第七章 企业项目开发-本地缓存guava cache

        <!-- guava cache -->        <dependency>            <groupId>com.google.guava</groupId>            <artifactId>guava</artifactId>            <version>14.0.1</version>        </dependency>

package com.xxx.mapper.userManagement;import java.util.List;import org.apache.ibatis.annotations.Insert;import org.apache.ibatis.annotations.Param;import org.apache.ibatis.annotations.Result;import org.apache.ibatis.annotations.Results;import org.apache.ibatis.annotations.Select;import com.xxx.model.userManagement.Admin;/** * 管理员Mapper */public interface AdminMapper {        /**************注解**************/    @Insert("INSERT INTO userinfo(username, password) VALUES(#{username},#{password})")    public int insertAdmin(Admin admin);    @Select("SELECT * FROM userinfo WHERE username = #{username} AND password = #{password}")    @Results(value = {             @Result(id = true, column = "id", property = "id"),            @Result(column = "username", property = "username"),            @Result(column = "password", property = "password") })    public Admin selectAdmin(@Param("username") String username,                             @Param("password") String password);        /***************xml**************/    /**     * 条件不定式查询     * 我们这里使用@Param指定参数，这样的话，在AdminMapper.xml中就不用再使用parameterType属性了；否则得写parameterType属性     */    public List<Admin> getAdminByConditions(@Param("username")String username,                                            @Param("password")String password,                                             @Param("start")int start,                                             @Param("limit")int limit);        /**     * 返回主键     */    public int insertAdminWithBackId(Admin admin);        /****************guava cache*****************/    @Select("SELECT * FROM userinfo WHERE username = #{username}")    @Results(value = {             @Result(id = true, column = "id", property = "id"),            @Result(column = "username", property = "username"),            @Result(column = "password", property = "password") })    public List<Admin> getUserByName(@Param("username") String username);}

package com.xxx.dao.userManagement;import java.util.List;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.stereotype.Repository;import com.xxx.mapper.userManagement.AdminMapper;import com.xxx.model.userManagement.Admin;/** * 管理员DAO */@Repositorypublic class AdminDao {    @Autowired    private AdminMapper adminMapper;    /***************注解*****************/    public boolean register(Admin admin){        return adminMapper.insertAdmin(admin)==1?true:false;    }        public Admin login(String username ,String password){        return adminMapper.selectAdmin(username, password);    }    /****************xml******************/    public List<Admin> findAdmin(String username, String password, int start, int limit){        return adminMapper.getAdminByConditions(username, password, start, limit);    }        public int insertAdminWithBackId(Admin admin){        return adminMapper.insertAdminWithBackId(admin);    }    /******************guava cache********************/    public List<Admin> getUserByName(String username){        return adminMapper.getUserByName(username);    }}

package com.xxx.service.userManagement;import java.util.List;import java.util.concurrent.ExecutionException;import java.util.concurrent.TimeUnit;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.stereotype.Service;import com.google.common.cache.CacheBuilder;import com.google.common.cache.CacheLoader;import com.google.common.cache.LoadingCache;import com.xxx.dao.userManagement.AdminDao;import com.xxx.model.userManagement.Admin;import com.xxx.vo.userManagement.AdminCacheKey;/** * 管理员service */@Servicepublic class AdminService {    @Autowired    private AdminDao adminDao;    public boolean register(Admin admin) {        return adminDao.register(admin);    }    public Admin login(String username, String password) {        return adminDao.login(username, password);    }    /*********** 以下方法是为了测试mybatis中使用xml **********/    public List<Admin> findAdmin(String username,                                  String password,                                  int start,                                 int limit) {        return adminDao.findAdmin(username, password, start, limit);    }    public Admin insertAdminWithBackId(Admin admin) {        int record = adminDao.insertAdminWithBackId(admin);        if (record == 1) {            return admin;// 这时的admin已经被赋予主键了        }        return null;    }    /************************ guava cache *************************/    /************单条件的查询，key为String***********/    public List<Admin> findByUsername(String username) {        List<Admin> adminList = null;        try {            adminList = adminListCache.get(username);        } catch (ExecutionException e) {            e.printStackTrace();        }        return adminList;    }    LoadingCache<String, List<Admin>> adminListCache = CacheBuilder.newBuilder()            .expireAfterWrite(20, TimeUnit.MINUTES)// 缓存20分钟            .maximumSize(1000)// 最多缓存1000个对象            .build(new CacheLoader<String, List<Admin>>() {                public List<Admin> load(String username) throws Exception {                    return adminDao.getUserByName(username);                }            });    /************多条件的查询，key为Object（封装了多个条件的VO类）***********/    public List<Admin> findAdminList(String username,                                      String password,                                     int start,                                      int limit) {        /*         * 注意：         * 如果以一个新建的对象做为key的话，因为每次都是新建一个对象，所以这样的话，实际上每次访问key都是不同的，即每次访问都是重新进行缓存;         * 但是实际上，我们想要根据对象的属性来判断对象是否相等，只需要根据这些属性重写对象的hashCode与equals方法即可，         * 所以重写了AdminCacheKey类的hashCode和equals方法，这样，每次访问的话，就会以每个条件是否相等来判断对象（即key）是否相等了，这一块儿的缓存就会起作用了         */        AdminCacheKey cacheKey = new AdminCacheKey(username,                                                    password,                                                    start,                                                   limit);        List<Admin> adminList = null;        try {            System.out.println(cacheKey);            adminList = adminsCache.get(cacheKey);        } catch (ExecutionException e) {            e.printStackTrace();        }        return adminList;    }    LoadingCache<AdminCacheKey, List<Admin>> adminsCache = CacheBuilder.newBuilder()            .expireAfterWrite(60, TimeUnit.MINUTES) // 缓存项在给定时间内（60min）没有被写访问（创建或覆盖），则回收            .maximumSize(100) // 最多缓存100项            .build(new CacheLoader<AdminCacheKey, List<Admin>>() {                public List<Admin> load(AdminCacheKey key) throws Exception {                    return adminDao.findAdmin(key.getUsername(),                                              key.getPassword(),                                               key.getStart(),                                               key.getLimit());                }            });}

