使用mybatis的resultMap进行复杂查询

时间：2023-03-09 02:42:36
使用mybatis的resultMap进行复杂查询
记录下mybatis的集合查询中碰到的问题

MyBatis ofType和javaType区别

mybatis 关联查询 resultMap 同名冲突

使用mybatis的resultMap进行复杂查询
mybatis <collection>标签 类型为string时无法获取重复数据错误
使用resultMap进行一对多关联查询的方式有两种：
方法 1、 使用左连接查询所有关联数据
1.     <resultMap id="peopleResultMap" type="People">  
2.         <id property="id" column="id" />  
3.         <result property="name" column="name" />   
4.         <collection property="qqs" ofType="string" javaType="list">  
5.             <result column="qq" />  
6.         </collection>  
7.     </resultMap>  
8.       
9.     <select id="selectPeopleById" resultMap="peopleResultMap">  
10.         select p.*,pq.qq from  
11.         people p left join  people_qq pq on p.id = pq.people_id   
12.         where p.id = #{id}  
13.     </select>
如上面，左连接关联查询出qq表的qq字段，然后将qq通过resultMap的集合类放到这个List<String> qqs这个属性字段中。
优点：查询数据只需要查询一次就可以了。
缺点：因为左连接查询，people表一对多qq表，会查询出重复的id数据行。这样就无法使用到数据库自带的分页函数。
select p.*,pq.qq from  
         people p left join  people_qq pq on p.id = pq.people_id   
         where p.id = #{id} 
上面这个sql查询出来的数据格式
如下：
使用mybatis的resultMap进行复杂查询aaarticlea/png;base64,iVBORw0KGgoAAAANSUhEUgAAAXAAAADFCAYAAABNaalNAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsMAAA7DAcdvqGQAACQ9SURBVHhe7Z27kizHYabnkdaQcTAvIm8N6sQ8w9Jej4KCs7ZegNYqIOMYayhiTZnLEA8XmHPBlSBBkOIywAvktCqruroys76sysy/CofE/n/EF2RXVl7R9U12DtBzd3Ecx3H+KnMT+KtXry4f/vpbYw4nvLccZyt+j/TFAjen44fT2YvfI32xwM3p+OF09uL3SF8scHM6fjidvfg90hcL3JyOH05nL36P9IUF/q9/f/kvd88uP/zX9EG88ZO/u9z9zd9f/heVGZPhh9PZi98jfbHAzen44XT24vdIX/qOUCxw04AfTmcvfo/0xQI3p+OH09mL3yN92ThC+bvLP94ewg8uf3t3d7mLscBNJeuH88XlIX8/vffjy9O1dL/c+b7FAu9LhcAnef/tT5YH8h//6/BAWeCmkvThnOT88OL6csiLh1jQe+XO9zEWeF/2BU7HJT5CMQ0kD+eLh7WM42t75c73MhZ4XyxwczoWuLMXC7wvHUcoP7v88G98hGLqSR/O/Ijk6fLj97aOUPJy5/sYC7wvdb/EDDvu4aGaeHb54X/3DtzUs3o4w4769n567/LjH2c77L1y53sXC7wvLHBjDmT34dw7IvERyvc+FnhfLHBzOha4sxcLvC8WuDkdC9zZiwXeFwvcnI4fTmcvfo/0xQI3p+OH09mL3yN9scDN6fjhdPbi90hf7sLCGWPMu8ZpT7IDd5wz8rvf/e76//bz9s3bFc73Py3vEWeJBe6cnr2Hk6Rdwvl+xgLviwXunJ6th5MkrfDqo6dDefvmzaE8Pb0+lFcffnQor1+/ruLoWOB9scCd01N6OL/55g+D1FjEvZCEFUjCCiRhBZKwAsl6jyNigffFAndODz2cQd4WuA5JWIEEXYMaC7wvFrhzevKHc5a3Ba5DElYgOdeixALvy47Ap6/2vH+k/4iZy54e76NvkhuI/7TKtc5U9jC8WlKqt7p+5dbs0+Plnq7f0j6H8T/dvrV5f0mKk/6ysjEd/W3OoX3NlpTGUm5zTDJ/KG+MBb5AElYgCSuQmBV+9dVXReLnxwLvS0HgT5fH++nhfXjIBbBVFp79krxCvUUG45/JioRTrpdllN3cziSiWzOjeOay3jkMbd4/Dndck7QJ/d3uFfrbnEPPmu2NpdxmOqdjEj+csbwtcB2SsAJJWIHETVjgfdk9QtkSK5WFa7EPislEUVsvvS/Ib5HR9Hq9K26dQ5qozZXcggzV/urmMKZjzXbnl7TJ81FjgS+QhBVIwgokYQWSdQmnPQcLfN75zcRiSpPWrawHu8NwjHBrJ5SD0drmkCW0OY9n1f807rzL1v5q5hDSs2Z780vKw6ebYX6Pw7W53a26tbHAF0jCCiRhBZKwAol6C6cth+/A44xntLHworPerZ3jqt4YlmV+Dkzj6Z7Ddby3PvPXo9yPEXhxDtKaFcZSajOfz3ifviO3wBdIwgokYQWSsAJJeg+nPqcKfLijeBwQ6pJwpkC9USbZLnMlmFBPF2rIJFUY+1VyI+NudX1PU3+VcwhpXrMhW2MJSdpcfcLYr18TC3yBJKxAElYgCSuQoGtw6vLOBN5aRn2Nks1MR/e1ziFcKx1jpAnjXB9dtPRXO4cp7eu5NZYpUb3ww8QCTyAJK5CEFUjCCiRhBZJzDU5dDj8Df4pehvLbji7IIRJV+pF/o96YgrjO2IGPbRbO4LOU2m3vrzAHac2mYH8bbYZjqtv9q7H1JRZ46MMCPw6SsAJJWIHkXINTl3N/iZkJZZTFXJZIcrveJJKCVOMjjYFc3iFNc8jaS9tNx1m/LkuwbGMO3Wt2DfVXbjNk+gEyl9N6tiYR+PDP0gI/DpKwAklYgeRci7OfXYE7jppY4PMPFAv8GEjCCiRhBRJzLc5+LHDn9CwCX47CLPBjIAkrkIQVSMy1OPuxwJ3Tk56BT/n2z38e+fjtx4fy+unVoXz6ySeH8urVm0N5Mzy3R0JrqvDVV7/uxtmPBe6cHhJ4iAWuQxJWoDVVIDHX4NTFAndOjwW+QBJWIAkr0JoqkJxrcOpigTunpyTwEHroFUjCCiRhBZKwAklYgdZUgeRcg1OX5K/ShwfNmO8aevB7IQkrkIQVSMIKJGEFWlMFkvMeTn28A3dOT5D0Xujh74EkrEASViAJK5CEFWhNFUjQWzhtscCd01Mj8BASQCskYQWSsAJJWIEkrEBrqkCSLuG0xwJ3Tk+twOOQDGogCSuQhBVIwgokYQVaUwUSNdHzHnEscOc7iI9QFkjCCiRhBVpTBZL1TBwLvC8WuHN6Sg+n/zVCHZKwAq2pAombsMD7YoE7p4ceTv+XmMdAElagNVUgWZdw2rMj8Omb6fib9bgs/aa7geTr7OJvuku/Ba9Ub3X9yq3Z8ZsK4fot7XNIvx0w+zrVpD/6qtWO/jbn0L5mS0pjKbc5Jpk/lDcmF/gsbwtchySsQGuqQKLewmlLQeDzV5W2/oX18OyX5BXqLTII98XCKdfLkny17CSiWzOjeOay3jkMbcZfzZq0Cf1l36Xd1d/mHHrWbG8s5TbTOR2TWOCxvC1wHZKwAq2pAkl6D6c+u0coW2KlsnAt9kExmShq66X3BfktMpper3fFrXNIE7W5kluQodpf3RzGdKzZ7vySNnk+amaB5/K2wHVIwgq0pgok6Bqcuhws8HnnNxOLKU1at7Ie7A7DMcKtnVAORmubQ5bQ5jyeVf/TuPMuW/urmUNIz5rtzS8pD59uhvmd9VfpLXALvBanLofvwOOMZ7Sx8KKz3q2d46reGJZlfg5M4+mew3W8tz7z16PcjxF4cQ7SmhXGUmozn894n74jDwIneQfooVcgCSuQhBVIwgokYQVaUwWScw1OXU4V+HBH8Tgg1CXhTIF6o0yyXeZKMKGeLtSQSaow9qvkRsbd6vqepv4q5xDSvGZDtsYSkrS5+oSxX78mFvgCSViBJKxAa6pAcq7F2c87E3hrGfU1SjYzHd3XOodwrXSMkSaMc3100dJf7RymtK/n1limRPXCDxMLPIEkrEASViAJK9CaKpCYa3H2c/gZuP8qfU9/hTlIazYF+9toMxxT3e5fja0vFvgCSViBJKxAa6pAYq7F2c+5v8TMhDLKYi5LJLldbxJJQarxkcZALu+Qpjlk7aXtpuOsX5clWLYxh+41u4b6K7cZMv0AmctpPVtjgS+QhBVIwgq0pgok5lqc/ewK3HHUBIH/4ZtvkC+//PJQPvn440P54vPPD+Xzz47lk0GSR/LZ0OaR/Oa3v+3CqYsF7pyeIPAQC5wlrEASViAJK5Cca3DqYoE7p8cCXyAJK5CEFUjCCiTnGpy6WODO6ZkFHmKBHwtJWIEkrEBy3sOpjwXunJ5Y4CEW+HGQhBVIwgok6C2ctljgzunJBR5igR8DSViBJKxAki7htMd/ld68MyxwHZKwAklYgURNhPeD055kB/7tt98aczjh4aTrMSTjHkjCCiRhBZKwAklYgSSsQLKeif/5W+B9scDN6dQI3Pz/jQXeFwvcnI4F/pcB7bhzaBetsLfznrHA+2KBm9OpEXh+FEL3mH1Iyi2QhBVI4DPxuC3wvljg5nRKAu/9JSa1dQalM3C6911BElYgCSuQuGPmeVjgfbHAzemQwI/61wjzdrd5eXn/2fQlXc/ff//y7O7Z5f2X4foHl+d3zy8fDPe0/BKT+ziCl/gLS4IkrEASViBp54Q5W+B92RF4eGPfXZ69/7K67OX7z27fZDfy/IOofKozlU0PzF691fUrzz+41n0ZHkS4fqN9Dt9+8Dzqa37IryT9ZWUjHf1tzqF9zfK667GU2xxJ5g/ljeQCn+V9hMBzcgGrkLgVSMIKJGEFkrACCZuwwPtSEPi8U3l+ef48F8BW2beXD+DaRKi3yCDcFwunXC9jlN3cziSim/BG8cxlvXMY2nz2/uXl/DppE/q73Sv0tzmHnjXbG0u5zXROxxALPJa3Ba5DElYgCSuQrEs47dk9QtkSK5WFa+tdMJCJorZeel+Q3yKj6fV6V9w6h5SozZXcggzV/urmMNKxZrvzS9rk+ajMAs/lbYHrkIQVSMIKJOoSTnsOFvi885uJxZSS1q2sB7vDcIxwayeUr44RWueQEdqcx7Pqfxp3LtHW/mrmEOhZs735JeXh080wv/eHa3O7W3VrscAXSMIKJGEFkrACiXoLpy2H78BjxjPaWHjRWe/WznFVb4RlmZ8D03i653Ad763P/PUo92MEXpyDtGaFsZTazOcz3qfvyIPASd4BkrACSViBJKxAElYgCSuQhBVI0ls4bTlV4FvHAaEuCWcC6o0yyXaZK8GEerpQA5NUYexXyY2Mu9X1PU39Vc4h0LxmA1tjCSRtrj5h7NevwQJfIAkrkIQVSMIKJOktnLa8M4G3llFfo2Sz4wa6r3UO4VrpGCMljHN9dNHSX+0cJtrXc2ssE1G98MPEAk8gCSuQhBVIwgokYQWS9BZOWw4/A3+ZSfe2owtyiESVfuTfqDdSENcZO/CxzcIZfEap3fb+CnOQ1my5vupvo81wTHW7fzW2PoLA//THPyAkYYXPPv30UD7/7LND+fTTY/nk7dtD+eKLLw7l669/04TTlnN/iZkJZZTFXJZIcrveplTjI42B0tFD