JAVA general single table AND query operation, first record it, there will be time to improve later. Only support single table public AND query
1. Annotation
@Target({ElementType.METHOD, ElementType.FIELD, ElementType.ANNOTATION_TYPE, ElementType.CONSTRUCTOR, ElementType.PARAMETER})
@Retention(RetentionPolicy.RUNTIME)
@Documented
public @interface Condition {
/**
* 默认为 等于
*
* @return 等于
*/
ConditionEnum conditionEnum() default ConditionEnum.Equals;
/**
* 数据类型 默认 字符串
*
* @return 字符串
*/
DataTypeEnum dataTypeEnum() default DataTypeEnum.STRING;
/**
* DO的属性名，默认和属性值一致
*
* @return DO的属性名
*/
String fieldName() default "";
/**
* 格式
*
* @return 格式
*/
String format() default "";
}
2. General AND query class for basic query
@Slf4j
public class BaseForQuery<T> extends BaseMapper<T> {
/**
* DESC
*/
private final static String DESC = "desc";
/**
* 获取没有特殊操作的查询条件
*
* @param queryParams 查询的参数
* @param entityObj 实体对象
* @return 返回查询的对象
*/
protected static <K extends BaseQuery, V> Example getExample(final K queryParams, final Class<V> entityObj) {
final Example example = new Example(entityObj, false);
if (queryParams == null) {
return example;
}
// 数据库对象的字段
final Map<String, Annotation[]> hashMapDb = FieldUtil.getFieldsAnnotations(entityObj);
if (hashMapDb == null || CollectionUtils.isEmpty(hashMapDb.entrySet())) {
return example;
}
// 排序
if (!StringUtils.isEmpty(queryParams.getSort())) {
if (DESC.equalsIgnoreCase(queryParams.getDirection())) {
example.orderBy(queryParams.getSort()).desc();
} else {
example.orderBy(queryParams.getSort()).asc();
}
}
// 条件
BaseForQuery.getCondition(example, queryParams, hashMapDb);
return example;
}
/**
* 设置 条件
*
* @param example 条件
* @param queryParams 请求参数
* @param hashMapDb 数据库
*/
private static <K extends BaseQuery> void getCondition(final Example example, final K queryParams,
final Map<String, Annotation[]> hashMapDb) {
final Example.Criteria criteria = example.createCriteria();
BaseForQuery.getCondition(criteria, queryParams, hashMapDb);
}
/**
* 获取条件
*
* @param criteria 查询条件
* @param hashMapDb 数据库字段
*/
private static <K> void getCondition(final Example.Criteria criteria, final K queryParams
, final Map<String, Annotation[]> hashMapDb) {
final Field[] fields = queryParams.getClass().getDeclaredFields();
if (Object.class.equals(queryParams) || Object.class.equals(queryParams.getClass())) {
return;
}
Object superInstance = null;
try {
superInstance = queryParams.getClass().getSuperclass().newInstance();
} catch (final InstantiationException e) {
log.error("{}", e);
} catch (final IllegalAccessException e) {
log.error("{}", e);
}
BeanUtils.copyProperties(queryParams, superInstance);
if (fields == null || fields.length == 0) {
// 递归调用
BaseForQuery.getCondition(criteria, superInstance, hashMapDb);
return;
}
for (final Field field : fields) {
// 获取字段对应的值
Object value;
try {
field.setAccessible(true);
value = field.get(queryParams);
} catch (final IllegalAccessException e) {
continue;
}
if (StringUtils.isEmpty(value)) {
continue;
}
final Condition condition = field.getAnnotation(Condition.class);
if (condition == null) {
continue;
}
// 用数据库生成的字段名称，避免异常
String fieldName = condition.fieldName();
if (StringUtils.isEmpty(fieldName)) {
fieldName = field.getName();
}
final String finalFieldName = fieldName;
final Optional<String> optionalField = hashMapDb.keySet().stream()
.filter(n -> n.equalsIgnoreCase(finalFieldName)).findAny();
if (!optionalField.isPresent()) {
continue;
}
if (!StringUtils.isEmpty(condition.format()) && condition.dataTypeEnum().getKey() == Date.class) {
value = Date.from(LocalDateTime.parse(value.toString(), DateTimeFormatter
.ofPattern(condition.format())).atZone(ZoneId.systemDefault()).toInstant());
}
switch (condition.conditionEnum().getKey()) {
case "Equals":
criteria.andEqualTo(fieldName, value);
break;
case "Like":
