJson(@RequestBody ItemsCustom itemsCustom){
    // do something...
    
    return itemsCustom;	
}

// 返回的是json，输入的是key/value格式
@RequestMapping("/responseJson")
public @ResponseBody ItemsCustom responseJson(ItemsCustom itemsCustom){
    // do something...
    return itemsCustom;
}

package com.hundsun.shiro.JsonTest;
/**
 * user实体类
 * 
 * @author zeewane
 * @date 2016年9月21日 下午3:40:41
 */
public class User {
	private Long id;
	private String name;
	public Long getId() {
		return id;
	}
	public void setId(Long id) {
		this.id = id;
	}
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
}

package com.hundsun.shiro.JsonTest;
import java.util.List;
import java.util.ArrayList;
/**
 * group的实体类
 * 
 * @author zeewane
 * @date 2016年9月21日 下午3:42:05
 */
public class Group {
	private Long id;
	private String name;
	private List<User> users = new ArrayList<User>();
	public Long getId() {
		return id;
	}
	public void setId(Long id) {
		this.id = id;
	}
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	public List<User> getUsers() {
		return users;
	}
	public void setUsers(List<User> users) {
		this.users = users;
	}
}

package com.hundsun.shiro.JsonTest;
import com.alibaba.fastjson.JSON;
/**
 * fastjson的测试类，java对象和json格式之间的互转
 * 
 * @author zeewane
 * @date 2016年9月21日 下午3:47:20
 */
public class Test1 {
	public static void main(String[] args) {
		Group group = new Group();
		group.setId(0L);
		group.setName("admin");
		User guestUser = new User();
		guestUser.setId(2L);
		guestUser.setName("guest");
		User rootUser = new User();
		rootUser.setId(3L);
		rootUser.setName("root");
		group.getUsers().add(guestUser);
		group.getUsers().add(rootUser);
		// 将java对象转换成json
		String jsonString = JSON.toJSONString(group);
		System.out.println(jsonString);
		// 将json重新转换为java对象
		Group group2 = JSON.parseObject(jsonString, Group.class);
		System.out.println(group2.getName());
		for (User user : group2.getUsers()) {
			System.out.println(user.getId() + ":" + user.getName());
		}
	}
}
// output
{"id":0,"name":"admin","users":[{"id":2,"name":"guest"},{"id":3,"name":"root"}]}
admin
2:guest
3:root

// isPermitted里面传入的是权限标识符
subject.isPermitted("user:create:1");

// String类型的权限标识符
public boolean isPermitted(String permission) {
    return hasPrincipals() && securityManager.isPermitted(getPrincipals(), permission);
}
// 权限
public boolean isPermitted(Permission permission) {
    return hasPrincipals() && securityManager.isPermitted(getPrincipals(), permission);
}
// 是否有用户凭证信息，也就是用户是否存在的意思
protected boolean hasPrincipals() {
    return !CollectionUtils.isEmpty(getPrincipals());
}
// 返回主身份信息吗？只返回了集合中的第一个
public PrincipalCollection getPrincipals() {
    List<PrincipalCollection> runAsPrincipals = getRunAsPrincipalsStack();
    return CollectionUtils.isEmpty(runAsPrincipals) ? this.principals : runAsPrincipals.get(0);
}
// 从session中获取用户的身份凭证信息
@SuppressWarnings("unchecked")
private List<PrincipalCollection> getRunAsPrincipalsStack() {
    Session session = getSession(false);
    if (session != null) {
        return (List<PrincipalCollection>) session.getAttribute(RUN_AS_PRINCIPALS_SESSION_KEY);
    }
    return null;
}

private Authorizer authorizer;
// 构造函数中就new了一个ModularRealmAuthorizer
public AuthorizingSecurityManager() {
    super();
    this.authorizer = new ModularRealmAuthorizer();
}
public boolean isPermitted(PrincipalCollection principals, String permissionString) {
    return this.authorizer.isPermitted(principals, permissionString);
}
public boolean isPermitted(PrincipalCollection principals, Permission permission) {
    return this.authorizer.isPermitted(principals, permission);
}

