利用SSM(springmvc+spring+mybatis)实现多表联合查询

最近在做在eclipse + maven搭建SSM框架下做一个简单的后台管理系统，因为是第一次搭建SSM项目，在mybatis进行多表连接查询的时候遇到问题，不知道如何进行处理？在网上搜了一下解决方法是，以实现，记录下自己的实现方案。

1. 表之间的关系如下图所示：

环境搭建的是eclipse + maven+SpringMVC + Spring + MyBatis，前端用到的是bootstrap框架。
因为是第一次做SSM项目没有用到 mybatis 的自动生成工具 mybatis generator 生成的实体类、mapper 接口、以及 mapper xml 文件。都是自己写的。

Project 类

import java.util.List;

import org.apache.ibatis.type.Alias;

/**
 * @author  作者:
 * @date 创建时间：2018年10月19日 
 * @version 1.0 
 * @author
 */
@Alias("Project")
public class Project {
	
	private String gid        ;
	private String activity  ;
	private String activity_end;
	private String src ;
	private String src2;
	private String src3;
	private String msgSuc;
	private String msgSuc1;
	private String jdr;
	private String createtime;
	private List<Lottery> lotterys;//这个是一个重点与Lottery实体类进行关联
	public String getGid() {
		return gid;
	}
	public void setGid(String gid) {
		this.gid = gid;
	}
	public String getActivity() {
		return activity;
	}
	public void setActivity(String activity) {
		this.activity = activity;
	}
	public String getSrc() {
		return src;
	}
	public void setSrc(String src) {
		this.src = src;
	}
	public String getActivity_end() {
		return activity_end;
	}
	public void setActivity_end(String activity_end) {
		this.activity_end = activity_end;
	}
	public String getSrc2() {
		return src2;
	}
	public void setSrc2(String src2) {
		this.src2 = src2;
	}
	public String getSrc3() {
		return src3;
	}
	public void setSrc3(String src3) {
		this.src3 = src3;
	}
	public String getMsgSuc() {
		return msgSuc;
	}
	public void setMsgSuc(String msgSuc) {
		this.msgSuc = msgSuc;
	}
	public String getMsgSuc1() {
		return msgSuc1;
	}
	public void setMsgSuc1(String msgSuc1) {
		this.msgSuc1 = msgSuc1;
	}
	public String getJdr() {
		return jdr;
	}
	public void setJdr(String jdr) {
		this.jdr = jdr;
	}
	public String getCreatetime() {
		return createtime;
	}
	public void setCreatetime(String createtime) {
		this.createtime = createtime;
	}
	
	public List<Lottery> getLottery() {
		return lotterys;
	}
	public void setLottery(List<Lottery> lotterys) {
		this.lotterys = lotterys;
	}
	@Override
	public String toString() {
		return "Project [gid=" + gid + ", activity=" + activity + ", activity_end=" + activity_end + ", src=" + src
				+ ", src2=" + src2 + ", src3=" + src3 + ", msgSuc=" + msgSuc + ", msgSuc1=" + msgSuc1 + ", jdr=" + jdr
				+ ", createtime=" + createtime + "]";
	}
	public Project(String gid, String activity, String activity_end, String src, String src2, String src3,
			String msgSuc, String msgSuc1, String jdr) {
		super();
		this.gid = gid;
		this.activity = activity;
		this.activity_end = activity_end;
		this.src = src;
		this.src2 = src2;
		this.src3 = src3;
		this.msgSuc = msgSuc;
		this.msgSuc1 = msgSuc1;
		this.jdr = jdr;
	}
	public Project() {
		super();
	}
	
}

Lottery类

import org.apache.ibatis.type.Alias;

