自定义全局操作

• ​​官方文档​​
• ​​官方文档​​
• ​​官方案例​​
• 定义sql

public class FindOne extends AbstractMethod {

    @Override
    public MappedStatement injectMappedStatement(Class<?> mapperClass, Class<?> modelClass, TableInfo tableInfo) {
        /* 执行 SQL ，动态 SQL 参考类 SqlMethod */
        String sql = "select * from " + tableInfo.getTableName()
                + " where " + tableInfo.getKeyColumn() + "=#{" + tableInfo.getKeyProperty() + "}";
        /* mapper 接口方法名一致 */
        String method = "findOne";
        SqlSource sqlSource = languageDriver.createSqlSource(configuration, sql, modelClass);
        return addSelectMappedStatementForTable(mapperClass, method, sqlSource, tableInfo);
    }
}

• 自定义sql注入

public class MySqlInjector extends DefaultSqlInjector {

    @Override
    public List<AbstractMethod> getMethodList(Class<?> mapperClass, TableInfo tableInfo) {
        List<AbstractMethod> methodList = super.getMethodList(mapperClass, tableInfo);
        //增加自定义方法
        methodList.add(new DeleteAll());
        methodList.add(new FindOne());
        /**
         * 以下 3 个为内置选装件
         * 头 2 个支持字段筛选函数
         */
        // 例: 不要指定了 update 填充的字段
        methodList.add(new InsertBatchSomeColumn(i -> i.getFieldFill() != FieldFill.UPDATE));
        methodList.add(new AlwaysUpdateSomeColumnById());
        methodList.add(new LogicDeleteByIdWithFill());
        return methodList;
    }
}

• 定义到BaseMapper

public interface MyBaseMapper<T> extends BaseMapper<T> {

    /* ↓↓↓↓↓↓↓↓↓↓↓↓↓↓  ↓↓↓↓↓↓↓↓↓↓↓↓↓↓ */

    /**
     * 以下定义的 4个 default method, copy from {@link com.baomidou.mybatisplus.extension.toolkit.ChainWrappers}
     */
    default QueryChainWrapper<T> queryChain() {
        return new QueryChainWrapper<>(this);
    }

    default LambdaQueryChainWrapper<T> lambdaQueryChain() {
        return new LambdaQueryChainWrapper<>(this);
    }

    default UpdateChainWrapper<T> updateChain() {
        return new UpdateChainWrapper<>(this);
    }

    default LambdaUpdateChainWrapper<T> lambdaUpdateChain() {
        return new LambdaUpdateChainWrapper<>(this);
    }

    /**
     * 以下定义的 4个 method 其中 3 个是内置的选装件
     */
    int insertBatchSomeColumn(List<T> entityList);

    int alwaysUpdateSomeColumnById(@Param(Constants.ENTITY) T entity);

    int deleteByIdWithFill(T entity);

    /**
     * 以下为自己自定义
     */
    T findOne(Serializable id);

    int deleteAll();
}

• 测试

@Slf4j
@SpringBootTest
public class InjectorTest {

    @Resource
    private StudentMapper studentMapper;

    /**
     * 插入2条数据
     * INSERT INTO STUDENT ( ID, NAME, AGE ) VALUES ( ?, ?, ? )
     * 1549911999816278017(Long), 小明0号(String), 0(Integer)
     *
     * INSERT INTO STUDENT ( ID, NAME, AGE ) VALUES ( ?, ?, ? )
     * 1549911999887581185(Long), 小明1号(String), 1(Integer)
     */
    @Test
    public void test() {
        log.error("--------------------------------------insert-------------------------------------------------------");
        List<Long> ids = Lists.newArrayList();
        for (int i = 0; i < 2; i++) {
            Student student = new Student("小明" + i + "号", i);
            studentMapper.insert(student);
            ids.add(student.getId());
        }
    }

    /**
     * 插入18条数据
     * INSERT INTO STUDENT (ID,NAME,AGE) VALUES (?,?,?) , (?,?,?) , (?,?,?) , (?,?,?) , (?,?,?) , (?,?,?) , (?,?,?) , (?,?,?) , (?,?,?) , (?,?,?) , (?,?,?) , (?,?,?) , (?,?,?) , (?,?,?) , (?,?,?) , (?,?,?) , (?,?,?) , (?,?,?)
     * 1549912388825489409(Long), 小明2号(String), 2(Integer), 1549912388825489410(Long), 小明3号(String), 3(Integer), 1549912388825489411(Long), 小明4号(String), 4(Integer), 1549912388825489412(Long), 小明5号(String), 5(Integer), 1549912388825489413(Long), 小明6号(String), 6(Integer), 1549912388825489414(Long), 小明7号(String), 7(Integer), 1549912388825489415(Long), 小明8号(String), 8(Integer), 1549912388825489416(Long), 小明9号(String), 9(Integer), 1549912388825489417(Long), 小明10号(String), 10(Integer), 1549912388825489418(Long), 小明11号(String), 11(Integer), 1549912388825489419(Long), 小明12号(String), 12(Integer), 1549912388825489420(Long), 小明13号(String), 13(Integer), 1549912388825489421(Long), 小明14号(String), 14(Integer), 1549912388825489422(Long), 小明15号(String), 15(Integer), 1549912388825489423(Long), 小明16号(String), 16(Integer), 1549912388825489424(Long), 小明17号(String), 17(Integer), 1549912388825489425(Long), 小明18号(String), 18(Integer), 1549912388825489426(Long), 小明19号(String), 19(Integer)
     *
     * select * from student where id = 1549912388737409026
     * Student(id=1549912388737409026, name=小明0号, age=0)
     */
    @Test
    public void test1() {
        log.error("--------------------------------------insert-------------------------------------------------------");
        List<Long> ids = Lists.newArrayList();
        for (int i = 0; i < 2; i++) {
            Student student = new Student("小明" + i + "号", i);
            studentMapper.insert(student);
            ids.add(student.getId());
        }
        log.error("--------------------------------------insertBatchSomeColumn-------------------------------------------------------");
        List<Student> ss = Lists.newArrayList();
        for (int i = 2; i < 20; i++) {
            Student student = new Student("小明" + i + "号", i);
            ss.add(student);
        }
        studentMapper.insertBatchSomeColumn(ss);
        ids.addAll(ss.stream().map(Student::getId).collect(Collectors.toList()));

        Student select = studentMapper.select("select * from student where id = " + ids.get(0));
        System.out.println(select);
    }

    /**
     * 清空表中数据
     * delete from STUDENT
     */
    @Test
    public void test2() {
        log.error("--------------------------------------deleteAll-------------------------------------------------------");
        studentMapper.deleteAll();
    }

}