mybatis plus内置了好多CRUD,其中 EntityWrapper这个类就是。
这个类是mybatis plus帮我们写好的好多接口,就如同我们在dao层写好方法在xml中实现一样。
那么这个友好的类给我们实现了哪些方法呐,今天我们来通过看看源码,来具体说说,
/**
* Copyright (c) 2011-2014, hubin (jobob@qq.com).
* <p>
* Licensed under the Apache License, Version 2.0 (the "License"); you may not
* use this file except in compliance with the License. You may obtain a copy of
* the License at
* <p>
* http://www.apache.org/licenses/LICENSE-2.0
* <p>
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations under
* the License.
*/
package com.baomidou.mybatisplus.mapper;
import java.io.Serializable;
import java.util.Arrays;
import java.util.Collection;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import java.util.concurrent.atomic.AtomicInteger;
import com.baomidou.mybatisplus.enums.SqlLike;
import com.baomidou.mybatisplus.exceptions.MybatisPlusException;
import com.baomidou.mybatisplus.toolkit.ArrayUtils;
import com.baomidou.mybatisplus.toolkit.CollectionUtils;
import com.baomidou.mybatisplus.toolkit.MapUtils;
import com.baomidou.mybatisplus.toolkit.SqlUtils;
import com.baomidou.mybatisplus.toolkit.StringUtils;
/**
* <p>
* 条件构造抽象类,定义T-SQL语法
* </p>
*
* @author hubin , yanghu , Dyang , Caratacus
* @Date 2016-11-7
*/
@SuppressWarnings("serial")
public abstract class Wrapper<T> implements Serializable {
/**
* 占位符
*/
private static final String PLACE_HOLDER = "{%s}";
private static final String MYBATIS_PLUS_TOKEN = "#{%s.paramNameValuePairs.%s}";
private static final String MP_GENERAL_PARAMNAME = "MPGENVAL";
private static final String DEFAULT_PARAM_ALIAS = "ew";
protected String paramAlias = null;
/**
* SQL 查询字段内容,例如:id,name,age
*/
protected String sqlSelect = null;
/**
* 实现了TSQL语法的SQL实体
*/
protected SqlPlus sql = new SqlPlus();
/**
* 自定义是否输出sql为 WHERE OR AND OR OR
*/
protected Boolean isWhere;
/**
* 拼接WHERE后应该是AND还是OR
*/
protected String AND_OR = "AND";
private Map<String, Object> paramNameValuePairs = new HashMap<>(4);
private AtomicInteger paramNameSeq = new AtomicInteger(0);
/**
* 兼容EntityWrapper
*
* @return
*/
public T getEntity() {
return null;
}
public String getSqlSelect() {
if (StringUtils.isEmpty(sqlSelect)) {
return null;
}
return stripSqlInjection(sqlSelect);
}
public Wrapper<T> setSqlSelect(String sqlSelect) {
if (StringUtils.isNotEmpty(sqlSelect)) {
this.sqlSelect = sqlSelect;
}
return this;
}
/**
* SQL 片段 (子类实现)
*/
public abstract String getSqlSegment();
public String toString() {
String sqlSegment = getSqlSegment();
if (StringUtils.isNotEmpty(sqlSegment)) {
sqlSegment = sqlSegment.replaceAll("#\\{" + getParamAlias() + ".paramNameValuePairs.MPGENVAL[0-9]+}", "\\?");
}
return sqlSegment;
}
/**
* <p>
* SQL中WHERE关键字跟的条件语句
* </p>
* <p>
* eg: ew.where("name='zhangsan'").where("id={0}","123");
* <p>
* 输出: WHERE (NAME='zhangsan' AND id=123)
* </p>
*
* @param sqlWhere where语句
* @param params 参数集
* @return this
*/
public Wrapper<T> where(String sqlWhere, Object... params) {
sql.WHERE(formatSql(sqlWhere, params));
return this;
}
/**
* <p>
* 等同于SQL的"field=value"表达式
* </p>
*
* @param column
* @param params
* @return
*/