criteria.andLike(fieldName, String.format("%s%", value));
break;
case "GreaterThan":
criteria.andGreaterThan(fieldName, value);
break;
case "GreaterThanOrEqualTo":
criteria.andGreaterThanOrEqualTo(fieldName, value);
break;
case "LessThan":
criteria.andLessThan(fieldName, value);
break;
case "LessThanOrEqualTo":
criteria.andLessThanOrEqualTo(fieldName, value);
break;
case "IsNotNull":
criteria.andIsNotNull(fieldName);
break;
case "IsNull":
criteria.andIsNull(fieldName);
break;
default:
break;
}
}
// 递归调用
BaseForQuery.getCondition(criteria, superInstance, hashMapDb);
}
/**
* 排序
*
* @param queryParams 请求参数
* @param example 查询条件
* @param hashMapDb 数据库的字段
* @param <K> 泛型
*/
private static <K extends BaseQuery> void setOrderBy(final K queryParams, final Example example, final Map<String, Annotation[]> hashMapDb) {
if (!StringUtils.isEmpty(queryParams.getSort())) {
String sort = queryParams.getSort();
final Optional<String> optionalField = hashMapDb.keySet().stream().filter(n ->
n.equalsIgnoreCase(queryParams.getSort())).findAny();
if (optionalField.isPresent()) {
// 获取属性对应的字段
sort = optionalField.get();
final Optional<Annotation> annotation = Arrays.stream(hashMapDb
.get(sort)).filter(n -> n instanceof Column).findAny();
if (annotation.isPresent()) {
final Column column = (Column) annotation.get();
sort = column.name();
}
}
if (StringUtils.isEmpty(queryParams.getDirection())) {
example.setOrderByClause(sort);
} else {
example.setOrderByClause(sort.concat(" ").concat(queryParams.getDirection()));
}
}
}
/**
* 获取总行数和查询的条件
*
* @param queryParams 查询的请求参数
* @param entityObj 实体对象
* @param <K> 查询的请求参数 泛型对象
* @param <V> 实体对象 泛型对象
* @return 返回总的行数
*/
protected <K extends BaseQuery, V> ResultInfo<List<T>, BaseSummary> getPagerData(final K queryParams, final Class<V> entityObj) {
final Example example = BaseForQuery.getExample(queryParams, entityObj);
return this.getPagerData(queryParams, example);
}
/**
* 获取总行数和查询的条件
*
* @param queryParams 查询的请求参数
* @param example 查询条件Example
* @param <K> 查询的请求参数 泛型对象
* @return 返回总的行数
*/
protected <K extends BaseQuery> ResultInfo<List<T>, BaseSummary> getPagerData(final K queryParams, final Example example) {
final ResultInfo resultInfo = new ResultInfo();
final int count = this.mapper.selectCountByExample(example);
final BaseSummary baseSummary = new BaseSummary();
baseSummary.setTotalRows(count);
// 总条数
resultInfo.setSummary(baseSummary);
List<T> list = new ArrayList<>();
if (baseSummary.getTotalRows() != 0) {
// 明细数据
final int pageNo = queryParams.getPageNo();
final int pageSize = queryParams.getPageSize();
final int offset = (pageNo - 1) * pageSize;
final RowBounds rowBounds = new RowBounds(offset, pageSize);
// 查询数据
list = super.mapper.selectByExampleAndRowBounds(example, rowBounds);
}
resultInfo.setDetail(list);
return resultInfo;
}
/**
* 返回分页之后的数据
*
* @param k 带有分页的信息
* @param lst 列表
* @param <K> 泛型
* @return 返回分页之后的数据
*/
protected static <K extends BaseQuery, V> List<V> getLists(final K k, final List<V> lst) {
final int beginIndex = (k.getPageNo() - 1) * k.getPageSize();
int endIndex = k.getPageNo() * k.getPageSize();
if (lst.size() < endIndex) {
endIndex = lst.size();
}
return lst.subList(beginIndex, endIndex);
}
/**
* 排序
*
* @param forQuery 查询条件
* @param example example
*/
protected <T extends BaseQuery> void setExampleOrderBy(final T forQuery, final Example example) {
if (!StringUtils.isEmpty(forQuery.getSort())) {
if (!StringUtils.isEmpty(forQuery.getDirection()) && DESC.equalsIgnoreCase(forQuery.getDirection())) {
example.orderBy(forQuery.getSort()).desc();
} else {
example.orderBy(forQuery.getSort()).asc();
}
}
}
}
3. BaseMapper class
import org.springframework.beans.factory.annotation.Autowired;
import tk.mybatis.mapper.common.Mapper;
public class BaseMapper<T> {
/**
* 基本信息
*/
@Autowired
protected Mapper<T> mapper;
}