Java 集成LMDB

偏执的太偏执、 2023-03-13 06:39 116阅读 0赞

## 0、pom.xml依赖 ##

<dependency>
 			<groupId>org.lmdbjava</groupId>
 			<artifactId>lmdbjava</artifactId>
 			<version>0.7.0</version>
 		</dependency>

## 1、application.properties配置： ##

lmdb.path=E:\\lmdb
    #单位为MB
    lmdb.max.size=256
    lmdb.database.count=10

## 2、LmdbServier 工具类 ##

import lombok.extern.slf4j.Slf4j;
 import org.lmdbjava.*;
 import org.springframework.stereotype.Service;
 import javax.annotation.PostConstruct;
 import java.io.File;
 import java.nio.ByteBuffer;
 import java.nio.charset.StandardCharsets;
 import java.util.HashMap;
 import java.util.Map;
 import static java.lang.Integer.BYTES;
 import static java.nio.ByteBuffer.allocateDirect;
 import static org.lmdbjava.ByteBufferProxy.PROXY_OPTIMAL;
 import static org.lmdbjava.DbiFlags.MDB_CREATE;
 import static org.lmdbjava.Env.create;
 
 /** * Lmdb操作工具类 * * @author jack * @version 1.0 * @CreateDate 2020年5月11日 */
 @Slf4j
 @Service
 public class LmdbService { 
 
 /** * lmdb path */
 @Value("${lmdb.path}")
 private String lmdbPath;
 
 /** * env */
 private Env<ByteBuffer> env;
 
 /** * lmdb max size */
 @Value("${lmdb.max.size}")
 private int lmdbMaxSize;
 
 /** * lmdb库的数量 */
 @Value("${lmdb.database.count}")
 private int lmdbDatabaseCount;
 
 /** * Description: 初始化操作 * @author jack * @version 1.0 * @CreateDate 2020年5月11日 */
 @PostConstruct
 private void init(){ 
 try { 
 final File path = new File(lmdbPath);
 env = create(PROXY_OPTIMAL)
 .setMapSize(lmdbMaxSize * 1024 * 1024)
 .setMaxDbs(lmdbDatabaseCount)
 .setMaxReaders(lmdbDatabaseCount*2)
 .open(path);
 log.info("初始化Lmdb成功......");
 } catch (Exception e) { 
 throw new LmdbException("IO failure", e);
 }
 }
 
 /** * Description: 向库中插入数据 * @param dbName dbname * @param key value 数据 * @author jack * @version 1.0 * @CreateDate 2020年5月11日 */
 public void putValueToDb(String dbName, String key,String value) { 
 final Dbi<ByteBuffer> db = env.openDbi(dbName, MDB_CREATE);
 try (Txn<ByteBuffer> txn = env.txnWrite()) { 
 final Cursor<ByteBuffer> c = db.openCursor(txn);
 c.put(bb(key), bb(value));
 c.close();
 txn.commit();
 }
 
 }
 
 /** * Description: 根据指定的key获取数据 * @param dbName dbname * @param key key * @author jack * @version 1.0 * @CreateDate 2020年5月11日 */
 public String getValueByKey(String dbName, String key) { 
 
 final Dbi<ByteBuffer> db = env.openDbi(dbName, MDB_CREATE);
 final Cursor<ByteBuffer> c;
 String value ="";
 try (Txn<ByteBuffer> txn = env.txnRead()) { 
 c = db.openCursor(txn);
 c.get(bb(key),GetOp.MDB_SET_KEY);
 ByteBuffer byteBuffer = c.val();
 c.close();
 value = StandardCharsets.UTF_8.decode(byteBuffer).toString();
 }
 return value;
 }
 
 /** * Description: 获取库下所有的数据 * @param dbName dbname * @author jack * @version 1.0 * @CreateDate 2020年5月11日 */
 public Map<String, String> getAllValueByDbName(String dbName) { 
 final Dbi<ByteBuffer> db = env.openDbi(dbName, MDB_CREATE);
 Map<String, String> map = new HashMap<>();
 try (Txn<ByteBuffer> txn = env.txnRead()) { 
 Cursor<ByteBuffer> cursor = db.openCursor(txn);
 while (cursor.next()) { 
 ByteBuffer key = cursor.key();
 ByteBuffer val = cursor.val();
 byte[] k = new byte[key.capacity()];
 byte[] v = new byte[val.capacity()];
 key.get(k);
 val.get(v);
 map.put(new String(k,StandardCharsets.UTF_8), new String(v,StandardCharsets.UTF_8));
 }
 cursor.close();
 }
 return map;
 }
 
 /** * Description: 根据dbname获取该库下的数量 * @param dbName dbname * @author jack * @version 1.0 * @CreateDate 2020年5月11日 */
 public long getDbCount(String dbName) { 
 return getAllValueByDbName(dbName).size();
 }
 
 /** * 格式化 ByteBuffer * @param value * @author jack * @version 1.0 * @CreateDate 2020年5月11日 */
 static ByteBuffer bb(final int value) { 
 final ByteBuffer bb = allocateDirect(BYTES);
 bb.putInt(value).flip();
 return bb;
 }
 
 /** * 格式化 ByteBuffer * @param value * @author jack * @version 1.0 * @CreateDate 2020年5月11日 */
 static ByteBuffer bb(final String value) { 
 byte[] val = value.getBytes(StandardCharsets.UTF_8);
 final ByteBuffer bb = allocateDirect(val.length);
 bb.put(val).flip();
 return bb;
 }
 
 }

## 3、lmdb数据库名称枚举:LmdbNameEnum ##

主要用于：定义lmdb中的dbName

public enum LmdbNameEnum { 
    	//点位状态
    	PointStatus("pointStatus");
    
    	private String dbName;
    
    	LmdbNameEnum(String dbName) { 
    		this.dbName = dbName;
    	}
    
    	public String getDbName() { 
    		return dbName;
    	}
    
    	@Override
    	public String toString() { 
    		return "LmdbNameEnum{" + "dbName=" + dbName + '}';
    	}
    }

## 4、Demo测试:LmdbController ##

package com.jack.maintain.controller;
 
 import com.jack.framework.json.resp.BaseResp;
 import com.jack.maintain.cache.LmdbService;
 import com.jack.maintain.enums.LmdbNameEnum;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.stereotype.Controller;
 import org.springframework.web.bind.annotation.*;
 
 import java.util.Map;
 
 @Controller
 @RequestMapping(value = "/lmdb")
 public class LmdbController{ 
 
 @Autowired
 private LmdbService lmdbOperation;
 
 
 @RequestMapping(value = "setPoint/{point}",method = RequestMethod.GET)
 @ResponseBody
 public BaseResp setPoint(@PathVariable("point") String point){ 
 lmdbOperation.putValueToDb(LmdbNameEnum.PointStatus.getDbName(),point,point);
 return BaseResp.success("设值成功");
 }
 
 @RequestMapping(value = "getPoint/{point}",method = RequestMethod.GET)
 @ResponseBody
 public BaseResp getPoint(@PathVariable("point") String point){ 
 String val = lmdbOperation.getValueByKey(LmdbNameEnum.PointStatus.getDbName(),point);
 return BaseResp.success("成功",val);
 }
 
 @RequestMapping(value = "getPointCount",method = RequestMethod.GET)
 @ResponseBody
 public BaseResp getPointCount(){ 
 long count = lmdbOperation.getDbCount(LmdbNameEnum.PointStatus.getDbName());
 return BaseResp.success("成功",count);
 }
 
 @RequestMapping(value = "getPointList",method = RequestMethod.GET)
 @ResponseBody
 public BaseResp getDbVal(){ 
 Map<String,String> resultMap = lmdbOperation.getAllValueByDbName(LmdbNameEnum.PointStatus.getDbName());
 return BaseResp.success("成功",resultMap);
 }
 
 }

## 测试结果: ##

插入值：  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2ZhbmdjaGFvMjAxMQ_size_16_color_FFFFFF_t_70]  
获取值：  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2ZhbmdjaGFvMjAxMQ_size_16_color_FFFFFF_t_70 1]  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2ZhbmdjaGFvMjAxMQ_size_16_color_FFFFFF_t_70 2]  
配置文件中定义的lmdb数据路径：  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2ZhbmdjaGFvMjAxMQ_size_16_color_FFFFFF_t_70 3]

## 资源补全：（相关的公共方法类） ##

**BaseResp.java（接口统一返回封装类）**

import java.util.List;
 
 import com.jack.framework.json.JsonMsgUtil;
 import com.fasterxml.jackson.annotation.JsonView;
 
 import lombok.Data;
 import lombok.experimental.Accessors;
 
 /** * @Description: 基础返回类 * @date 2018年5月21日 下午9:28:00 */
 @Data
 @Accessors(chain = true)
 public class BaseResp { 
 
 	public interface DefaultJsonView { 
 	};
 
 	@JsonView(DefaultJsonView.class)
 	private boolean rs;
 
 	@JsonView(DefaultJsonView.class)
 	private int code;
 
 	@JsonView(DefaultJsonView.class)
 	private String msg;
 
 	@JsonView(DefaultJsonView.class)
 	private Object data;
 