public Wrapper<T> eq(String column, Object params) {
sql.WHERE(formatSql(String.format("%s = {0}", column), params));
return this;
}
/**
* <p>
* 等同于SQL的"field <> value"表达式
* </p>
*
* @param column
* @param params
* @return
*/
public Wrapper<T> ne(String column, Object params) {
sql.WHERE(formatSql(String.format("%s <> {0}", column), params));
return this;
}
/**
* <p>
* 等同于SQL的"field=value"表达式
* </p>
*
* @param params
* @return
*/
@SuppressWarnings({"rawtypes", "unchecked"})
public Wrapper<T> allEq(Map<String, Object> params) {
if (MapUtils.isNotEmpty(params)) {
Iterator iterator = params.entrySet().iterator();
while (iterator.hasNext()) {
Map.Entry<String, Object> entry = (Map.Entry<String, Object>) iterator.next();
Object value = entry.getValue();
if (StringUtils.checkValNotNull(value)) {
sql.WHERE(formatSql(String.format("%s = {0}", entry.getKey()), entry.getValue()));
}
}
}
return this;
}
/**
* <p>
* 等同于SQL的"field>value"表达式
* </p>
*
* @param column
* @param params
* @return
*/
public Wrapper<T> gt(String column, Object params) {
sql.WHERE(formatSql(String.format("%s > {0}", column), params));
return this;
}
/**
* <p>
* 等同于SQL的"field>=value"表达式
* </p>
*
* @param column
* @param params
* @return
*/
public Wrapper<T> ge(String column, Object params) {
sql.WHERE(formatSql(String.format("%s >= {0}", column), params));
return this;
}
/**
* <p>
* 等同于SQL的"field<value"表达式
* </p>
*
* @param column
* @param params
* @return
*/
public Wrapper<T> lt(String column, Object params) {
sql.WHERE(formatSql(String.format("%s < {0}", column), params));
return this;
}
/**
* <p>
* 等同于SQL的"field<=value"表达式
* </p>
*
* @param column
* @param params
* @return
*/
public Wrapper<T> le(String column, Object params) {
sql.WHERE(formatSql(String.format("%s <= {0}", column), params));
return this;
}
/**
* <p>
* AND 连接后续条件
* </p>
*
* @param sqlAnd and条件语句
* @param params 参数集
* @return this
*/
public Wrapper<T> and(String sqlAnd, Object... params) {
sql.AND().WHERE(formatSql(sqlAnd, params));
return this;
}
/**
* <p>
* 使用AND连接并换行
* </p>
* <p>
* eg: ew.where("name='zhangsan'").and("id=11").andNew("statu=1"); 输出: WHERE
* (name='zhangsan' AND id=11) AND (statu=1)
* </p>
*
* @param sqlAnd AND 条件语句
* @param params 参数值
* @return this
*/
public Wrapper<T> andNew(String sqlAnd, Object... params) {
sql.AND_NEW().WHERE(formatSql(sqlAnd, params));
return this;
}
/**
* <p>
* 使用AND连接并换行
* </p>
* <p>
*
* @return this
*/
public Wrapper<T> and() {
sql.AND_NEW();
return this;
}
/**
* <p>
* 使用OR连接并换行
* </p>
*
* @return this
*/
public Wrapper<T> or() {
sql.OR_NEW();
return this;
}
/**
* <p>
* 添加OR条件
* </p>
*
* @param sqlOr or 条件语句
* @param params 参数集
* @return this
*/
public Wrapper<T> or(String sqlOr, Object... params) {
if (StringUtils.isEmpty(sql.toString())) {
AND_OR = "OR";
}
sql.OR().WHERE(formatSql(sqlOr, params));
return this;
}
/**
* <p>
* 使用OR换行,并添加一个带()的新的条件
* </p>
* <p>
* eg: ew.where("name='zhangsan'").and("id=11").orNew("statu=1"); 输出: WHERE
* (name='zhangsan' AND id=11) OR (statu=1)
* </p>
*
* @param sqlOr AND 条件语句
* @param params 参数值
* @return this
*/
