Mybatis-6-表间关系（一对一、一对多、多对多）

一、一对一关系

两张表：

-- 公民表
-- 身份证表

-- 表间关系：一对一
-- 一个公民只有一个身份证
-- 一个身份证只属于一个公民

-- 身份证表
DROP TABLE IF EXISTS t_card;

CREATE TABLE t_card(
	cid INT PRIMARY KEY auto_increment,
	cnum VARCHAR(20)
) ENGINE=INNODB DEFAULT CHARSET=utf8;

INSERT INTO t_card VALUES(NULL, '123456-1');
INSERT INTO t_card VALUES(NULL, '123456-2');
INSERT INTO t_card VALUES(NULL, '123456-3');

-- 公民表
DROP TABLE IF EXISTS t_person;

CREATE TABLE t_person(
	pid INT PRIMARY KEY auto_increment,
	name VARCHAR(10),
	sex VARCHAR(1),
	age INT,
	birthday date,
	cid INT,
	FOREIGN KEY t_person(cid) REFERENCES t_card(cid)
) ENGINE=INNODB DEFAULT CHARSET=utf8;

INSERT INTO t_person VALUES(NULL, 'Person1', '男', 11, '1997-6-1', 1);
INSERT INTO t_person VALUES(NULL, 'Person2', '女', 12, '1997-6-2', 2);
INSERT INTO t_person VALUES(NULL, 'Person3', '女', 13, '1997-6-3', 3);

实体类：

公民：Person

package com.seven.entity;

import java.io.Serializable;
import java.util.Date;
import java.util.List;

public class Person implements Serializable {
    private Integer pid;
    private String name;
    private String sex;
    private Integer age;
    private Date birthday;
    private Integer cid;

    // 一对一
    private Card card;

    @Override
    public String toString() {
        return "Person{" +
                "pid=" + pid +
                ", name='" + name + '\'' +
                ", sex='" + sex + '\'' +
                ", age=" + age +
                ", birthday=" + birthday +
                ", cid=" + cid +
                ", card=" + card +
                '}';
    }

    public Card getCard() {
        return card;
    }

    public void setCard(Card card) {
        this.card = card;
    }

    public Integer getPid() {
        return pid;
    }

    public void setPid(Integer pid) {
        this.pid = pid;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getSex() {
        return sex;
    }

    public void setSex(String sex) {
        this.sex = sex;
    }

    public Integer getAge() {
        return age;
    }

    public void setAge(Integer age) {
        this.age = age;
    }

    public Date getBirthday() {
        return birthday;
    }

    public void setBirthday(Date birthday) {
        this.birthday = birthday;
    }

    public Integer getCid() {
        return cid;
    }

    public void setCid(Integer cid) {
        this.cid = cid;
    }
}

身份证：Card

package com.seven.entity;

import java.io.Serializable;

public class Card implements Serializable {
    private Integer cid;
    private String cnum;

    @Override
    public String toString() {
        return "Card{" +
                "cid=" + cid +
                ", cnum='" + cnum + '\'' +
                '}';
    }

    public Integer getCid() {
        return cid;
    }

    public void setCid(Integer cid) {
        this.cid = cid;
    }

    public String getCnum() {
        return cnum;
    }

    public void setCnum(String cnum) {
        this.cnum = cnum;
    }
}

映射文件

PersonMapper.xml文件：

	<resultMap id="personMap" type="com.seven.entity.Person">
        <id property="pid" column="pid"/>
        <result property="name" column="name"/>
        <result property="sex" column="sex"/>
        <result property="age" column="age"/>
        <result property="birthday" column="birthday"/>
        <result property="cid" column="cid"/>
    </resultMap>

	<!-- 这个resultMap继承了上面的id为personMap的resultMap -->
    <resultMap id="pcMap" type="com.seven.entity.Person" extends="personMap">
    	<!-- 配置一对一 -->
        <association property="card" column="cid" javaType="com.seven.entity.Card">
            <id property="cid" column="cid"/>
            <result property="cnum" column="cnum"/>
        </association>
    </resultMap>
    
