使用Mybatis实现简单和复杂查询----通用工具类

最近学着使用Mybatis和SpringBoot进行整合，涉及到多种数据类型时，要分别写入每个映射类，觉得过于繁琐。寻思着想了个简单的方式，利用map完成，具体如何实现呢。

下面给大家分享个简单的例子，我自认为复杂的可以借鉴。

<select id="getDeptMap" parameterType="pd" resultType="pd">
		select d.deptno,d.dname from dept d
		<where>
			1 = 1 
			<if test="deptno != null and deptno != '' ">
				and d.deptno = #{deptno}
			</if>
		</where>
	</select>

mybatis的配置项

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE configuration   
    PUBLIC "-//mybatis.org//DTD Config 3.0//EN"   
    "http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>
	<!-- 进行Mybatis的相应的环境的属性定义 -->
	<settings>	<!-- 在本项目之中开启二级缓存 -->
		<setting name="cacheEnabled" value="true"/>
	</settings>
	
	<!-- 实体映射 -->
	<typeAliases>
		<typeAlias type="cn.linkpower.util.PageData" alias="pd"/>
	</typeAliases>
</configuration>

springboot数据库连接池以及配置项导入的配置  application.yml

server:
  port: 80
mybatis:
  config-location: classpath:mybatis/mybatis.cfg.xml    # mybatis配置文件所在路径
  type-aliases-package: cn.linkpower.vo                 # 定义所有操作类的别名所在包
  mapper-locations:                                     # 所有的mapper映射文件
  - classpath:mybatis/mapper/**/*.xml
spring:
  datasource:
   type: com.alibaba.druid.pool.DruidDataSource         # 配置当前要使用的数据源的操作类型
   driver-class-name: org.gjt.mm.mysql.Driver           # 配置MySQL的驱动程序类
   url: jdbc:mysql://127.0.0.1:3306/javademo            # 数据库连接地址
   username: root                                       # 数据库用户名
   password: root                                       # 数据库连接密码
   filters: stat,wall,log4j                               # 开启druid监控还需要进行一项过滤配置
   dbcp2:                                               # 进行数据库连接池的配置
     min-idle: 5                                        # 数据库连接池的最小维持连接数    
     initial-size: 5                                    # 初始化提供的连接数
     max-total: 10                                      # 最大的连接数
     max-wait-millis: 200                               # 等待连接获取的最大超时时间

下面的这个工具类才是重点

package cn.linkpower.util;

import java.io.BufferedReader;
import java.io.Reader;
import java.util.Collection;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import java.util.Set;

import javax.servlet.http.HttpServletRequest;

import com.alibaba.druid.proxy.jdbc.ClobProxyImpl;
/**
 * 参数封装Map
 * @author 香蕉不拿拿先生
 *
 */
@SuppressWarnings("rawtypes")
public class PageData extends HashMap implements Map{
	
	private static final long serialVersionUID = 1L;
	
	Map map = null;
	HttpServletRequest request;
	
	@SuppressWarnings("unchecked")
	public PageData(HttpServletRequest request){
		this.request = request;
		Map properties = request.getParameterMap();
		
		Map returnMap = new HashMap(); 
		//将map的key和value组成的数据包装成一个Map.Entry对象
		Iterator entries = properties.entrySet().iterator(); 
		Map.Entry entry; 
		String name = "";  
		String value = "";  
		while (entries.hasNext()) {
			//获取单个对象
			entry = (Map.Entry) entries.next(); 
			name = (String) entry.getKey(); 
			Object valueObj = entry.getValue(); 
			if(null == valueObj){ 
				value = ""; 
			}else if(valueObj instanceof String[]){
				//值的类型是String类型的数组
				String[] values = (String[])valueObj;
				for(int i=0;i<values.length;i++){ 
					 value = values[i] + ",";
				}
				//value.length()-1  去掉最后一个 ","
				value = value.substring(0, value.length()-1); 
			}else{
				value = valueObj.toString(); 
			}
			//将每个解析出来的数据保存在map集合中
			returnMap.put(name, value); 
		}
		map = returnMap;
	}
	
	public PageData() {
		map = new HashMap();
	}
	
	@Override
	public Object get(Object key) {
		Object obj = null;
		if(map.get(key) instanceof Object[]) {
			Object[] arr = (Object[])map.get(key);
			obj = request == null ? arr:(request.getParameter((String)key) == null ? arr:arr[0]);
		} else {
			obj = map.get(key);
		}
		return obj;
	}
	
	public String getString(Object key) {
		return (String)get(key);
	}
	
	@SuppressWarnings("unchecked")
	@Override
	public Object put(Object key, Object value) {
		if(value instanceof ClobProxyImpl){ 			//读取oracle Clob类型数据
			try {
				ClobProxyImpl cpi = (ClobProxyImpl)value;
				Reader is = cpi.getCharacterStream(); 	//获取流
				BufferedReader br = new BufferedReader(is);
				String str = br.readLine();
				StringBuffer sb = new StringBuffer();
				while(str != null){						//循环读取数据拼接到字符串
					sb.append(str);
					sb.append("\n");
					str = br.readLine();
				}
				value = sb.toString();
			} catch (Exception e) {
				e.printStackTrace();
			}
		}
		return map.put(key, value);
	}
	
