MybatisPlus QueryWrapper对象封装操作类
先把代码拿出来遛一遛
public class QueryWrapper<T> extends AbstractWrapper<T, String, QueryWrapper<T>> {
/**
* 查询字段
*/
private String sqlSelect;
public QueryWrapper() {
this(null);
}
public QueryWrapper(T entity) {
this.entity = entity;
this.initEntityClass();
this.initNeed();
}
public QueryWrapper(T entity, String... columns) {
this.entity = entity;
this.select(columns);
this.initEntityClass();
this.initNeed();
}
/**
* 非对外公开的构造方法,只用于生产嵌套 sql
*
* @param entityClass 本不应该需要的
*/
private QueryWrapper(T entity, Class<T> entityClass, AtomicInteger paramNameSeq,
Map<String, Object> paramNameValuePairs, MergeSegments mergeSegments) {
this.entity = entity;
this.entityClass = entityClass;
this.paramNameSeq = paramNameSeq;
this.paramNameValuePairs = paramNameValuePairs;
this.expression = mergeSegments;
}
public QueryWrapper<T> select(String... columns) {
if (ArrayUtils.isNotEmpty(columns)) {
this.sqlSelect = String.join(StringPool.COMMA, columns);
}
return typedThis;
}
public QueryWrapper<T> select(Predicate<TableFieldInfo> predicate) {
return select(entityClass, predicate);
}
/**
* <p>
* 过滤查询的字段信息(主键除外!)
* </p>
* <p>
* 例1: 只要 java 字段名以 "test" 开头的 -> select(i -> i.getProperty().startsWith("test"))
* 例2: 只要 java 字段属性是 CharSequence 类型的 -> select(TableFieldInfo::isCharSequence)
* 例3: 只要 java 字段没有填充策略的 -> select(i -> i.getFieldFill == FieldFill.DEFAULT)
* 例4: 要全部字段 -> select(i -> true)
* 例5: 只要主键字段 -> select(i -> false)
* </p>
*
* @param predicate 过滤方式
* @return this
*/
public QueryWrapper<T> select(Class<T> entityClass, Predicate<TableFieldInfo> predicate) {
this.entityClass = entityClass;
this.sqlSelect = TableInfoHelper.getTableInfo(getCheckEntityClass()).chooseSelect(predicate);
return typedThis;
}
/**
* <p>
* 返回一个支持 lambda 函数写法的 wrapper
* </p>
*/
public LambdaQueryWrapper<T> lambda() {
return new LambdaQueryWrapper<>(entity, entityClass, sqlSelect, paramNameSeq, paramNameValuePairs, expression);
}
@Override
public String getSqlSelect() {
return sqlSelect;
}
@Override
protected String columnToString(String column) {
return column;
}
/**
* <p>
* 用于生成嵌套 sql
* 故 sqlSelect 不向下传递
* </p>
*/
@Override
protected QueryWrapper<T> instance(AtomicInteger paramNameSeq, Map<String, Object> paramNameValuePairs) {
return new QueryWrapper<>(entity, entityClass, paramNameSeq, paramNameValuePairs, new MergeSegments());
}
}
public abstract class AbstractWrapper封装了很多类似下面的条件方法
@Override
public <V> This allEq(boolean condition, BiPredicate<R, V> filter, Map<R, V> params, boolean null2IsNull) {
if (condition && CollectionUtils.isNotEmpty(params)) {
params.forEach((k, v) -> {
if (filter.test(k, v)) {
if (StringUtils.checkValNotNull(v)) {
eq(k, v);
} else {
if (null2IsNull) {
isNull(k);
}
}
}
});
}
return typedThis;
}
@Override
public This eq(boolean condition, R column, Object val) {
return addCondition(condition, column, EQ, val);
}
@Override
public This ne(boolean condition, R column, Object val) {
return addCondition(condition, column, NE, val);
}
@Override
public This gt(boolean condition, R column, Object val) {
return addCondition(condition, column, GT, val);
}
@Override
public This ge(boolean condition, R column, Object val) {
return addCondition(condition, column, GE, val);
}
@Override
public This lt(boolean condition, R column, Object val) {
return addCondition(condition, column, LT, val);
}
@Override
public This le(boolean condition, R column, Object val) {
return addCondition(condition, column, LE, val);
}
@Override
public This like(boolean condition, R column, Object val) {
return doIt(condition, () -> columnToString(column), LIKE, () -> formatSql("{0}", StringPool.PERCENT + val + StringPool.PERCENT));
}
@Override
public This notLike(boolean condition, R column, Object val) {
return not(condition).like(condition, column, val);
}
@Override
public This likeLeft(boolean condition, R column, Object val) {
return doIt(condition, () -> columnToString(column), LIKE, () -> formatSql("{0}", StringPool.PERCENT + val));
}
@Override
public This likeRight(boolean condition, R column, Object val) {
return doIt(condition, () -> columnToString(column), LIKE, () -> formatSql("{0}", val + StringPool.PERCENT));
}
@Override
public This between(boolean condition, R column, Object val1, Object val2) {
return doIt(condition, () -> columnToString(column), BETWEEN, () -> formatSql("{0}", val1), AND,
() -> formatSql("{0}", val2));
}
@Override
public This notBetween(boolean condition, R column, Object val1, Object val2) {
return not(condition).between(condition, column, val1, val2);
}
@Override
public This and(boolean condition, Function<This, This> func) {
return and(condition).addNestedCondition(condition, func);
}
@Override
public This or(boolean condition, Function<This, This> func) {
return or(condition).addNestedCondition(condition, func);
}
@Override
public This nested(boolean condition, Function<This, This> func) {
return addNestedCondition(condition, func);
}
@Override
public This or(boolean condition) {
return doIt(condition, OR);
}
@Override
public This apply(boolean condition, String applySql, Object... value) {
return doIt(condition, APPLY, () -> formatSql(applySql, value));
}
@Override
public This last(boolean condition, String lastSql) {
if (condition) {
this.lastSql = StringPool.SPACE + lastSql;
}
return typedThis;
}
@Override
public This exists(boolean condition, String existsSql) {
return doIt(condition, EXISTS, () -> String.format("(%s)", existsSql));
}
@Override
public This notExists(boolean condition, String notExistsSql) {
return not(condition).exists(condition, notExistsSql);
}
@Override
public This isNull(boolean condition, R column) {
return doIt(condition, () -> columnToString(column), IS_NULL);
}
@Override
public This isNotNull(boolean condition, R column) {
return doIt(condition, () -> columnToString(column), IS_NOT_NULL);
}
@Override
public This in(boolean condition, R column, Collection<?> value) {
if (CollectionUtils.isEmpty(value)) {
return typedThis;
}
return doIt(condition, () -> columnToString(column), IN, inExpression(value));
}
来源：oschina
链接：https://my.oschina.net/u/4418711/blog/4793857