mybatis 一对多：用户与角色

pom.xml 依赖

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
  <modelVersion>4.0.0modelVersion>
  <groupId>com.fzgroupId>
  <artifactId>demoartifactId>
  <packaging>warpackaging>
  <version>1.0version>
  <name>demo Maven Webappname>
  <url>http://maven.apache.orgurl>
  <dependencies>

    <dependency>
      <groupId>junitgroupId>
      <artifactId>junitartifactId>
      <version>4.12version>
      <scope>testscope>
    dependency>
    <dependency>
      <groupId>org.mybatisgroupId>
      <artifactId>mybatisartifactId>
      <version>3.4.1version>
    dependency>

    <dependency>
      <groupId>mysqlgroupId>
      <artifactId>mysql-connector-javaartifactId>
      <version>5.1.40version>
    dependency>

    <dependency>
      <groupId>org.projectlombokgroupId>
      <artifactId>lombokartifactId>
      <version>1.16.2version>
    dependency>

    <dependency>
      <groupId>javax.servletgroupId>
      <artifactId>javax.servlet-apiartifactId>
      <version>3.1.0version>
      <scope>providedscope>
    dependency>

    <dependency>
      <groupId>javax.servletgroupId>
      <artifactId>jstlartifactId>
      <version>1.2version>
    dependency>

  dependencies>
  <build>
    <finalName>${project.artifactId}finalName>
    <sourceDirectory>src/main/javasourceDirectory>
    <testSourceDirectory>src/test/javatestSourceDirectory>
    <resources>
      <resource>
        <directory>src/main/javadirectory>
        <includes>
          <include>**/*.xmlinclude>
        includes>
      resource>
      <resource>
        <directory>src/main/resourcesdirectory>
        <includes>
          <include>**/*.xmlinclude>
          <include>**/*.propertiesinclude>
        includes>
      resource>
    resources>
  build>
project>

2:resources 相关配置
—–conf.xml

<configuration>
    <properties resource="db.properties"/>
    <typeAliases>
        <package name="com.fz.model">package>
    typeAliases>
    <environments default="development">
        <environment id="development">
            <transactionManager type="JDBC"/>
            <dataSource type="POOLED">
                <property name="driver" value="${db.driver}"/>
                <property name="url" value="${db.url}"/>
                <property name="username" value="${db.username}"/>
                <property name="password" value="${db.password}"/>
            dataSource>
        environment>
    environments>
    <mappers>
        <package name="com.fz.mapper"/>
    mappers>
configuration>

—db.properties
–即mysql 数据库配置

db.driver=com.mysql.jdbc.Driver
db.url=jdbc:mysql://localhost:3306/db?useUnicode=true&characterEncoding=utf8&useSSL=true
db.username=root
db.password=

3:创建目录和类

4:model>User类：

import lombok.Data;
import java.util.List;

/**
 * Created by Sir.Cui on 2017/1/13 12:01.
 */
@Data
public class User {
    private int id;
    private String name;
    private String pass;
    private List roles;
}

model>Role类

package com.fz.model;
import lombok.Data;
/**
 * Created by Sir.Cui on 2017/1/13 14:02.
 */
@Data
public class Role {
    private int id;
    private String name;
    //private User user;
}

5;Mapper>UserMapper接口类

package com.fz.mapper;

import com.fz.model.User;

/**
 * Created by Administrator on 2017/1/11.
 */
public interface UserMapper {
    public User findbyId(int id);
}

–UserMapper.xml

<mapper namespace="com.fz.mapper.UserMapper">
    <resultMap id="ur" type="user">
        <id property="id" column="id"/>
        <result column="name" property="name"/>
        <result column="pass" property="pass"/>
        <collection property="roles" column="id" select="com.fz.mapper.RoleMapper.byId"/>
    resultMap>
    <select id="findbyId" parameterType="int" resultMap="ur">
        select * from db_user where id=#{id};
    select>

mapper>

6:–Role 接口类

package com.fz.mapper;

import com.fz.model.Role;

/**
 * Created by Administrator on 2017/1/11.
 */
public interface RoleMapper {
   public Role byId(int i);
   //public Role rId(int i);
}

–RoleMapper.xml

<mapper namespace="com.fz.mapper.RoleMapper">
    <resultMap id="rr" type="role">
        <id property="id" column="rid"/>
        <result property="name" column="rname"/>
    resultMap>
    <select id="byId" parameterType="int" resultMap="rr">
        select * from db_role where uid=#{id};
    select>
mapper>

7:–mybatis>MyBatisUtil类

package com.fz.mybatis;

        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 java.io.IOException;
        import java.io.Reader;

/**
 * Created by Administrator on 2017/1/11.
 */
public class MyBatisUtil {
    private final static SqlSessionFactory sf;
    private final static SqlSession session;

    static {
        String resource = "conf.xml";
        Reader reader = null;
        try {
            reader = Resources.getResourceAsReader(resource);
        } catch (IOException e) {
            System.out.println(e.getMessage());
        }
        sf = new SqlSessionFactoryBuilder().build(reader);
        session = sf.openSession();
    }

    public static SqlSessionFactory getSqlSessionFactory() {
        return sf;
    }

    public static SqlSession getSqlSession() {
        return session;
    }
}

8：自己在创建个测试类就可以了