public Wrapper<T> orNew(String sqlOr, Object... params) {
if (StringUtils.isEmpty(sql.toString())) {
AND_OR = "OR";
}
sql.OR_NEW().WHERE(formatSql(sqlOr, params));
return this;
}
/**
* <p>
* SQL中groupBy关键字跟的条件语句
* </p>
* <p>
* eg: ew.where("name='zhangsan'").groupBy("id,name")
* </p>
*
* @param columns SQL 中的 Group by 语句,无需输入 Group By 关键字
* @return this
*/
public Wrapper<T> groupBy(String columns) {
sql.GROUP_BY(columns);
return this;
}
/**
* <p>
* SQL中having关键字跟的条件语句
* </p>
* <p>
* eg: ew.groupBy("id,name").having("id={0}",22).and("password is not null")
* </p>
*
* @param sqlHaving having关键字后面跟随的语句
* @param params 参数集
* @return EntityWrapper<T>
*/
public Wrapper<T> having(String sqlHaving, Object... params) {
sql.HAVING(formatSql(sqlHaving, params));
return this;
}
/**
* <p>
* SQL中orderby关键字跟的条件语句
* </p>
* <p>
* eg: ew.groupBy("id,name").having("id={0}",22).and("password is not null"
* ).orderBy("id,name")
* </p>
*
* @param columns SQL 中的 order by 语句,无需输入 Order By 关键字
* @return this
*/
public Wrapper<T> orderBy(String columns) {
sql.ORDER_BY(columns);
return this;
}
/**
* <p>
* SQL中orderby关键字跟的条件语句,可根据变更动态排序
* </p>
*
* @param columns SQL 中的 order by 语句,无需输入 Order By 关键字
* @param isAsc 是否为升序
* @return this
*/
public Wrapper<T> orderBy(String columns, boolean isAsc) {
if (StringUtils.isNotEmpty(columns)) {
sql.ORDER_BY(columns + (isAsc ? " ASC" : " DESC"));
}
return this;
}
/**
* LIKE条件语句,value中无需前后%
*
* @param column 字段名称
* @param value 匹配值
* @return this
*/
public Wrapper<T> like(String column, String value) {
handerLike(column, value, SqlLike.DEFAULT, false);
return this;
}
/**
* NOT LIKE条件语句,value中无需前后%
*
* @param column 字段名称
* @param value 匹配值
* @return this
*/
public Wrapper<T> notLike(String column, String value) {
handerLike(column, value, SqlLike.DEFAULT, true);
return this;
}
/**
* 处理LIKE操作
*
* @param column 字段名称
* @param value like匹配值
* @param isNot 是否为NOT LIKE操作
*/
private void handerLike(String column, String value, SqlLike type, boolean isNot) {
if (StringUtils.isNotEmpty(column) && StringUtils.isNotEmpty(value)) {
StringBuilder inSql = new StringBuilder();
inSql.append(column);
if (isNot) {
inSql.append(" NOT");
}
inSql.append(" LIKE {0}");
sql.WHERE(formatSql(inSql.toString(), SqlUtils.concatLike(value, type)));
}
}
/**
* LIKE条件语句,value中无需前后%
*
* @param column 字段名称
* @param value 匹配值
* @param type
* @return this
*/
public Wrapper<T> like(String column, String value, SqlLike type) {
handerLike(column, value, type, false);
return this;
}
/**
* NOT LIKE条件语句,value中无需前后%
*
* @param column 字段名称
* @param value 匹配值
* @param type
* @return this
*/
public Wrapper<T> notLike(String column, String value, SqlLike type) {
handerLike(column, value, type, true);
return this;
}
/**
* is not null 条件
*
* @param columns 字段名称。多个字段以逗号分隔。
* @return this
*/
public Wrapper<T> isNotNull(String columns) {
sql.IS_NOT_NULL(columns);
return this;
}
/**
* is not null 条件
*
* @param columns 字段名称。多个字段以逗号分隔。
* @return this
*/
public Wrapper<T> isNull(String columns) {
sql.IS_NULL(columns);
return this;
}
/**
* EXISTS 条件语句,目前适配mysql及oracle
*