	<select id="findDetailed" resultMap="pcMap">
        select p.*, c.cnum from t_person p, t_card c where p.cid=c.cid
    </select>

映射接口

PersonMapper接口：

package com.seven.mapper;

import com.seven.entity.Person;

import java.util.List;

public interface PersonMapper {
    List<Person> findAll();

    /**
     * 演示一对一关系
     * @return
     */
    List<Person> findDetailed();
}

测试类

TestPerson测试类：

import com.seven.entity.Person;
import com.seven.mapper.PersonMapper;
import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;
import org.junit.After;
import org.junit.Before;
import org.junit.Test;

import java.io.IOException;
import java.io.InputStream;
import java.util.List;

public class TestPerson {
    private InputStream in;
    private SqlSession sqlSession;
    private PersonMapper mapper;

    @Before
    public void init() {
        try {
            in = Resources.getResourceAsStream("mybatis.config.xml");
            SqlSessionFactory factory = new SqlSessionFactoryBuilder().build(in);
            sqlSession = factory.openSession();
            mapper = sqlSession.getMapper(PersonMapper.class);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    @After
    public void close() throws IOException {
        sqlSession.close();
        in.close();
    }

    @Test
    public void testFindAll() {
        List<Person> all = mapper.findAll();
        for (Person person : all) {
            System.out.println(person);
        }
    }

    /**
     * 测试一对一
     */
    @Test
    public void testFindDetailed() {
        List<Person> persons = mapper.findDetailed();
        for (Person person : persons) {
            System.out.println(person);
        }
    }
}

结果

二、一对多关系

两张表

-- 公民表：在一对一中创建
-- 订单表

-- 表间关系：一对多
-- 一个公民可以有多个订单
-- 一个订单只能属于一个公民

-- 订单表
DROP TABLE IF EXISTS t_order;

CREATE TABLE t_order(
	oid INT PRIMARY KEY auto_increment,
	pid INT,
	odate TIMESTAMP,
	price DOUBLE,
	FOREIGN KEY t_order(pid) REFERENCES t_person(pid)
) ENGINE=INNODB DEFAULT CHARSET=utf8;

DELETE FROM t_order;

INSERT INTO t_order VALUES(NULL, 1, NOW(), 11.5);
INSERT INTO t_order VALUES(NULL, 1, NOW(), 12.5);
INSERT INTO t_order VALUES(NULL, 1, NOW(), 13.5);

INSERT INTO t_order VALUES(NULL, 2, NOW(), 24.5);
INSERT INTO t_order VALUES(NULL, 2, NOW(), 25.5);

实体类

订单：Order

package com.seven.entity;

import java.io.Serializable;
import java.util.Date;

public class Order implements Serializable {
    private Integer oid;
    private Integer pid;
    private Date odate;
    private Double price;

    public Integer getOid() {
        return oid;
    }

    public void setOid(Integer oid) {
        this.oid = oid;
    }

    public Integer getPid() {
        return pid;
    }

    public void setPid(Integer pid) {
        this.pid = pid;
    }

    public Date getOdate() {
        return odate;
    }

    public void setOdate(Date odate) {
        this.odate = odate;
    }

    public Double getPrice() {
        return price;
    }

    public void setPrice(Double price) {
        this.price = price;
    }

    @Override
    public String toString() {
        return "Order{" +
                "oid=" + oid +
                ", pid=" + pid +
                ", odate=" + odate +
                ", price=" + price +
                '}';
    }
}

公民：Person
添加属性和getter，setter方法

// 一对多
    private List<Order> orders;
    
    public List<Order> getOrders() {
        return orders;
    }

    public void setOrders(List<Order> orders) {
        this.orders = orders;
    }

映射文件

PersonMapper.xml文件：

<?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.seven.mapper.PersonMapper">
    <resultMap id="personMap" type="com.seven.entity.Person">
        <id property="pid" column="pid"/>
        <result property="name" column="name"/>
        <result property="sex" column="sex"/>
        <result property="age" column="age"/>
        <result property="birthday" column="birthday"/>
        <result property="cid" column="cid"/>
    </resultMap>

