mybatis模糊查询、分页和别名配置的方法

select * from user where username like "%" #{name} "%"

select * from user where username like "%${value}%"

<!--concat拼接字符串 mysql独有的函数-->
select * from user where username like concat("%",#{username},"%")

<typeAlias type="com.lu.pojo.User" alias="User"/>

<typeAliases>
 <package name="com.lu.pojo"/>
</typeAliases>

@Alias("user")
public class User{
 ...
}

<select id="getUserById" resultType="com.lu.pojo.User">
  select id,username, pwd as password from user where id = #{id}
 </select>

<!--结果集映射-->
 <resultMap id="userMap" type="com.lu.pojo.User">
  <!--property是实体类中的属性，column是数据库中的字段 -->
  <result property="password" column="pwd" />
 </resultMap>

 <select id="getUserById" resultMap="userMap">
  select id,username, pwd from user where id = #{id}
 </select>

//使用limit实现分页
 List<User> getUserByLimit(Map<String,Integer> map);

<select id="getUserByLimit" parameterType="map" resultType="com.lu.pojo.User">
  select * from user limit #{offset}, #{pageSize}
 </select>

@Test
 public void getUserByLimit(){
  SqlSession sqlSession = MybatisUtils.getSqlSession();
  UserMapper userMapper = sqlSession.getMapper(UserMapper.class);

  Map<String, Integer> map = new HashMap<String, Integer>();
  map.put("offset",1);
  map.put("pageSize",2);
  List<User> users = userMapper.getUserByLimit(map);
  for (User user : users) {
   System.out.println(user);
  }
  sqlSession.close();
 }

 //通过RowBounds实现分页
 List<User> getUserByRowBounds(RowBounds rowBounds);

<select id="getUserByRowBounds" resultType="com.lu.pojo.User">
  select * from user
 </select>

 @Test
 public void getUserByRowBounds(){
  SqlSession sqlSession = MybatisUtils.getSqlSession();
  UserMapper userMapper = sqlSession.getMapper(UserMapper.class);

  RowBounds rowBounds = new RowBounds(1, 2);
  List<User> users = userMapper.getUserByRowBounds(rowBounds);

  for (User user : users) {
   System.out.println(user);
  }
  sqlSession.close();
 }

 <dependency>
   <groupId>com.github.pagehelper</groupId>
   <artifactId>pagehelper</artifactId>
   <version>4.1.6</version>
  </dependency>

<plugins>
  <plugin interceptor="com.github.pagehelper.PageHelper">
    <property name="dialect" value="mysql"/>
  </plugin>
</plugins>

 //通过pagehelper分页插件实现
  List<User> getUserByPageHelper();

 <select id="getUserByPageHelper" resultType="com.lu.pojo.User">
    select * from user
  </select>

import com.github.pagehelper.PageHelper;

 @Test
  public void getUserByPageHelper(){
    SqlSession sqlSession = MybatisUtils.getSqlSession();
    UserMapper userMapper = sqlSession.getMapper(UserMapper.class);

    PageHelper.startPage(1,3);
    List<User> users = userMapper.getUserByPageHelper();
    for (User user : users) {
      System.out.println(user);
    }
    sqlSession.close();
  }

<dependency>
  <groupId>org.projectlombok</groupId>
  <artifactId>lombok</artifactId>
  <version>1.18.12</version>
  <scope>provided</scope>
</dependency>