* @param value 匹配值
* @return this
*/
public Wrapper<T> exists(String value) {
sql.EXISTS(value);
return this;
}
/**
* NOT EXISTS条件语句
*
* @param value 匹配值
* @return this
*/
public Wrapper<T> notExists(String value) {
sql.NOT_EXISTS(value);
return this;
}
/**
* IN 条件语句,目前适配mysql及oracle
*
* @param column 字段名称
* @param value 逗号拼接的字符串
* @return this
*/
public Wrapper<T> in(String column, String value) {
if (StringUtils.isNotEmpty(value)) {
in(column, StringUtils.splitWorker(value, ",", -1, false));
}
return this;
}
/**
* NOT IN条件语句
*
* @param column 字段名称
* @param value 逗号拼接的字符串
* @return this
*/
public Wrapper<T> notIn(String column, String value) {
if (StringUtils.isNotEmpty(value)) {
notIn(column, StringUtils.splitWorker(value, ",", -1, false));
}
return this;
}
/**
* IN 条件语句,目前适配mysql及oracle
*
* @param column 字段名称
* @param value 匹配值 List集合
* @return this
*/
public Wrapper<T> in(String column, Collection<?> value) {
if (CollectionUtils.isNotEmpty(value))
sql.WHERE(formatSql(inExpression(column, value, false), value.toArray()));
return this;
}
/**
* NOT IN 条件语句,目前适配mysql及oracle
*
* @param column 字段名称
* @param value 匹配值 List集合
* @return this
*/
public Wrapper<T> notIn(String column, Collection<?> value) {
if (CollectionUtils.isNotEmpty(value))
sql.WHERE(formatSql(inExpression(column, value, true), value.toArray()));
return this;
}
/**
* IN 条件语句,目前适配mysql及oracle
*
* @param column 字段名称
* @param value 匹配值 object数组
* @return this
*/
public Wrapper<T> in(String column, Object[] value) {
if (ArrayUtils.isNotEmpty(value))
sql.WHERE(formatSql(inExpression(column, Arrays.asList(value), false), value));
return this;
}
/**
* NOT IN 条件语句,目前适配mysql及oracle
*
* @param column 字段名称
* @param value 匹配值 object数组
* @return this
*/
public Wrapper<T> notIn(String column, Object... value) {
if (ArrayUtils.isNotEmpty(value))
sql.WHERE(formatSql(inExpression(column, Arrays.asList(value), true), value));
return this;
}
/**
* 获取in表达式
*
* @param column 字段名称
* @param value 集合List
* @param isNot 是否为NOT IN操作
*/
private String inExpression(String column, Collection<?> value, boolean isNot) {
if (StringUtils.isNotEmpty(column) && CollectionUtils.isNotEmpty(value)) {
StringBuilder inSql = new StringBuilder();
inSql.append(column);
if (isNot) {
inSql.append(" NOT");
}
inSql.append(" IN ");
inSql.append("(");
int size = value.size();
for (int i = 0; i < size; i++) {
inSql.append(String.format(PLACE_HOLDER, i));
if (i + 1 < size) {
inSql.append(",");
}
}
inSql.append(")");
return inSql.toString();
}
return null;
}
/**
* betwwee 条件语句
*
* @param column 字段名称
* @param val1
* @param val2
* @return this
*/
public Wrapper<T> between(String column, Object val1, Object val2) {
sql.WHERE(formatSql(String.format("%s BETWEEN {0} AND {1}", column), val1, val2));
return this;
}
/**
* NOT betwwee 条件语句
*
* @param column 字段名称
* @param val1
* @param val2
* @return this
*/
public Wrapper<T> notBetween(String column, Object val1, Object val2) {
sql.WHERE(formatSql(String.format("%s NOT BETWEEN {0} AND {1}", column), val1, val2));
return this;
}
/**
* 为了兼容之前的版本,可使用where()或and()替代
*