    <resultMap id="pcMap" type="com.seven.entity.Person" extends="personMap">
        <association property="card" column="cid" javaType="com.seven.entity.Card">
            <id property="cid" column="cid"/>
            <result property="cnum" column="cnum"/>
        </association>
    </resultMap>

	<!-- 配置一对多的resultMap -->
    <resultMap id="poMap" type="com.seven.entity.Person" extends="personMap">
    	<!-- property对应实体类的属性，ofType对应该属性的实体类 -->
        <collection property="orders" ofType="com.seven.entity.Order">
            <id property="oid" column="oid"/>
            <result property="pid" column="pid"/>
            <result property="odate" column="odate"/>
            <result property="price" column="price"/>
        </collection>
    </resultMap>

    <select id="findAll" resultMap="personMap">
        select * from t_person
    </select>
    
    <select id="findDetailed" resultMap="pcMap">
        select p.*, c.cnum from t_person p, t_card c where p.cid=c.cid
    </select>

	<!-- 左连接查询person和order的结果 -->
    <select id="findPersonAndOrder" resultMap="poMap">
        SELECT p.*, o.oid, o.odate, o.price
        FROM t_person p LEFT JOIN t_order o ON (p.pid=o.pid);
    </select>
</mapper>

映射接口

PersonMapper接口：

package com.seven.mapper;

import com.seven.entity.Person;

import java.util.List;

public interface PersonMapper {
    List<Person> findAll();

    /**
     * 一对一关系
     * @return
     */
    List<Person> findDetailed();

    /**
     * 一对多关系
     * @return
     */
    List<Person> findPersonAndOrder();
}

测试类

TestPerson测试类：

import com.seven.entity.Person;
import com.seven.mapper.PersonMapper;
import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;
import org.junit.After;
import org.junit.Before;
import org.junit.Test;

import java.io.IOException;
import java.io.InputStream;
import java.util.List;

public class TestPerson {
    private InputStream in;
    private SqlSession sqlSession;
    private PersonMapper mapper;

    @Before
    public void init() {
        try {
            in = Resources.getResourceAsStream("mybatis.config.xml");
            SqlSessionFactory factory = new SqlSessionFactoryBuilder().build(in);
            sqlSession = factory.openSession();
            mapper = sqlSession.getMapper(PersonMapper.class);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    @After
    public void close() throws IOException {
        sqlSession.close();
        in.close();
    }

    @Test
    public void testFindAll() {
        List<Person> all = mapper.findAll();
        for (Person person : all) {
            System.out.println(person);
        }
    }

    /**
     * 测试一对一
     */
    @Test
    public void testFindDetailed() {
        List<Person> persons = mapper.findDetailed();
        for (Person person : persons) {
            System.out.println(person);
        }
    }

    /**
     * 测试一对多
     */
    @Test
    public void testFindPersonAndOrder() {
        List<Person> persons = mapper.findPersonAndOrder();
        for (Person person : persons) {
            System.out.println("-----------------------------------------------------------------------");
            System.out.println(person);
            System.out.println(person.getOrders());
        }
    }
}

结果

三、多对多关系

三张表

-- 订单表：在一对多中创建了
-- 商品表
-- 中间表

-- 表间关系：多对多
-- 一个订单下可以有多个商品
-- 一个商品可以属于多个订单

-- 商品表
DROP TABLE IF EXISTS t_goods;

CREATE TABLE t_goods(
	gid VARCHAR(20),
	gname VARCHAR(100),
	gprice DOUBLE DEFAULT 0,
	gdesc VARCHAR(200),
	gstatus INT DEFAULT 1,
	CONSTRAINT goods_pk PRIMARY KEY (gid)
) ENGINE=INNODB DEFAULT CHARSET=utf8;