	@Override
	public Object remove(Object key) {
		return map.remove(key);
	}

	public void clear() {
		map.clear();
	}

	public boolean containsKey(Object key) {
		return map.containsKey(key);
	}

	public boolean containsValue(Object value) {
		return map.containsValue(value);
	}

	public Set entrySet() {
		return map.entrySet();
	}

	public boolean isEmpty() {
		return map.isEmpty();
	}

	public Set keySet() {
		return map.keySet();
	}

	@SuppressWarnings("unchecked")
	public void putAll(Map t) {
		map.putAll(t);
	}

	public int size() {
		return map.size();
	}

	public Collection values() {
		return map.values();
	}
	
}

三层架构的代码

dao层

package cn.linkpower.dao;

import java.util.List;

import org.apache.ibatis.annotations.Mapper;

import cn.linkpower.util.PageData;
import cn.linkpower.vo.Dept;

@Mapper   //必须添加此项注解  不然接口和xml文件无法整合
public interface IDeptDAO {
	//测试map传入传出
	public List<Dept> getDeptMap(PageData pd)throws Exception;
}

service层

package cn.linkpower.service;

import java.util.List;
import java.util.Map;

import org.springframework.transaction.annotation.Propagation;
import org.springframework.transaction.annotation.Transactional;

import cn.linkpower.util.PageData;
import cn.linkpower.vo.Dept;

public interface IDeptService {
	//采用传入map类型进行数据的添加操作
	@Transactional(readOnly = true)
	public List<Dept> getDeptMap(PageData pd) throws Exception;
}

实现层

package cn.linkpower.service.impl;

import java.util.List;

import javax.annotation.Resource;
import org.springframework.stereotype.Service;
import cn.linkpower.dao.IDeptDAO;
import cn.linkpower.service.IDeptService;
import cn.linkpower.util.PageData;
import cn.linkpower.vo.Dept;

@Service
public class DeptService implements IDeptService {
	@Resource
	private IDeptDAO deptDao;
	
	//测试map方式传入和传出
	@Override
	public List<Dept> getDeptMap(PageData pd) throws Exception {
		return this.deptDao.getDeptMap(pd);
	}

}

基础控制层

package cn.linkpower.util;

import javax.servlet.http.HttpServletRequest;

import org.springframework.web.context.request.RequestContextHolder;
import org.springframework.web.context.request.ServletRequestAttributes;
import org.springframework.web.servlet.ModelAndView;

public class BaseController {
	protected Logger logger = Logger.getLogger(this.getClass());

	private static final long serialVersionUID = 6357869213649815390L;

	/**
	 * new PageData对象
	 * 
	 * @return
	 */
	public PageData getPageData() {
		return new PageData(this.getRequest());
	}

	/**
	 * 得到ModelAndView
	 * 
	 * @return
	 */
	public ModelAndView getModelAndView() {
		return new ModelAndView();
	}

	/**
	 * 得到request对象
	 * 
	 * @return
	 */
	public HttpServletRequest getRequest() {
		HttpServletRequest request = ((ServletRequestAttributes) RequestContextHolder.getRequestAttributes())
				.getRequest();
		return request;
	}

	/**
	 * 得到32位的uuid
	 * 
	 * @return
	 */
	public String get32UUID() {
		return UuidUtil.get32UUID();
	}


	public static void logBefore(Logger logger, String interfaceName) {
		logger.info("");
		logger.info("start");
		logger.info(interfaceName);
	}

	public static void logAfter(Logger logger) {
		logger.info("end");
		logger.info("");
	}
}

实现代码的控制层

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package cn.linkpower.controller;

import java.util.HashMap;
import java.util.List;
import java.util.Map;

import javax.annotation.Resource;
import javax.servlet.http.HttpServletRequest;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.ResponseBody;

import cn.linkpower.service.IDeptService;
import cn.linkpower.util.BaseController;
import cn.linkpower.util.JsonUtils;
import cn.linkpower.util.PageData;
import cn.linkpower.vo.Dept;

/**
 * 测试改进的控制器效果(验证mybatis传入map类型)
 * 
 * @author 香蕉不拿拿先生
 *
 */
@Controller
public class TestController extends BaseController {
	Logger log = LoggerFactory.getLogger(this.getClass());

	@Resource
	private IDeptService deptService;

	@RequestMapping(value = "/getDeptMap", method = RequestMethod.GET)
	@ResponseBody
	public Object getDeptMap() throws Exception {
		log.info("进入控制器");
		// 创建map集合对象 保存参数信息
		PageData pd = new PageData();