* @param sqlWhere where sql部分
* @param params 参数集
* @return this
*/
public Wrapper<T> addFilter(String sqlWhere, Object... params) {
return and(sqlWhere, params);
}
/**
* <p>
* 根据判断条件来添加条件语句部分 使用 andIf() 替代
* </p>
* <p>
* eg: ew.filterIfNeed(false,"name='zhangsan'").where("name='zhangsan'")
* .filterIfNeed(true,"id={0}",22)
* <p>
* 输出: WHERE (name='zhangsan' AND id=22)
* </p>
*
* @param need 是否需要添加该条件
* @param sqlWhere 条件语句
* @param params 参数集
* @return this
*/
public Wrapper<T> addFilterIfNeed(boolean need, String sqlWhere, Object... params) {
return need ? where(sqlWhere, params) : this;
}
/**
* <p>
* SQL注入内容剥离
* </p>
*
* @param value 待处理内容
* @return this
*/
protected String stripSqlInjection(String value) {
return value.replaceAll("('.+--)|(--)|(\\|)|(%7C)", "");
}
/**
* <p>
* 格式化SQL
* </p>
*
* @param sqlStr SQL语句部分
* @param params 参数集
* @return this
*/
protected String formatSql(String sqlStr, Object... params) {
return formatSqlIfNeed(true, sqlStr, params);
}
/**
* <p>
* 根据需要格式化SQL<BR>
* <BR>
* Format SQL for methods: EntityWrapper.where/and/or...("name={0}", value);
* ALL the {<b>i</b>} will be replaced with #{MPGENVAL<b>i</b>}<BR>
* <BR>
* ew.where("sample_name=<b>{0}</b>", "haha").and("sample_age ><b>{0}</b>
* and sample_age<<b>{1}</b>", 18, 30) <b>TO</b>
* sample_name=<b>#{MPGENVAL1}</b> and sample_age>#<b>{MPGENVAL2}</b> and
* sample_age<<b>#{MPGENVAL3}</b><BR>
* </p>
*
* @param need 是否需要格式化
* @param sqlStr SQL语句部分
* @param params 参数集
* @return this
*/
protected String formatSqlIfNeed(boolean need, String sqlStr, Object... params) {
if (!need || StringUtils.isEmpty(sqlStr)) {
return null;
}
// #200
if (ArrayUtils.isNotEmpty(params)) {
for (int i = 0; i < params.length; ++i) {
String genParamName = MP_GENERAL_PARAMNAME + paramNameSeq.incrementAndGet();
sqlStr = sqlStr.replace(String.format(PLACE_HOLDER, i),
String.format(MYBATIS_PLUS_TOKEN, getParamAlias(), genParamName));
paramNameValuePairs.put(genParamName, params[i]);
}
}
return sqlStr;
}
/**
* <p>
* 自定义是否输出sql开头为 `WHERE` OR `AND` OR `OR`
* </p>
*
* @param bool
* @return this
*/
public Wrapper<T> isWhere(Boolean bool) {
this.isWhere = bool;
return this;
}
/**
* <p>
* SQL LIMIT
* </p>
*
* @param begin 起始
* @param end 结束
* @return this
*/
public Wrapper<T> limit(int begin, int end) {
sql.LIMIT(begin, end);
return this;
}
/**
* Fix issue 200.
*
* @return
* @since 2.0.3
*/
public Map<String, Object> getParamNameValuePairs() {
return paramNameValuePairs;
}
public String getParamAlias() {
return StringUtils.isEmpty(paramAlias) ? DEFAULT_PARAM_ALIAS : paramAlias;
}
/**
* <p>
* 调用该方法时 应当在吃初始化时优先设置该值 不要重复设置该值 要不然我就给你抛异常了
* </p>
*
* @param paramAlias
* @return
*/
public Wrapper<T> setParamAlias(String paramAlias) {
if (StringUtils.isNotEmpty(getSqlSegment())) {
throw new MybatisPlusException("Error: Please call this method when initializing!");
}
if (StringUtils.isNotEmpty(this.paramAlias)) {
throw new MybatisPlusException("Error: Please do not call the method repeatedly!");
}
this.paramAlias = paramAlias;
return this;
}
}
最后说一句,阅读源码,你会收获很多,看到别人的处理方式,你会有很大进步的。哈哈,今天你学到了吗