9Ryy9tJ203HWr8tO2cYcutfsCvVXbjMw/QCZy2k9W7HAF0jCCiRhBZKwAkm6hNOeXYEbo2KBL5CEFUjCCiRhBRJ1Cac9Frg5HQt8gSSsQBJWIAkrkKhLOO2xwM3pWOALJGEFkrACSViBRE2E94jTHgvcnI4FvkASViAJK5CEFUjWOfN7xGmPBW5OxwJfIAkrkIQVSMIKJOyc+T3itMcCN6djgS+QhBVIwgokYQUSds78HnHa479Kb74TSN4BkrACSViBJKxAElYgCSuQhBVI2PT+CDjtSXbgjnNGwsNJ8g6QhBVIwgokYQWSsAJJWIEkrDBLey8WeF8scOf0WOALJGEFkrACSbiVnljgfbHAndNjgS+QhBVIwgok5BrUWOB9scCd02OBL5CEFUjCCiTnFnpjgffFAndOz3cp8L2QpLcgCSuQhBVIwgokZQWfgZ8bC9w5PX8JAic510ASViAJK5CEFUjCCrPAiTgWeF92BP7i8nB3d7l/fLq+jsNlT4/30TfdDTy8uJaETHWmsofh1ZJSvdX1K7dmnx4v93T9lvY5XF48RH3dX5LipL+sbExHf5tzaF+zJaWxlNsck8wfyhvzrgVOYq6FJKxAElYgCSuQhBVI3L046xQE/nR5vJ8e3oeHXABbZeHZL8kr1FtkEO6LhVOul2WU3dzOJKJbM6N45rLeOQxt3j8Od1yTtAn93e4V+tucQ8+a7Y2l3GY6p2PyrgROQm6FJKxAElYgCSuQhBVIxApOmt0jlC2xUlm4FvugmEwUtfXS+4L8FhlNr9e74tY5pInaXMktyFDtr24OYzrWbHd+SZs8HzXvQuAk4x5IwgokYQWSsAJJWIEkrOCkOVjg885vJhZTmrRuZT3YHYZjhFs7oRyM1jaHLKHNeTyr/qdx51229lczh5CeNdubX1IePt0M83scrs3tbtWtzXcpcJKwAklYgSSsQBJWIAkrkIQVnDSH78DjjGe0sfCis96tneOq3hiWZX4OTOPpnsN1vLc+89ej3I8ReHEO0poVxlJqM5/PeJ++I7fAF0jCCiRhBZKwAklYwUlzqsCHO4rHAaEuCWcK1Btlku0yV4IJ9XShhkxShbFfJTcy7lbX9zT1VzmHkOY1G7I1lpCkzdUnjP36NQkC/5//52vkV7/61aF8+YtfHMovf/nLQ/nFF784ls+/OJTPD+a3//7vh+KkeWcCby2jvkbJZqaj+1rnEK6VjjHShHGujy5a+qudw5T29dway5SoXvhhYoEnkIQVUMIKgySPhCSsQBJWcNIcfgb+FL0M5bcdXZBDJKr0I/9GvTEFcZ2xAx/bLJzBZym1295fYQ7Smk3B/jbaDMdUt/tXY+uLBb6AElYYJHkkJGEFkrCCk+bcX2JmQhllMZclktyuN4mkINX4SGMgl3dI0xyy9tJ203HWr8sSLNuYQ/eaXUP9ldsMmX6AzOW0nq2xwBdQwgqDJI+EJKxAElZw0uwK3HHUWOALKGGFQZJHQhJWIAkrOGkscOf0WOALKGGFQZJHQhJWIAkrOGkscOf0WOALKGGFQZJHQhJWIAkrOGkscOf0WOALKGGFQZJHQhJWIAkrOGkscOf0WOALKGGFQZJHQhJWIAkrOGkscOf0WOALKGGFQZJHQhJWIAkrOGn8V+nNdwLJO0ASViAJK5CEFVDCCoMkj4QkrEASVnDS3H34628vgSDwu//2c2MOxwJfQAkrDJI8EpKwAklYwUljgZvTscAXUMIKgySPhCSsQBJWcNJY4OZ0LPAFlLDCIMkjIQkrkIQVnDQWuDkdC3wBJawwSPJISMIKJOFenHUscHM6FvgCSlhhkOSRkIQVSMQlnPZY4OZ0LPAFlLDCIMkjIQkrkKi3cNqyI/Avxm+qe/qXN9Vl9//y57HhW/7ti6h8qjPl95eHinqr69e8+Mm17uPXybfw3a7faJ/D3U9+P7Y15c+Xx8eoLOkvKxvp6