{"id":154317,"date":"2020-09-06T20:44:55","date_gmt":"2020-09-06T12:44:55","guid":{"rendered":"http:\/\/4563.org\/?p=154317"},"modified":"2020-09-06T20:44:55","modified_gmt":"2020-09-06T12:44:55","slug":"%e6%b1%82%e5%8a%a9-mybatis-%e9%87%8c%e8%be%b9%e5%8f%af%e4%bb%a5%e4%bd%bf%e7%94%a8-collection-%e6%a0%87%e7%ad%be%e9%87%8c%e8%be%b9%e5%b5%8c%e5%a5%97-association-%e6%a0%87%e7%ad%be%e5%98%9b-%e5%a6%82","status":"publish","type":"post","link":"http:\/\/4563.org\/?p=154317","title":{"rendered":"[\u6c42\u52a9] Mybatis \u91cc\u8fb9\u53ef\u4ee5\u4f7f\u7528 collection \u6807\u7b7e\u91cc\u8fb9\u5d4c\u5957 association \u6807\u7b7e\u561b \u5982\u679c\u53ef\u4ee5\u7684\u8bdd\u6211\u8fd9\u4e2a\u5199\u7684\u54ea\u91cc\u6709\u95ee\u9898\uff1f \u8be6\u7ec6\u5728\u6587\u4e2d"},"content":{"rendered":"
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[\u6c42\u52a9] Mybatis \u91cc\u8fb9\u53ef\u4ee5\u4f7f\u7528 collection \u6807\u7b7e\u91cc\u8fb9\u5d4c\u5957 association \u6807\u7b7e\u561b \u5982\u679c\u53ef\u4ee5\u7684\u8bdd\u6211\u8fd9\u4e2a\u5199\u7684\u54ea\u91cc\u6709\u95ee\u9898\uff1f \u8be6\u7ec6\u5728\u6587\u4e2d <\/h1>\n

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\u8cc7\u6df1\u5927\u4f6c : gzk329 <\/span> <\/i> 5<\/span> <\/div>\n
<\/div>\n<\/p><\/div>\n<\/p><\/div>\n<\/p><\/div>\n
<\/p>\n
public class Employee {     private String eid;     private String name;     private Date startTime;     private Manager manager;  public class Manager {     private String mid;     private String name;     private Employee employee;  <\/code><\/pre>\n
\"[\u6c42\u52a9]<\/p>\n
\u6211\u73b0\u5728\u5199\u4e86\u4e00\u4e2a\u65b9\u6cd5\u8981\u901a\u8fc7\u7ecf\u7406\u7684 ID \u67e5\u51fa\u7ecf\u7406 \u540c\u65f6\u4e00\u4e2a\u7ecf\u7406\u5bf9\u8c61\u91cc\u8fb9\u4f1a\u6709\u5bf9\u5e94\u7684\u591a\u4e2a\u96c7\u5458\uff0c\u7136\u540e\u96c7\u5458\u5bf9\u8c61\u91cc\u8fb9\u8fd8\u6709\u5bf9\u5e94\u7684\u7ecf\u7406\u4fe1\u606f \u53ef\u4ee5\u4f7f\u7528 collection \u6807\u7b7e\u91cc\u8fb9\u5d4c\u5957 association \u6807\u7b7e\u561b \u5982\u679c\u53ef\u4ee5\u7684\u8bdd\u6211\u8fd9\u4e2a\u5199\u7684\u54ea\u91cc\u6709\u95ee\u9898\uff1f<\/p>\n
    <select id=\"getEmployeeByManagerId\" resultMap=\"managerMap\">         select * from         employee e, manager m         where m.id = e.mid         and m.id = #{id};     <\/select>     <resultMap id=\"managerMap\" type=\"com.gzk.pojo.Manager\">         <result property=\"mid\" column=\"id\"\/>         <result property=\"name\" column=\"name\"\/>         <collection property=\"employee\" ofType=\"com.gzk.pojo.Employee\">             <result property=\"eid\" column=\"id\"\/>             <result column=\"name\" property=\"name\"\/>             <result property=\"startTime\" column=\"startTime\"\/>             <association property=\"manager\" column=\"mid\" >                 <result column=\"id\" property=\"mid\"\/>                 <result property=\"name\" column=\"name\"\/>             <\/association>         <\/collection>     <\/resultMap> <\/mapper> <\/code><\/pre>\n<\/p><\/div>\n
 \u5927\u4f6c\u6709\u8a71\u8aaa<\/b> (7<\/span>)        <\/div>\n