/**
 * @author  作者:
 * @date 创建时间：2018年10月19日 
 * @version 1.0 
 * @author
 */
@Alias("Lottery")
public class Lottery {
	private String id;  
	private String project_id; 
	private String url; 
	private String settingId;
	private String title; 
	private String settingTitle;
	private String days_newCust; 
	private String days_oldCust;
	private String appid; //appid
	private String appSecret; 
	private String awardType; 
	private String status;
	private String mete;
	private String mutex;
	private String createtime;/
	private String jdr;
	
	public String getId() {
		return id;
	}

	public void setId(String id) {
		this.id = id;
	}

	public String getProject_id() {
		return project_id;
	}

	public void setProject_id(String project_id) {
		this.project_id = project_id;
	}

	public String getUrl() {
		return url;
	}

	public void setUrl(String url) {
		this.url = url;
	}

	public String getSettingId() {
		return settingId;
	}

	public void setSettingId(String settingId) {
		this.settingId = settingId;
	}

	public String getTitle() {
		return title;
	}

	public void setTitle(String title) {
		this.title = title;
	}

	public String getSettingTitle() {
		return settingTitle;
	}

	public void setSettingTitle(String settingTitle) {
		this.settingTitle = settingTitle;
	}

	public String getDays_newCust() {
		return days_newCust;
	}

	public void setDays_newCust(String days_newCust) {
		this.days_newCust = days_newCust;
	}

	public String getDays_oldCust() {
		return days_oldCust;
	}

	public void setDays_oldCust(String days_oldCust) {
		this.days_oldCust = days_oldCust;
	}

	public String getAppid() {
		return appid;
	}

	public void setAppid(String appid) {
		this.appid = appid;
	}

	public String getAppSecret() {
		return appSecret;
	}

	public void setAppSecret(String appSecret) {
		this.appSecret = appSecret;
	}

	public String getAwardType() {
		return awardType;
	}

	public void setAwardType(String awardType) {
		this.awardType = awardType;
	}

	public String getStatus() {
		return status;
	}

	public void setStatus(String status) {
		this.status = status;
	}

	public String getMete() {
		return mete;
	}

	public void setMete(String mete) {
		this.mete = mete;
	}

	public String getMutex() {
		return mutex;
	}

	public void setMutex(String mutex) {
		this.mutex = mutex;
	}

	public String getCreatetime() {
		return createtime;
	}

	public void setCreatetime(String createtime) {
		this.createtime = createtime;
	}

	public String getJdr() {
		return jdr;
	}

	public void setJdr(String jdr) {
		this.jdr = jdr;
	}

	public Lottery() {
		super();
	}

	public Lottery(String id, String project_id, String url, String settingId, String title, String settingTitle,
			String days_newCust, String days_oldCust, String appid, String appSecret, String awardType, String status,
			String mete, String mutex, String jdr) {
		super();
		this.id = id;
		this.project_id = project_id;
		this.url = url;
		this.settingId = settingId;
		this.title = title;
		this.settingTitle = settingTitle;
		this.days_newCust = days_newCust;
		this.days_oldCust = days_oldCust;
		this.appid = appid;
		this.appSecret = appSecret;
		this.awardType = awardType;
		this.status = status;
		this.mete = mete;
		this.mutex = mutex;
		this.jdr = jdr;
	}

	
}

project 与 lottery 是1:1的关系，在 project zhong 加入一个lottery属性，对应一对一的关系。

然后就是mapper接口与xml文件

mapper :ProjectDao

public interface ProjectDao {
	
    
    //查询项目信息列表
    List<Project> selectAllProject();