package com.xxx.vo.userManagement;/** * guava cache的key */public class AdminCacheKey {    private String username;    private String password;    private int start;    private int limit;    public AdminCacheKey() {    }    public AdminCacheKey(String username, String password, int start, int limit) {        this.username = username;        this.password = password;        this.start = start;        this.limit = limit;    }    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;    }    public int getStart() {        return start;    }    public void setStart(int start) {        this.start = start;    }    public int getLimit() {        return limit;    }    public void setLimit(int limit) {        this.limit = limit;    }    @Override    public int hashCode() {        final int prime = 31;        int result = 1;        result = prime * result + limit;        result = prime * result                + ((password == null) ? 0 : password.hashCode());        result = prime * result + start;        result = prime * result                + ((username == null) ? 0 : username.hashCode());        return result;    }    @Override    public boolean equals(Object obj) {        if (this == obj)            return true;        if (obj == null)            return false;        if (getClass() != obj.getClass())            return false;        AdminCacheKey other = (AdminCacheKey) obj;        if (limit != other.limit)            return false;        if (password == null) {            if (other.password != null)                return false;        } else if (!password.equals(other.password))            return false;        if (start != other.start)            return false;        if (username == null) {            if (other.username != null)                return false;        } else if (!username.equals(other.username))            return false;        return true;    }}

package com.xxx.web.admin;import java.util.List;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import javax.servlet.http.HttpSession;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.stereotype.Controller;import org.springframework.web.bind.annotation.RequestMapping;import org.springframework.web.bind.annotation.RequestParam;import org.springframework.web.bind.annotation.ResponseBody;import org.springframework.web.servlet.ModelAndView;import com.xxx.model.userManagement.Admin;import com.xxx.service.userManagement.AdminService;import com.xxx.util.admin.AdminCookieUtil;/** * adminController */@Controller@RequestMapping("/admin")public class AdminController {        @Autowired    private AdminService adminService;        /**     * 管理员注册     */    @ResponseBody    @RequestMapping("/register")    public boolean register(@RequestParam("username") String username,                            @RequestParam("password") String password){        Admin admin = new Admin();        admin.setUsername(username);        admin.setPassword(password);                boolean isRegisterSuccess = adminService.register(admin);                return isRegisterSuccess;    }        /**     * 管理员登录     */    @RequestMapping("/login")    public ModelAndView login(@RequestParam("username") String username,                              @RequestParam("password") String password,                              HttpServletResponse response,                              HttpSession session){                        Admin admin = adminService.login(username, password);                ModelAndView modelAndView = new ModelAndView();        if(admin == null){            modelAndView.addObject("message", "用户不存在或者密码错误！请重新输入");            modelAndView.setViewName("error");        }else{            modelAndView.addObject("admin", admin);            modelAndView.setViewName("userinfo");            /*             * 这为什么不直接传一个username，而传了一个admin，             * 是因为在实际开发中，你传过去的信息可能不只是username，还有用户手机号、地址等等             */            //使用cookie            AdminCookieUtil.addLoginCookie(admin, response);            //使用session            //session.setAttribute("adminSession", admin);        }                return modelAndView;    }        /*****************************mybatis xml方式解决的问题*******************************/    /**     * 根据username或password查找List<Admin>     */    @ResponseBody    @RequestMapping("/findAdmin")    public List<Admin> findAdmin(@RequestParam(value="username",required=false) String username,                                    @RequestParam(value="password",required=false) String password,                                    @RequestParam("start") int start,                                    @RequestParam("limit") int limit,                                    HttpServletRequest request,                                    HttpSession session){        Admin admin = AdminCookieUtil.getLoginCookie(request);        //Admin admin = (Admin) session.getAttribute("adminSession");                if(admin == null){//未登录            return null;        }        System.out.println(admin.toJson());        List<Admin> adminList = adminService.findAdmin(username, password, start, limit);        return adminList;    }        /**     * 插入一个用户并返回主键     * 注意：get请求也会自动装配（即将前台传入的username和password传入admin）     */    @ResponseBody    @RequestMapping("/insert")    public Admin insertAdminWithBackId(Admin admin){        return adminService.insertAdminWithBackId(admin);    }    /*************************guava cache******************************/    /**     * 根据username查找List<Admin>     */    @ResponseBody    @RequestMapping("/findAdminByUsername")    public List<Admin> findAdminByUserName(@RequestParam(value="username") String username){                List<Admin> adminList = adminService.findByUsername(username);        return adminList;    }        @ResponseBody    @RequestMapping("/findAdminList")    public List<Admin> findAdminList(@RequestParam(value="username") String username,                                         @RequestParam(value="password",required=false) String password,                                         @RequestParam("start") int start,                                         @RequestParam("limit") int limit){                List<Admin> adminList = adminService.findAdminList(username, password, start, limit);        return adminList;    }}