INSERT INTO t_goods VALUES('wy-1', '卫衣1', 11.9, '卫衣1-desc', 1);
INSERT INTO t_goods VALUES('wy-2', '卫衣2', 22.9, '卫衣2-desc', 1);
INSERT INTO t_goods VALUES('wy-3', '卫衣3', 33.9, '卫衣3-desc', 1);
INSERT INTO t_goods VALUES('nzk-1', '牛仔裤1', 111.9, '牛仔裤1-desc', 1);
INSERT INTO t_goods VALUES('nzk-2', '牛仔裤2', 222.9, '牛仔裤2-desc', 1);
INSERT INTO t_goods VALUES('nzk-3', '牛仔裤3', 333.9, '牛仔裤3-desc', 1);
INSERT INTO t_goods VALUES('xz-1', '鞋子1', 230.9, '鞋子1-desc', 1);
INSERT INTO t_goods VALUES('xz-2', '鞋子2', 120.9, '鞋子2-desc', 1);
INSERT INTO t_goods VALUES('xz-3', '鞋子3', 389.9, '鞋子3-desc', 1);
INSERT INTO t_goods VALUES('wz-1', '袜子1', 9.9, '袜子1-desc', 1);
INSERT INTO t_goods VALUES('wz-2', '袜子2', 5.9, '袜子2-desc', 1);
INSERT INTO t_goods VALUES('wz-3', '袜子3', 11.9, '袜子3-desc', 1);
INSERT INTO t_goods VALUES('yj-1', '眼镜1', 199.9, '眼镜1-desc', 1);
INSERT INTO t_goods VALUES('yj-2', '眼镜2', 150.9, '眼镜2-desc', 1);
INSERT INTO t_goods VALUES('yj-3', '眼镜3', 299.9, '眼镜3-desc', 1);
INSERT INTO t_goods VALUES('mf-1', '棉服1', 350.9, '棉服1-desc', 1);
INSERT INTO t_goods VALUES('mf-2', '棉服2', 359.9, '棉服2-desc', 1);
INSERT INTO t_goods VALUES('mf-3', '棉服3', 266.9, '棉服3-desc', 1);
INSERT INTO t_goods VALUES('jk-1', '夹克1', 159.9, '夹克1-desc', 1);
INSERT INTO t_goods VALUES('jk-2', '夹克2', 179.9, '夹克2-desc', 1);
INSERT INTO t_goods VALUES('jk-3', '夹克3', 199.9, '夹克3-desc', 1);
INSERT INTO t_goods VALUES('xxk-1', '休闲裤1', 119.9, '休闲裤1-desc', 1);
INSERT INTO t_goods VALUES('xxk-2', '休闲裤2', 189.9, '休闲裤2-desc', 1);
INSERT INTO t_goods VALUES('xxk-3', '休闲裤3', 129.9, '休闲裤3-desc', 1);

-- 中间表
DROP TABLE IF EXISTS t_order_goods;

CREATE TABLE t_order_goods(
	oid INT,
	gid VARCHAR(20),
  CONSTRAINT order_goods_pk PRIMARY KEY (oid, gid),
	CONSTRAINT og_o_fk FOREIGN KEY t_order_goods(oid) REFERENCES t_order(oid),
	CONSTRAINT og_f_fk FOREIGN KEY t_order_goods(gid) REFERENCES t_goods(gid)
) ENGINE=INNODB DEFAULT CHARSET=utf8;

INSERT INTO t_order_goods VALUES(1, 'wy-1');
INSERT INTO t_order_goods VALUES(1, 'wy-2');
INSERT INTO t_order_goods VALUES(1, 'xxk-3');
INSERT INTO t_order_goods VALUES(2, 'jk-1');
INSERT INTO t_order_goods VALUES(2, 'wy-1');
INSERT INTO t_order_goods VALUES(3, 'wz-1');
INSERT INTO t_order_goods VALUES(3, 'wz-2');