G9zDu1rltddj6Xc5kgyfyhvxAJfQAkrDJI8EpKwAkl6D6c+BYG/uTx+FYp/f3nxb7kAtsp+fnmAaxOh3iKDcF8snHK9jFF2czuTiG7CG8Uzl/XOYWjzq68v9/PrpE3o73av0F/e5q2/3jXbG0u5zXROx0DiniEJK5CEFUjCCihhhUGSR0ISViBB7+HUZ/cIZUusVBaurXfBQCaK2nrpfUF+i4ym1+tdcescUqI2V3ILMlT7q5vDSMea7c4vaZPno0LiniEJK5CEFUjCCihhhUGSR0ISViBB7+HU52CBzzu/ObGYUtK6lfVgdxiOEW7thPLVMULrHDJCm/N4Vv1P484l2tpfzRwCPWu2N7+kPHy6Geb3OFybs1W3hv/xv3+5yes3Hx/Kq1dvDuX1m7eH8ur1MMYjeXp9KG/efnIov/nt77pw6nL4DjxmPKONhRed9W7tHFf1RliW+Tkwjad7Dtfx3vrMX49yP0bgcZJyac0KYym1mc9nvE/bkZO0Y0jCCiRhBZKwAkpYASSsQBJWIDnX4NTlVIFvHQeEuiScCag3yiTbZa4EE+rpQg1MUoWxXyU3Ztytru9p6q9yDoHmNRvYGksgaXP1CWO//h4k7RiSsAJJWIEkrIASVgAJK5CEFUjONTh1eWcCby2jvkbJZscNdF/rHMK10jFGShjn+uiipb/aOUy0r+fWWCaieuGHiQWeQBJWQAkrgIQVSMIKJOcanLocfgZ+n0n3tqMLcohElX7k36g3UhDXGTvwsc3CGXxGqd32/gpzkNZsub7qb6PNcEx1u381tnZI2jEkYQWSsAJJWAElrAASViAJK5Cca3Dqcu4vMTOhjLK4JZbkdr1NqcZHGkNKRw/Vc8jamzO1m46zfl12yjbm0L1mV6i/cpuB6QfIHFrPFkjaMSRhBZKwAklYASWsABJWIAkrkJz3cOqzK3BjFEjaMSRhBZKwAklYASWsABJWIAkrkKD3cOpjgZtTIWnHkIQVSMIKJGEFlLACSFiBJKxAgt7DqY8Fbk6FpB1DElYgCSuQhBVQwgogYQWSsAIJegunLRa4OR0S9wxJWIEkrEASVkAJK4CEFUjCCiTpEk57LHBzOiTuGZKwAklYgSSsgBJWAAkrkIQVSNQlnPZY4OZ0wrcRkrwDJGEFkrACSVgBJawAElYgCSuQqHNCwnvEaY//Kr35TiB5B0jCCiRhBZKwAkpYASSsQBJWIGHHxO8Rpz131/8d3qyvLn/4j4sxhxMezvC/FrgFHsjfHwELvC8WuDkdC3wBJawAElYgCbeS//OvwQLviwVuTscCX0AJK4CEFUjIW+T/rHuxwPtigZvTscAXUMIKIGEFknRM/s/2KCzwvljg5nTCw0nyDpCEFUjCCiRhBZSwAkhYgaRdC/2zr8UC74sFbk7HAl9ACSuAhBVIzAr0fiAs8L7sCPzF5Qd3d5dn//BUXfbTf7i/3A3Xbzx/EZVPdaayh8s/VdRbXb/yg3++1n35eHlG12+0z+EP//wQ9XV/+dHLqCzpLysb6ehvcw7ta5bXXY+l3OZIMn8ob8QCX0AJK4CEFUjCCvRvoczEz48F3peCwJ8uP3pvenh/8DwXwFbZ5fJPcG0i1FtkEO6LhVOulzHKbm5nEtFNeKN45rLeOQxtvvd4+en8OmkT+rvdK/S3OYeeNdsbS7nNdE7HEB7O//fNn5Cn158cCkpO4KNXbw/lw6ePD4XGLPH200P56uvfVmGB92X3CGVLrFQWrq13wUAmitp66X1BfouMptfrXXHrHFKiNldyCzJU+6ubw0jHmu3OL2mT56NC4p4hCSuglARIwgokYQUaswRIWIFkXcJpz8ECn3d+M7GYUtK6lfVgdxiOEW7thPLVMULrHDJCm/N4Vv1P484l2tpfzRwCPWu2N7+kPHy6Geb3o+Ha3O5W3VpI3DMkYQWUkgBJWIEkrEBjlgAJK5Cot3DacvgOPGY