 <\/div>\n<\/p><\/div>\n<\/p><\/div>\n
    \n
  • \n
    \n
    \n
     \u4e3b<\/span> \u8cc7\u6df1\u5927\u4f6c : gzk329 <\/span>  <\/div>\n
     <\/i>            <\/span> <\/div>\n<\/p><\/div>\n
                                                                 “`
    [Manager(mid=051b89f3b6bd45aea71252ed16f1e5d0, name=\u8d75\u516d, employee=Employee{eid=’051b89f3b6bd45aea71252ed16f1e5d0′, name=’\u8d75\u516d’, startTime=Wed Sep 02 15:08:56 CST 2020, manager=null}), 
    Manager(mid=3aa1491a4adb47f89b0f7dab804bd9d9, name=\u674e\u56db, employee=Employee{eid=’3aa1491a4adb47f89b0f7dab804bd9d9′, name=’\u674e\u56db’, startTime=Sun Aug 02 15:08:47 CST 2020, manager=null})]
    “`
    \u5982\u679c\u53bb\u6389 association \u6807\u7b7e\u7684\u8bdd\u662f\u53ef\u4ee5\u67e5\u51fa\u6765\u7684 \u5c31\u662f\u67e5\u51fa\u6765\u7684\u96c7\u5458\u5bf9\u8c61\u91cc\u8fb9\u7684\u7ecf\u7406\u4fe1\u606f\u6ca1\u6709\u4e86                                                            <\/div>\n<\/p><\/div>\n<\/li>\n
  • \n
    \n
    \n
     \u4e3b<\/span> \u8cc7\u6df1\u5927\u4f6c : gzk329 <\/span>  <\/div>\n
     <\/i>            <\/span> <\/div>\n<\/p><\/div>\n
                                                                 \u8fd8\u6709\u4e24\u5f20\u8868\u5982\u679c\u6709\u540c\u540d\u7684\u5217
    \u6bd4\u5982 a \u8868\u6709\u4e00\u5217 id
    b \u8868\u4e5f\u6709\u4e00\u5217\u4e5f\u53eb id 
    mybatis \u91cc\u8fb9\u8be5\u600e\u4e48\u533a\u5206
    \u9664\u4e86\u8d77\u522b\u540d\uff1f                                                            <\/div>\n<\/p><\/div>\n<\/li>\n
  • \n
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     \u8cc7\u6df1\u5927\u4f6c : luhe <\/span>  <\/div>\n
     <\/i>            <\/span> <\/div>\n<\/p><\/div>\n
                                                                 \u662f List<Employee>\u5427                                                            <\/div>\n<\/p><\/div>\n<\/li>\n
  • \n
    \n
    \n
     \u8cc7\u6df1\u5927\u4f6c : wysnylc <\/span>  <\/div>\n
     <\/i>            <\/span> <\/div>\n<\/p><\/div>\n
                                                                 \u771f\u4e0d\u6015 N+1 \u554a                                                            <\/div>\n<\/p><\/div>\n<\/li>\n
  • \n
    \n
    \n
     \u4e3b<\/span> \u8cc7\u6df1\u5927\u4f6c : gzk329 <\/span>  <\/div>\n
     <\/i>            <\/span> <\/div>\n<\/p><\/div>\n
                                                                 @luhe \u662f\u7684 \u8fd9\u4e2a\u6211\u5df2\u7ecf\u6539\u597d\u4e86 \u4f46\u662f\u4e0d\u77e5\u9053\u600e\u4e48\u8bfb\u51fa\u7ecf\u7406\u4fe1\u606f<\/p>\n
    “`
    [Manager(mid=8179d370bff14f5b996023fce00745de, name=\u674e\u7ecf\u7406, employee=[Employee{eid=’051b89f3b6bd45aea71252ed16f1e5d0′, name=’\u8d75\u516d’, startTime=null, manager=null}, Employee{eid=’3aa1491a4adb47f89b0f7dab804bd9d9′, name=’\u674e\u56db’, startTime=null, manager=null}])]
    “`<\/p>\n
    “`
     <select id=”getEmployeeByManagerId” resultMap=”managerMap”>
     select m.id mid, m.name mName,e.id eid,e.name eName from
     employee e, manager m
     where m.id = e.mid