实现：
1.查询商品，可以得到购买过它的订单信息
2.查询订单，可以得到购买的商品信息

1.查询商品，可以得到购买过它的订单信息

实体类

商品：Goods

package com.seven.entity;

import java.io.Serializable;
import java.util.List;

public class Goods implements Serializable {
    private String gid;
    private String gname;
    private Double gprice;
    private String gdesc;
    private Integer gstatus;

    //多对多
    private List<Order> orders;

    public List<Order> getOrders() {
        return orders;
    }

    public void setOrders(List<Order> orders) {
        this.orders = orders;
    }

    @Override
    public String toString() {
        return "Goods{" +
                "gid='" + gid + '\'' +
                ", gname='" + gname + '\'' +
                ", gprice=" + gprice +
                ", gdesc='" + gdesc + '\'' +
                ", gstatus=" + gstatus +
                '}';
    }

    public String getGid() {
        return gid;
    }

    public void setGid(String gid) {
        this.gid = gid;
    }

    public String getGname() {
        return gname;
    }

    public void setGname(String gname) {
        this.gname = gname;
    }

    public Double getGprice() {
        return gprice;
    }

    public void setGprice(Double gprice) {
        this.gprice = gprice;
    }

    public String getGdesc() {
        return gdesc;
    }

    public void setGdesc(String gdesc) {
        this.gdesc = gdesc;
    }

    public Integer getGstatus() {
        return gstatus;
    }

    public void setGstatus(Integer gstatus) {
        this.gstatus = gstatus;
    }
}

映射文件

<?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.seven.mapper.GoodsMapper">
    <resultMap id="goodsMap" type="com.seven.entity.Goods">
        <id property="gid" column="gid"/>
        <result property="gname" column="gname"/>
        <result property="gprice" column="gprice"/>
        <result property="gdesc" column="gdesc"/>
        <result property="gstatus" column="gstatus"/>
    </resultMap>

    <resultMap id="goMap" type="com.seven.entity.Goods" extends="goodsMap">
        <collection property="orders" ofType="com.seven.entity.Order">
            <id property="oid" column="oid"/>
            <result property="pid" column="pid"/>
            <result property="odate" column="odate"/>
            <result property="price" column="price"/>
        </collection>
    </resultMap>

    <select id="findAll" resultMap="goodsMap">
        select * from t_goods
    </select>

	<!-- 三张表查询，以商品表为主表的左连接查询 -->
    <select id="findGoodsOrder" resultMap="goMap">
        SELECT g.*, o.* FROM t_goods g
        LEFT JOIN t_order_goods og ON og.gid=g.gid
        LEFT JOIN t_order o ON og.oid=o.oid
    </select>
</mapper>

映射接口

package com.seven.mapper;

import com.seven.entity.Goods;

import java.util.List;

public interface GoodsMapper {
    List<Goods> findAll();

    List<Goods> findGoodsOrder();
}

测试类

GoodsTest测试类：

import com.seven.entity.Goods;
import com.seven.entity.Order;
import com.seven.mapper.GoodsMapper;
import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;
import org.junit.After;
import org.junit.Before;
import org.junit.Test;

import java.io.IOException;
import java.io.InputStream;
import java.util.List;

public class TestGoods {
    private InputStream in;
    private SqlSession sqlSession;
    private GoodsMapper mapper;

    @Before
    public void init() {
        try {
            in = Resources.getResourceAsStream("mybatis.config.xml");
            SqlSessionFactory factory = new SqlSessionFactoryBuilder().build(in);
            sqlSession = factory.openSession();
            mapper = sqlSession.getMapper(GoodsMapper.class);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    @After
    public void close() throws IOException {
        sqlSession.close();
        in.close();
    }

    @Test
    public void testFindAll() {
        List<Goods> all = mapper.findAll();
        for (Goods goods : all) {
            System.out.println(goods);
        }
    }