8o42FF531bu0cV/VGWJb5OTCNp3sO1/He+sxfj3I/RuDFOUhrVhhLqc18PuN9+o6cxD1DElZAKQmQhBVIwgo0ZgmQsAJJeg+nPqcKfOs4INQl4UxAvVEm2S5zJZhQTxdqYJIqjP0quZFxt7q+p6m/yjkEmtdsYGssgaTN1SeM/fo1kLhnSMIKKCUBkrACSViBxiwBElYgQdfg1OWdCby1jPoaJZsdN9B9rXMI10rHGClhnOuji5b+aucw0b6eW2OZiOqFHyYWeAJJWIEkrEBjlgAJK5Cca3DqcvgZ+E8z6d52dEEOkajSj/wb9UYK4jpjBz62WTiDzyi1295fYQ7Smi3XV/1ttBmOqW73r8bWB4l7hiSsgFISIAkrkIQVaMwSIGEFknMNTl3O/SVmJpRRFnNZIsnteptSjY80BkpHD9VzyNpL203HWb8uO2Ubc+hesyvUX7nNwPQDZC6n9WyBpB1DElaYRRTWZh57IqhGSMIKJGEFGrMESFiB5FyLs59dgRujQNKOIQkrzCKisQQSWVVAElYgCSvQmCVAwgok5lqc/Vjg5lRI2jEkYYUgIRoHsZIXQBJWIAkr0JglQMIKJOZanP1Y4OZUSNoxJGGFIKG4/5WgGiEJK5CEFWjMEiBhBRJzLc5+LHBzGiTsHJKwAkpJgCSsQBJWoDFLgIQVSMw1OHWxwM1pkLBzSMIKKCUBkrACSViBxiwBElYgOdfg1MUCN6dAsiZIwgooJQGSsAJJWIHGLAESViA51+DUxX+V3pwCyZogCSuglARIwgokYQUaswRIWIHkvIdTn2QH7jhHhWRNkIQVUEoCJGEFkrACjVkCJKxAgt7CaYsF7pwSkjVBElZAKQmQhBVIwgo0ZgmQsAJJuoTTHgvcOSUka4IkrIBSEiAJK5CEFWjMEiBhBRI1EY7dnPZY4M4pIVkTJGEFlJIASViBJKxAY5YACSuQrGfiWOB9scCdU0KyJkjCCiglAZKwAklYgcYsARJWIHHPxLHA+2KBO6fkT3/6YxUfv/34UF4/vTqUt2/eHAr94WSF1x89HcqbYYxH8tVXv95kjgXelx2Bv7g83N1d7h+frq/jcNnTY/xNdwMPL64lIVOdqexheLWkVG91/cqt2afHyz1dv6V9DpcX8bcD3l+S4qS/rGxMR3+bc2hfsyWlsZTbHJPMH8orQrImSMIKJGEFkrACSViBJKxAElYgaRMWeF8KAn+6PN5PD+/DQy6ArbLw7JfkFeotMgj3xcIp18syym5uZxLRrZlRPHNZ7xyGNu8fhzuuSdqE/m73Cv1tzqFnzfbGUm4znVN/SNYESViBJKxAElYgCSuQhBVIwgoka8IC78vuEcqWWKksXIt9UEwmitp66X1BfouMptfrXXHrHNJEba7kFmSo9lc3hzEda7Y7v6RNnk9rSNQlSMIKJGEFkrACSViBJKxAElYgWZdw2nOwwOed30wspjRp3cp6sDsMxwi3dkI5GK1tDllCm/N4Vv1P4867bO2vZg4hPWu2N7+kPHy6Geb3OFyb292qWwqJugRJWIEkrEASViAJK5CEFUjCCiTqLZy2HL4DjzOe0cbCi856t3aOq3pjWJb5OTCNp3sO1/He+sxfj3I/RuDFOUhrVhhLqc18PuN97TtyEnUJkrACSViBJKxAElYgCSuQhBVI0ls4bTlV4MMdxeOAUJeEMwXqjTLJdpkrwYR6ulBDJqnC2K+SGxl3q+t7mvqrnENI85oN2RpLSNLm6hPGfn0KiboESViBJKxAElYgCSuQhBVIwgok6S2ctrwzgbeWUV+jZDPT0X2tcwjXSscYacI410cXLf3VzmFK+3pujWVKVC/8MLHAE0jCCiRhBZKwAklYgSS9h1Ofw8/An6KXofy2owtyiESVfuTfqDemIK4zduBjm4Uz+Cyldtv7K8xBWrMp2N9Gm+GY6nb/amx1IVGXIAkrkIQVSMIKJGEFkrACSViBBL2HU59zf4mZCWWUxVyWSHK73iSSglTjI42BXN4hTXPI2kvbTcdZvy5LsGxjDt1rdg31V24zZPoBMpfTeu6FRF2CJKxAElYgCSuQhBVIwgokYQUS9B5OfXYF7jitIVGXIAkrkIQVSMIKJGEFkrACSViBBL2HUx8L3Dk8JOoSJGEFkrACSViBJKxAElYgCSuQoPdw6mOBO4eHRF2CJKxAElYgCSuQhBVIwgokYQUS9B5OfSxw5/CQqEuQhBVIwgokYQWSsAJJWIEkrECC3sOpjwXuHB4SdQmSsAJJWIEkrEASrqUnJOktSMIKJOgtnLZY4M7hIVGXIAnXEpJfIwkrkIQVSMxbfBexwP96479Kbw6HRF0iF3ALc3/xNZKwAklYgSQ9E6/hXzIk6hIk6S2ctngH7hweEnWJWL5HQBJWIAkrBFH/NYckvQVJuoTTHgvcOTwk6hIkYQWSsAJJWCHfdavExx+91IYEvQeJuoTTHgvcOTwk6hIkYQWSsAJJWIEkrEBCVtgKCXoPEjURjmac9ljgzuH50x8HOVfyapDkkfzflz8/lI8++vBQfv7yYH72s0P58MOPDuXLL39ZhQXeFwvcOTwk6hIkYQWSsAJJWAElrAASViAJK5Csc0Is8L5Y4M7hIVGXIAkrkIQVSMIKKGEFkLACSViBhJ0TYoH3ZUfg0zfT8TfrcVn6TXcDydfZxd90l34LXqne6vqVW7PjNxXC9Vva55B+O2D2dapJf/RVqx39bc6hfc2WlMZSbnNMMn8o3wmJugRJWIEkrEASVkAJK4CEFUjCCiTsmPmtaYH3pSDw+atKW//Cenj2S/IK9RYZhPti4Wx9BWuS5KtlJxHdmhnFM5f1zmFoM/5q1qRN6C/7Lu2u/jbn0LNme2Mpt5nOqS8k6hIkYQWSsAJJWAElrAASViAJK5C0c8K7zwLvy+4RypZYqSxci31QTCaK2nrpfUF+i4ym1+tdcesc0kRtruQWZKj2VzeHMR1rtju/pE2eT2tI1CVIwgokYQWSsAJKWAEkrEASViBhExZ4Xw4W+Lzzm4nFlCatW1kPdofhGOHWTigHo7XNIUtocx7Pqv9p3HmXrf3VzCGkZ8325peUh083w/zkv0oPoi5BElYgCSuQhBVQwgogYQWSsALJmrDA+3L4DjzOeEYbCy86693aOa7qjWFZ5ufANJ7uOVzHe+szfz3K/RiBF+cgrVlhLKU28/mM97XvyEnUJUjCCiRhBZKwAkpYASSsQBJWIFkTFnhfThX4cEfxOCDUJeFMgXqjTLJd5kowoZ4u1JBJqjD2q+RGxt3q+p6m/irnENK8ZkO2xhKStLn6hLFfn0KiLkESViAJK5CEFVDCCiBhBZKwAsm6hNOedybw1jLqa5RsZjq6r3UO4VrpGCNNGOf66KKlv9o5TGlfz62xTInqhR8mFngCSVgBJawAElYgCSuQqEs47Tn8DNx/lb6nv8IcpDWbgv1ttBmOqW73r8ZWFxJ1CZKwAklYgSSsgBJWAAkrkIQVSNQlnPac+0vMTCijLOayRJLb9SaRFKQaH2kM5PIOaZpD1l7abjrO+nVZgmUbc+hes2uov3KbIdMPkLmc1nMvJOoSJGEFkrACSVgBJawAElYgCSuQqEs47dkVuOO0hkRdgiSsQBJWIAkroIQVQMIKJGEFEjXhX2L2xQJ3Dg+JugRJWIEkrEASVkAJK4CEFUjCCiRrwgLviwXuHB4SdQmSsAJJWIEkrIASVgAJK5CEFUjWhAXeFwvcOTwk6hIkYQWSsAJJWAElrAASViAJK5Csc0Is8L5Y4M7hIVGXIAkr/KWE5B1ACSuAhBVIwgok7Jg5FnhPLpf/BA8NWv9Nxtm2AAAAAElFTkSuQmCC" alt="" />
方法 2 使用子查询的方式查询
1.     <resultMap id="peopleResultMap" type="People">