 	@JsonView(DefaultJsonView.class)
 	private List<?> datas;
 
 	public BaseResp() { 
 		this(0);
 	}
 
 	public BaseResp(int code) { 
 		this.code = code;
 	}
 
 	public BaseResp(int code, String msg) { 
 		this.code = code;
 		this.msg = msg;
 	}
 
 	public String getMsg() { 
 		if (msg == null) { 
 			this.msg = JsonMsgUtil.getMsg(code);
 		}
 		if (this.msg == "") { 
 			this.msg = JsonMsgUtil.getMsg(9999);
 		}
 		return msg;
 	}
 
 	public boolean getRs() { 
 		rs = code == 0;
 		return rs;
 	}
 
 	public boolean isRs() { 
 		rs = code == 0;
 		return rs;
 	}
 
 	public static boolean isSuccess(BaseResp resp) { 
 		return resp.isRs();
 	}
 
 	/** * 功能描述：请求成功 * @param filePath */
 	public static BaseResp success(String msg) { 
 		BaseResp r = new BaseResp(0);
 		r.setMsg(msg);
 		return r;
 	}
 	//
 	public static BaseResp success(String msg, Object data) { 
 		BaseResp r = new BaseResp(0);
 		r.setMsg(msg);
 		r.setData(data);
 		return r;
 	}
 	public static BaseResp success(String msg, List<?> datas) { 
 		BaseResp r = new BaseResp(0);
 		r.setMsg(msg);
 		r.setDatas(datas);
 		return r;
 	}
 	/** * 功能描述：参数出错 */
 	public static BaseResp paramsError(String msg) { 
 		BaseResp r = new BaseResp(100);
 		r.setMsg(msg);
 		return r;
 	}
 
 	/** * 功能描述：验证出错 */
 	public static BaseResp validError(String msg) { 
 		BaseResp r = new BaseResp(101);
 		r.setMsg(msg);
 		return r;
 	}
 
 	/** * 功能描述：逻辑判断出错 */
 	public static BaseResp logicError(String msg) { 
 		BaseResp r = new BaseResp(102);
 		r.setMsg(msg);
 		return r;
 	}
 
 	/** * 功能描述：未登录 */
 	public static BaseResp invalidLogin(String url) { 
 		BaseResp r = new BaseResp(9888);
 		r.data = url;
 		return r;
 	}
 
 	/** * 功能描述：无权限 */
 	public static BaseResp invalidPerms(String msg) { 
 		BaseResp r = new BaseResp(9889);
 		r.setMsg(msg);
 		return r;
 	}
 
 }

**JsonMsgUtil.java（获取.properties文件属性的工具类）**

package com.jack.framework.json;
    
    import java.io.IOException;
    import java.io.UnsupportedEncodingException;
    import java.util.Properties;
    
    import org.springframework.core.io.support.PathMatchingResourcePatternResolver;
    import org.springframework.core.io.support.PropertiesLoaderUtils;
    
    import lombok.extern.slf4j.Slf4j;
    
    /** * 功能说明:资源工具类 */
    @Slf4j
    public final class JsonMsgUtil { 
    
    	private static Properties propertie = new Properties();
    
    	private static String DEFAULT_MESSAGE = "";
    
    	static { 
    		try { 
    			propertie = PropertiesLoaderUtils.loadProperties(new PathMatchingResourcePatternResolver().getResource("classpath:conf/json-msg.properties"));
    		} catch (IOException e1) { 
    			String s = "Load resource file failed.";
    			log.error(s);
    		}
    	}
    
    	public static String getMsg(String key) { 
    		String message = propertie.getProperty(key, DEFAULT_MESSAGE);
    		try { 
    			message = new String(message.getBytes("UTF-8"), "UTF-8");
    		} catch (UnsupportedEncodingException e) { 
    			e.printStackTrace();
    			return DEFAULT_MESSAGE;
    		}
    		return message;
    	}
    
    	public static String getMsg(int key) { 
    		String message = propertie.getProperty("" + key, DEFAULT_MESSAGE);
    		try { 
    			message = new String(message.getBytes("UTF-8"), "UTF-8");
    		} catch (UnsupportedEncodingException e) { 
    			e.printStackTrace();
    			return DEFAULT_MESSAGE;
    		}
    		return message;
    	}
    
    }

**json-msg.properties（定义系统的统一返回码）**  
通常中文需要转成Unicode格式

##################
    #JSON MSG
    #返回码规划如下
    #100 --默认参数异常
    #1XXX --通用错误异常
    #2XXX --业务模块异常
    #3XXX --API模块异常
    
    #8XXX --管理模块异常
    #9XXX --系统异常
    ##################
    
    ##########################正常############################
    0=成功
    
    ##########################业务模块异常############################
    #2X0X--业务通用模块
    2001=文件上传失败
    2002=业务参数异常
    2003=你无权操作
    
    ##########################API模块异常############################
    3999=时间戳错误
    3998=随机码错误
    3997=签名错误
    
    3000=未登录或已失效，请重新登录
    
    ##########################系统异常############################
    9400=无效请求
    9404=非法请求
    9405=方法不被允许
    9406=无法接受
    9415=不支持的媒体类型
    9500=执行异常
    
    9900=运行时异常
    9901=空值异常
    9902=数据类型转换异常
    9903=IO异常
    9904=未知方法异常
    9905=数组越界异常
    
    9888=未登录或已失效，请重新登录
    9889=权限不足
    
    9997=Json格式错误
    9998=数据格式错误
    9999=系统异常

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