     and m.id = #{id};
     <\/select>
     <resultMap id=”managerMap” type=”com.gzk.pojo.Manager” >
     <result property=”mid” column=”mid”\/>
     <result property=”name” column=”mName”\/>
     <collection property=”employee” ofType=”com.gzk.pojo.Employee” >
     <result property=”eid” column=”eid”\/>
     <result column=”eName” property=”name”\/>
     <result property=”startTime” column=”startTime”\/>
     <!–<association property=”manager” column=”mid” >
     <result column=”mid” property=”id”\/>
     <result property=”name” column=”mName”\/>
     <\/association>–>
     <\/collection>
     <\/resultMap><\/p>\n
    “`                                                            <\/p><\/div>\n<\/p><\/div>\n<\/li>\n
  • \n
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     \u8cc7\u6df1\u5927\u4f6c : mmdsun <\/span>  <\/div>\n
     <\/i>            <\/span> <\/div>\n<\/p><\/div>\n
                                                                 \u4e0d\u5982\u5355\u8868\u67e5\uff0c\u7136\u540e\u624b\u52a8\u5faa\u73af\u67e5\u3002<\/p>\n
    mybatis \u4e00\u5bf9\u591a\u5173\u8054\u57fa\u672c\u6ca1\u4eba\u7528 \u867d\u7136\u6709\u4e00\u4e8c\u7ea7\u7f13\u5b58\u4f46\u672c\u8d28\u8fd8\u662f n+1 \u81f4\u547d\u7684\u662f\u8fd8\u4f1a\u5bfc\u81f4\u67d0\u4e9b\u5206\u9875\u63d2\u4ef6\u8ba1\u7b97\u4e0d\u51c6\u3002<\/p>\n
    jpa \u8fd9\u79cd\u4e00\u5bf9\u591a\u5173\u8054\u7684 idea \u53ef\u4ee5\u81ea\u52a8\u751f\u6210\u3002                                                            <\/p><\/div>\n<\/p><\/div>\n<\/li>\n
  • \n
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     \u8cc7\u6df1\u5927\u4f6c : Jrue0011 <\/span>  <\/div>\n
     <\/i>            <\/span> <\/div>\n<\/p><\/div>\n
                                                                 \u8fd9\u5faa\u73af\u5f15\u7528\u3002\u3002\u3002\u6216\u8bb8\u662f\u4f60\u7684 association \u6807\u7b7e\u6ca1\u6709\u6307\u5b9a\u5c5e\u6027 javaType=”com.gzk.pojo.Manager”                                                            <\/div>\n<\/p><\/div>\n<\/li>\n
  • \n","protected":false},"excerpt":{"rendered":"
    [\u6c42\u52a9] Mybatis \u91cc\u8fb9\u53ef\u4ee5…<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[],"tags":[],"_links":{"self":[{"href":"http:\/\/4563.org\/index.php?rest_route=\/wp\/v2\/posts\/154317"}],"collection":[{"href":"http:\/\/4563.org\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/4563.org\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/4563.org\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/4563.org\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=154317"}],"version-history":[{"count":0,"href":"http:\/\/4563.org\/index.php?rest_route=\/wp\/v2\/posts\/154317\/revisions"}],"wp:attachment":[{"href":"http:\/\/4563.org\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=154317"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/4563.org\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=154317"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/4563.org\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=154317"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}