public boolean isPermitted(PrincipalCollection principals, String permission) {
    assertRealmsConfigured();
    for (Realm realm : getRealms()) {
        if (!(realm instanceof Authorizer)) continue;
        if (((Authorizer) realm).isPermitted(principals, permission)) {
            return true;
        }
    }
    return false;
}
public boolean isPermitted(PrincipalCollection principals, Permission permission) {
    assertRealmsConfigured();
    for (Realm realm : getRealms()) {
        if (!(realm instanceof Authorizer)) continue;
        // 调用realm来进行授权的查询，只要一个满足就返回true
        if (((Authorizer) realm).isPermitted(principals, permission)) {
            return true;
        }
    }
    return false;
}

public boolean isPermitted(PrincipalCollection principals, String permission) {
    Permission p = getPermissionResolver().resolvePermission(permission);
    return isPermitted(principals, p);
}
public boolean isPermitted(PrincipalCollection principals, Permission permission) {
    // 这就是在自定义的realm里override的方法
    AuthorizationInfo info = getAuthorizationInfo(principals);
    // 会从info中获取信息
    return isPermitted(permission, info);
}
private boolean isPermitted(Permission permission, AuthorizationInfo info) {
    // 取出所有的权限信息然后遍历寻找
    Collection<Permission> perms = getPermissions(info);
    if (perms != null && !perms.isEmpty()) {
        for (Permission perm : perms) {
            if (perm.implies(permission)) {
                return true;
            }
        }
    }
    return false;
}

// 执行认证的提交
try {
    subject.login(token);
} catch (AuthenticationException e) {
    // TODO Auto-generated catch block
    e.printStackTrace();
}

public class DelegatingSubject implements Subject {
}

public void login(AuthenticationToken token) throws AuthenticationException {
    clearRunAsIdentitiesInternal();
    // subject是返回的已经认证处理过的，根据token去查询出来的subject对象
    Subject subject = securityManager.login(this, token);
    // 用户的身份凭证信息
    PrincipalCollection principals;
    String host = null;
    // 把subject中获取到的凭证信息放进去
    if (subject instanceof DelegatingSubject) {
        DelegatingSubject delegating = (DelegatingSubject) subject;
        //we have to do this in case there are assumed identities - we don't want to lose the 'real' principals:
        principals = delegating.principals;
        host = delegating.host;
    } else {
        principals = subject.getPrincipals();
    }
    // 如果凭证信息为空，就是没有有效的用户认证信息返回，就抛出异常
    if (principals == null || principals.isEmpty()) {
        String msg = "Principals returned from securityManager.login( token ) returned a null or " +
                "empty value.  This value must be non null and populated with one or more elements.";
        throw new IllegalStateException(msg);
    }
    
    // 有合法的凭证信息，就全部塞到调用login的那个subject中，完成副作用
    this.principals = principals;
    this.authenticated = true;
    if (token instanceof HostAuthenticationToken) {
        host = ((HostAuthenticationToken) token).getHost();
    }
    if (host != null) {
        this.host = host;
    }
    Session session = subject.getSession(false);
    if (session != null) {
        this.session = decorate(session);
    } else {
        this.session = null;
    }
}

public Subject login(Subject subject, AuthenticationToken token) throws AuthenticationException {
    AuthenticationInfo info;
    try {
        // 根据token去进行认证，返回一个认证信息，authenticationInfo
        info = authenticate(token);
    } catch (AuthenticationException ae) {
        try {
            // 认证失败就抛出认证失败的异常
            onFailedLogin(token, ae, subject);
        } catch (Exception e) {
            if (log.isInfoEnabled()) {
                log.info("onFailedLogin method threw an " +
                        "exception.  Logging and propagating original AuthenticationException.", e);
            }
        }
        throw ae; //propagate
    }
    // 如果到这步，说明认证成功，把认证信息、令牌等全部组装成一个新的subject，返回这个已经通过认证的，已登录的subject
    Subject loggedIn = createSubject(token, info, subject);
    onSuccessfulLogin(token, info, loggedIn);
    return loggedIn;
}