}

xml ProjectDao.xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE mapper
        PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.**.mapper.ProjectDao">
    <resultMap id="queryForListMap" type="com.**.pojo.Project">  
        <id column="gid" property="gid" jdbcType="VARCHAR"/>  
        <result column="activity" property="activity" jdbcType="VARCHAR"/>  
        <result column="activity_end" property="activity_end" jdbcType="VARCHAR"/>  
        <result column="msgSuc" property="msgSuc" jdbcType="VARCHAR"/>  
        <result column="msgSuc1" property="msgSuc1" jdbcType="VARCHAR"/>  
        <collection property="lotterys" javaType="java.util.List" ofType="com.**.pojo.Lottery">  
            <id column="r_id" property="id" jdbcType="VARCHAR" />  
            <result column="r_settingId" property="settingId" jdbcType="VARCHAR" />  
            <result column="r_title" property="title" jdbcType="VARCHAR" />  
            <result column="r_settingTitle" property="settingTitle" jdbcType="VARCHAR" />  
            <result column="r_days_newCust" property="days_newCust" jdbcType="VARCHAR" />  
            <result column="r_days_oldCust" property="days_oldCust" jdbcType="VARCHAR" />  
             <result column="r_awardType" property="awardType" jdbcType="VARCHAR" />  
              <result column="r_mete" property="mete" jdbcType="VARCHAR" />  
        </collection>  
    </resultMap>  
    <!--用户表列名片段-->
    <sql id="userColumn">
        gid, activity, activity_end, src,src2,src3,msgSuc,msgSuc1,jdr,createtime
    </sql>
     <select id="selectAllProject" resultMap="queryForListMap">
        select p.gid, p.activity, p.activity_end, p.src,p.src2,p.src3,p.msgSuc,p.msgSuc1,p.jdr,
        l.id r_id,l.settingId r_settingId, l.title r_title,l.settingTitle r_settingTitle,l.days_newCust r_days_newCust,l.days_oldCust r_days_oldCust,l.appid,l.appSecret,l.awardType r_awardType,l.status,l.mete r_mete,l.mutex 
        from system_project  p left join system_lottery l 
        on p.gid=l.project_id
    </select>
     <delete id="deleteByPrimaryKey" parameterType="java.lang.String" >
      delete from system_project
      where gid = #{gid}
    </delete>
</mapper>

service 层代码

public interface ProjectService {
	
	List<Project> selectAllProject();
}

service impl

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@Service("projectService")
public class ProjectServiceImpl implements ProjectService {
     
	@Autowired
    public ProjectDao projectDao;

	@Override
	public List<Project> selectAllProject() {
		// TODO Auto-generated method stub
		return this.projectDao.selectAllProject();
	}

}

controler层往前端传的是json

	    @RequestMapping("/showProjectList")
	    @ResponseBody
	    public String GetDepartment()
        {
            List<Project> list = projectService.selectAllProject();
            Gson gson = new Gson();
            System.err.println("**********list*********"+gson.toJson(list));
	        System.err.println("**********list*********"+gson.toJson(list));
	        System.err.println("**********list*********"+gson.toJson(list));
			return  gson.toJson(list);
              
        }

传的json是复杂的嵌套类型如下图：

前端用到的了bootstrap框架

<script type="text/javascript">

$(function () {

    //1.初始化Table
    var oTable = new TableInit();
    oTable.Init();

    //2.初始化Button的点击事件
    operate.operateInit();

});
	//table
	var TableInit = function () {
    var oTableInit = new Object();
    //初始化Table
    oTableInit.Init = function () {
        $('#tb_departments').bootstrapTable({
            url: '${pageContext.request.contextPath}/showProjectList',         //请求后台的URL（*）
            method: 'get',                      //请求方式（*）
            toolbar: '#toolbar',                //工具按钮用哪个容器
            striped: true,                      //是否显示行间隔色
            cache: false,                       //是否使用缓存，默认为true，所以一般情况下需要设置一下这个属性（*）
            pagination: true,                   //是否显示分页（*）
            paginationLoop: false,
            sortable: true,                     //是否启用排序
            sortOrder: "asc",                   //排序方式
            queryParams: oTableInit.queryParams,//传递参数（*）
            sidePagination: "client",           //分页方式：client客户端分页，server服务端分页（*）
            pageNumber:1,                       //初始化加载第一页，默认第一页
            pageSize: 15,                       //每页的记录行数（*）
            pageList: [15],       				//可供选择的每页的行数（*）
            search: true,                       //是否显示表格搜索，此搜索是客户端搜索，不会进服务端，所以，个人感觉意义不大
            strictSearch: false,
            showColumns: false,                  //是否显示所有的列
            showRefresh: true,                  //是否显示刷新按钮
            minimumCountColumns: 1,             //最少允许的列数
            clickToSelect: false,                //是否启用点击选中行
            uniqueId: "gid",                     //每一行的唯一标识，一般为主键列
            showToggle:false,                    //是否显示详细视图和列表视图的切换按钮
            cardView: false,                    //是否显示详细视图
            detailView: false,                  //是否显示父子表
            undefinedText:'-',					//当数据为 undefined 时显示的字符
            columns: [{
                checkbox: false,
                title: '序号',
		        field: '',
		        align: 'center',
		        formatter: function (value, row, index) {
		            return index + 1;
		        }
            }, {
                field: 'lotterys',
                title: '名称',
                formatter: uidHandle,//自定义方法设置uid跳转链接
                sortable:false
               