		// 调用父类的定义方法 通过请求创建指定的PageData对象
		pd = this.getPageData();
		// 和request.getParameter一样 deptnum
		String deptno = pd.getString("deptnum");
		log.info("获取到的数据：" + deptno);
		// 保存数据
		pd.put("deptno", deptno);
		List<Dept> deptList = this.deptService.getDeptMap(pd);

		JsonUtils jsonUtils = new JsonUtils();
		jsonUtils.setCode("200");
		jsonUtils.setMsg("ok");
		jsonUtils.setData(deptList);
		return jsonUtils;
		// http://localhost/getDeptMap?deptnum=1
	}

}

json工具类

package cn.linkpower.util;

public class JsonUtils {
	private String code;
	private String msg;
	private Object data;
	
	public String getCode() {
		return code;
	}
	public void setCode(String code) {
		this.code = code;
	}
	public String getMsg() {
		return msg;
	}
	public void setMsg(String msg) {
		this.msg = msg;
	}
	public Object getData() {
		return data;
	}
	public void setData(Object data) {
		this.data = data;
	}
	
	@Override
	public String toString() {
		return "JsonUtils [code=" + code + ", msg=" + msg + ", data=" + data + "]";
	}
}

运行springboot，访问http://localhost/getDeptMap?deptnum=3

数据库的结构

drop database if exists javademo;
create database mldn character set utf8;
use javademo;
create table dept(
	deptno   bigint   Auto_increment,
	dname    varchar(50),
	constraint pk_deptno primary key(deptno)
);
insert into dept(dname) values("开发部");
insert into dept(dname) values("财务部");
insert into dept(dname) values("市场部");
insert into dept(dname) values("后勤部");
insert into dept(dname) values("公关部");

我的代码的主要思想是使用map进行数据的保存操作，在mapper.xml文件中写的sql语句，是根据PageData类中保存的键值对进行参数的获取判断，然后进行查询数据库操作，如果数据参数很多，是不是也可以使用这个方式进行参数的保存pagadata和传递解析呢？

复杂的我暂未实现，如果大家有心得和更好的方式，还望大家能够分享下，小白不胜感激。

说到这里我在这追加说明一个上述的好的地方，application.yml中，我没有使用c3p0连接池，而是用的alibaba的？大家可以看下我写的配置项

package cn.linkpower.config;

import javax.sql.DataSource;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.boot.web.servlet.FilterRegistrationBean;
import org.springframework.boot.web.servlet.ServletRegistrationBean;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import com.alibaba.druid.pool.DruidDataSource;
import com.alibaba.druid.support.http.StatViewServlet;
import com.alibaba.druid.support.http.WebStatFilter;
/**
 * 拓展技能：进行druid数据库连接池的性能的监控操作  需要做一些配置(例如：你访问的ip地址是否是白名单、数据库sql监控等)
 * 访问方式：   http://localhost/druid/
 * @author 76519
 *
 */
@Configuration
public class DruidConfig {
	@Bean
	public ServletRegistrationBean druidServlet() { // 主要实现WEB监控的配置处理
		System.out.println("WEB监控的配置处理");
		//想用使用 Servlet 功能，就必须要借用 Spring Boot 提供的 ServletRegistrationBean 接口
		//访问方式http://localhost/druid/getAll   启动alibaba的druid数据库连接池自带的servlet
		ServletRegistrationBean servletRegistrationBean = new ServletRegistrationBean(
				new StatViewServlet(), "/druid/*"); // 现在要进行druid监控的配置处理操作
		servletRegistrationBean.addInitParameter("allow",
				"127.0.0.1,192.168.28.159"); // 白名单
		servletRegistrationBean.addInitParameter("deny", "192.168.28.200"); // 黑名单
		servletRegistrationBean.addInitParameter("loginUsername", "admin"); // 用户名
		servletRegistrationBean.addInitParameter("loginPassword", "hello"); // 密码
		servletRegistrationBean.addInitParameter("resetEnable", "false"); // 是否可以重置数据源
		return servletRegistrationBean ;
	}
	@Bean
	public FilterRegistrationBean filterRegistrationBean() {
		FilterRegistrationBean filterRegistrationBean = new FilterRegistrationBean() ;
		filterRegistrationBean.setFilter(new WebStatFilter());
		filterRegistrationBean.addUrlPatterns("/*"); // 所有请求进行监控处理
		filterRegistrationBean.addInitParameter("exclusions", "*.js,*.gif,*.jpg,*.css,/druid/*");
		return filterRegistrationBean ;
	}
	@Bean
	@ConfigurationProperties(prefix = "spring.datasource")
	public DataSource druidDataSource() {
		return new DruidDataSource();
	}
}

然后启动Springboot项目，浏览器访问http://localhost/druid/login.html输入你配置中的写的用户名和密码。这个作为一个惊喜的发现分享下吧。