public AuthenticationInfo authenticate(AuthenticationToken token) throws AuthenticationException {
    // 值得一提的是这个authenticator是默认的new的一个ModularRealmAuthenticator
    return this.authenticator.authenticate(token);
}

public final AuthenticationInfo authenticate(AuthenticationToken token) throws AuthenticationException {
    if (token == null) {
        throw new IllegalArgumentException("Method argumet (authentication token) cannot be null.");
    }
    log.trace("Authentication attempt received for token [{}]", token);
    AuthenticationInfo info;
    try {
        // 进行认证，认证信息放到info中，否则抛异常
        info = doAuthenticate(token);
        if (info == null) {
            String msg = "No account information found for authentication token [" + token + "] by this " +
                    "Authenticator instance.  Please check that it is configured correctly.";
            throw new AuthenticationException(msg);
        }
    } catch (Throwable t) {
        AuthenticationException ae = null;
        if (t instanceof AuthenticationException) {
            ae = (AuthenticationException) t;
        }
        if (ae == null) {
            //Exception thrown was not an expected AuthenticationException.  Therefore it is probably a little more
            //severe or unexpected.  So, wrap in an AuthenticationException, log to warn, and propagate:
            String msg = "Authentication failed for token submission [" + token + "].  Possible unexpected " +
                    "error? (Typical or expected login exceptions should extend from AuthenticationException).";
            ae = new AuthenticationException(msg, t);
        }
        try {
            notifyFailure(token, ae);
        } catch (Throwable t2) {
            if (log.isWarnEnabled()) {
                String msg = "Unable to send notification for failed authentication attempt - listener error?.  " +
                        "Please check your AuthenticationListener implementation(s).  Logging sending exception " +
                        "and propagating original AuthenticationException instead...";
                log.warn(msg, t2);
            }
        }
        throw ae;
    }
    log.debug("Authentication successful for token [{}].  Returned account [{}]", token, info);
    notifySuccess(token, info);
    return info;
}

protected AuthenticationInfo doAuthenticate(AuthenticationToken authenticationToken) throws AuthenticationException {
    assertRealmsConfigured();
    Collection<Realm> realms = getRealms();
    // 判断多个realm还是单个realm
    if (realms.size() == 1) {
        return doSingleRealmAuthentication(realms.iterator().next(), authenticationToken);
    } else {
        return doMultiRealmAuthentication(realms, authenticationToken);
    }
}
// 单个realm进行认证 
protected AuthenticationInfo doSingleRealmAuthentication(Realm realm, AuthenticationToken token) {
    if (!realm.supports(token)) {
        String msg = "Realm [" + realm + "] does not support authentication token [" +
                token + "].  Please ensure that the appropriate Realm implementation is " +
                "configured correctly or that the realm accepts AuthenticationTokens of this type.";
        throw new UnsupportedTokenException(msg);
    }
    // 这个get方法就是我们自定义realm的时候override的方法
    AuthenticationInfo info = realm.getAuthenticationInfo(token);
    if (info == null) {
        String msg = "Realm [" + realm + "] was unable to find account data for the " +
                "submitted AuthenticationToken [" + token + "].";
        throw new UnknownAccountException(msg);
    }
    return info;
}

// 配置认证策略
DefaultSecurityManager securityManager = new DefaultSecurityManager();
ModularRealmAuthenticator authenticator = new ModularRealmAuthenticator();
authenticator.setAuthenticationStrategy(new AllSuccessfulStrategy());
securityManager.setAuthenticator(authenticator);