            }, {
                field: 'activity',
                title: '活动ID'
            }, {
                field: 'activity_end',
                title: '结束日期'
            }, {
                field: 'lotterys',
                title: '标识',
                formatter : function(value,row, index){ //主要配置在这里 
                	return  value[0].settingId; }
                
            }, {
                field: 'lotterys',
                title: '名称',
                sortable:false,
                formatter : function(value,row, index){ //主要配置在这里 
                	return  value[0].title; }
            }, {
                field: 'lotterys',
                title: '天数',
                formatter : function(value,row, index){ //主要配置在这里 
                	return  value[0].days_newCust; }
            }, {
                field: 'lotterys',
                title: '类型',
                formatter : function(value,row, index){ //主要配置在这里 
                	return  value[0].awardType; }
            }, {
                field: 'lotterys',
                title: '金额/收益率',
                formatter : function(value,row, index){ //主要配置在这里 
                	return  value[0].mete; }
            }, {
                field: 'dataBtn',
                title: '操作',
                formatter: dataFun
            }]
        });
    };

    //条件查询
    oTableInit.queryParams = function (params) {
        var temp = {   //这里的键的名字和控制器的变量名必须一直，这边改动，控制器也需要改成一样的
            limit: params.limit,   //页面大小
            offset: params.offset,  //页码
            search: params.search,
            settingTitle: $("#txt_search_name").val(),//后台请求传的查询参数
            activity:$("#txt_search_id").val(),
            activity_end:$("txt_search_time").val(),
        };
	        return temp;
	    };
	    return oTableInit;
	};
	
	function serachUser() {
	    $("#tb_departments").bootstrapTable('refresh');
	}

	//button
	var operate = {
	    // 初始化按钮事件
	    operateInit : function() {
			
	    },

	}

	//自定义图事件
	  //自定义跳转
	  var uidHandle = function (value,row,index) {
		  var html = "<a href='${pageContext.request.contextPath}/goLook?gid=" + row.gid + "'>" + value[0].settingTitle + "</a>";
	      return html;
	  }
	  //自定义按钮
	  var dataFun = function (value,row,index) {
		  var html = "<a class='btn btn-default' href=' ${pageContext.request.contextPath}/updateByPrimaryGid?gid=" + row.gid + "'><span class='glyphicon glyphicon-edit' aria-hidden='true'></span></ a><a class='btn btn-default'  onclick='confirmdelete()' href='${pageContext.request.contextPath}/deleteByPrimaryKey?gid=" + row.gid + "'><span class='glyphicon glyphicon-remove' aria-hidden='true'></span></ a>";
	      return html;
	  }
	  
	 function confirmdelete(){
	    if (!confirm("确认要删除？")) {  window.event.returnValue = false;  }  
	}
	  
</script>

对于嵌套的json boostrap有处理方法需要如下操作：

{
                field: 'lotterys',
                title: '类型',
                formatter : function(value,row, index){ //主要配置在这里 
                	return  value[0].awardType; }
  }

最后的实现效果如下：

bootstrap 参考地址：https://www.cnblogs.com/landeanfen/p/4976838.html
本文实现方法参考文章：https://blog.csdn.net/u012661010/article/details/76408566