2.         <id property="id" column="id" />

3.         <result property="name" column="name" />

4.         <collection property="qqs" ofType="string" javaType="list">

5.             <result column="qq" />

6.         </collection>

7.     </resultMap>

8.

9.     <select id="selectPeopleById" resultMap="peopleResultMap">

10.         select p.*,pq.qq from

11.         people p left join  people_qq pq on p.id = pq.people_id

12.         where p.id = #{id}

13.     </select>
子查询，就是在集合列表中调用另一个查询，进行数据赋值。
优点：可以使用数据库自带的分页函数
缺点：查询数据需要多次调用子查询进行集合字段数据查询。如果是大数据量查询，将会需要多次调用子查询sql。
mybatis默认使用懒加载的方式进行集合的子查询。存在问题。
可以查看下面这篇文章：mybatis问题解决
Springmvc+mybatis,mybatis配置延迟加载时，json序列化异常

https://ask.****.net/questions/344738?sort=comments_count

实体类有一个属性是其它实体类的类型，mybatis默认使用了 延迟加载，导致在处理这个类的时候某些属性不能被序列化，因此造成了上述原因

https://www.oschina.net/question/2312022_2232071

最近做项目时，使用了mybatis级联查询，配置了懒加载模式，结果通过springMvc返回json时报的错。报错如下：

https://blog.****.net/qq_33548914/article/details/79991280

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