    @Test
    public void testFindGoodsOrder() {
        List<Goods> goodsOrder = mapper.findGoodsOrder();
        for (Goods goods : goodsOrder) {
            System.out.println("-------------------------------------");
            System.out.println(goods);
            for (Order order : goods.getOrders()) {
                System.out.println(order);
            }
        }
    }
}

结果

2.查询订单，可以得到购买的商品信息

实体类

Order：

package com.seven.entity;

import java.io.Serializable;
import java.util.Date;
import java.util.List;

public class Order implements Serializable {
    private Integer oid;
    private Integer pid;
    private Date odate;
    private Double price;

    //多对多
    private List<Goods> goods;

    public List<Goods> getGoods() {
        return goods;
    }

    public void setGoods(List<Goods> goods) {
        this.goods = goods;
    }

    public Integer getOid() {
        return oid;
    }

    public void setOid(Integer oid) {
        this.oid = oid;
    }

    public Integer getPid() {
        return pid;
    }

    public void setPid(Integer pid) {
        this.pid = pid;
    }

    public Date getOdate() {
        return odate;
    }

    public void setOdate(Date odate) {
        this.odate = odate;
    }

    public Double getPrice() {
        return price;
    }

    public void setPrice(Double price) {
        this.price = price;
    }

    @Override
    public String toString() {
        return "Order{" +
                "oid=" + oid +
                ", pid=" + pid +
                ", odate=" + odate +
                ", price=" + price +
                '}';
    }
}

映射文件

<?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.seven.mapper.OrderMapper">
    <resultMap id="orderMap" type="com.seven.entity.Order">
        <id property="oid" column="oid"/>
        <result property="pid" column="pid"/>
        <result property="odate" column="odate"/>
        <result property="price" column="price"/>
    </resultMap>

    <resultMap id="ogMap" type="com.seven.entity.Order" extends="orderMap">
        <collection property="goods" ofType="com.seven.entity.Goods">
            <id property="gid" column="gid"/>
            <result property="gname" column="gname"/>
            <result property="gprice" column="gprice"/>
            <result property="gdesc" column="gdesc"/>
            <result property="gstatus" column="gstatus"/>
        </collection>
    </resultMap>

    <select id="findAll" resultMap="orderMap">
        select * from t_order
    </select>

	<!-- 三张表查询，以订单表为主表的左连接查询 -->
    <select id="findOrderGoods" resultMap="ogMap">
        SELECT o.*, g.* FROM t_order o
        LEFT JOIN t_order_goods og ON og.oid=o.oid
        LEFT JOIN t_goods g ON og.gid=g.gid;
    </select>
</mapper>

映射接口

package com.seven.mapper;

import com.seven.entity.Order;

import java.util.List;

public interface OrderMapper {
    List<Order> findAll();

    List<Order> findOrderGoods();
}

测试类

import com.seven.entity.Goods;
import com.seven.entity.Order;
import com.seven.mapper.OrderMapper;
import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;
import org.junit.After;
import org.junit.Before;
import org.junit.Test;

import java.io.IOException;
import java.io.InputStream;
import java.util.List;

public class TestOrder {
    private InputStream in;
    private SqlSession sqlSession;
    private OrderMapper mapper;

    @Before
    public void init() {
        try {
            in = Resources.getResourceAsStream("mybatis.config.xml");
            SqlSessionFactory factory = new SqlSessionFactoryBuilder().build(in);
            sqlSession = factory.openSession();
            mapper = sqlSession.getMapper(OrderMapper.class);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    @After
    public void close() throws IOException {
        sqlSession.close();
        in.close();
    }

    @Test
    public void findAll() {
        List<Order> all = mapper.findAll();
        for (Order order : all) {
            System.out.println(order);
        }
    }

    @Test
    public void findOrderGoods() {
        List<Order> orders = mapper.findOrderGoods();
        for (Order order : orders) {
            System.out.println("-----------------------------------------------------------------");
            System.out.println(order);
            for (Goods good : order.getGoods()) {
                System.out.println(good);
            }
        }
    }
}

结果

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更新时间：2020-1-15