[英]How to force Mybatis to do a case sensitive select using dynamic criteria
我正在為 Mybatis DB 映射器構建動態查詢,以訪問 MySql 數據庫。 查詢由包含選擇字段的 XML 配置文件驅動。 所以我動態創建了一個 critera 對象。 我的問題是,如果選擇字段之一是字符串,則選擇返回不需要的記錄,因為它不區分大小寫
例如,如果選擇值為“Analog1”,這將匹配值為“analog1”的記錄。
問題是,我可以強制底層 SELECT 區分大小寫嗎? 我知道
select * from Label where binary Label_Name = 'analog1';
只會匹配 'analog1' 而不是 'Analog1'。 但是如何告訴 Mybatis 查詢在查詢中使用二進制限定符呢?
這是我創建條件的代碼。 如您所見,這一切都是使用反射動態完成的,沒有任何硬編碼:
private Object findMatchingRecord(TLVMessageHandlerData data, Object databaseMapperObject, Object domainObject, ActiveRecordDataType activeRecordData)
throws TLVMessageHandlerException {
if (activeRecordData == null) {
return false;
}
String domainClassName = domainObject.getClass().getName();
try {
String exampleClassName = domainClassName + "Example";
Class<?> exampleClass = Class.forName(exampleClassName);
Object exampleObject = exampleClass.newInstance();
Method createCriteriaMethod = exampleClass.getDeclaredMethod("createCriteria", (Class<?>[])null);
Object criteriaObject = createCriteriaMethod.invoke(exampleObject, (Object[])null);
for (String selectField : activeRecordData.getSelectField()) {
String criteriaMethodName = "and" + firstCharToUpper(selectField) + "EqualTo";
Class<?> selectFieldType = domainObject.getClass().getDeclaredField(selectField).getType();
Method criteriaMethod = criteriaObject.getClass().getMethod(criteriaMethodName, selectFieldType);
Method getSelectFieldMethod = domainObject.getClass().getDeclaredMethod("get" + firstCharToUpper(selectField));
Object selectFieldValue = getSelectFieldMethod.invoke(domainObject, (Object[])null);
if (selectFieldValue != null) {
criteriaMethod.invoke(criteriaObject, new Object[] { selectFieldValue });
}
}
List<?> resultSet = tlvMessageProcessingDelegate.selectByExample(databaseMapperObject, exampleObject);
if (resultSet.size() > 0) {
return resultSet.get(0);
}
else {
return null;
}
}
catch(..... Various exceptions.....) {
}
有一種方法可以通過修改用於創建查詢條件的“示例”類來做到這一點。 假設您有一個名為Label
的 Mybatis 域對象。 這將有一個關聯的LabelExample
。 請注意,我已將“二進制”限定符添加到生成的標准方法中。 這似乎為我完成了這項工作,並導致區分大小寫的查詢。
public class LabelExample {
...
/**
* This class was generated by MyBatis Generator. This class corresponds to the database table Label
* @mbggenerated
*/
protected abstract static class GeneratedCriteria {
public Criteria andLabelNameEqualTo(String value) {
addCriterion("binary Label_Name =", value, "labelName");
return (Criteria) this;
}
...
}
我相信這是可能的,但不能使用簡單的查詢樣式。
這在Mybatis Generator 文檔中定義為以下形式:
TestTableExample example = new TestTableExample();
example.createCriteria().andField1EqualTo("abc");
這會導致這樣的查詢過濾器:
where field1 = 'abc'
相反,我認為您需要使用復雜的查詢表單並將其與插件結合以啟用ILIKE -esque 搜索。
有一個這樣的插件示例,它隨mybatis-generator 一起提供。 為了完整起見,我重現了下面的代碼:
/*
* Copyright 2009 The Apache Software Foundation
*
* 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
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* 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 org.mybatis.generator.plugins;
import java.util.List;
import org.mybatis.generator.api.PluginAdapter;
import org.mybatis.generator.api.IntrospectedColumn;
import org.mybatis.generator.api.IntrospectedTable;
import org.mybatis.generator.api.dom.java.FullyQualifiedJavaType;
import org.mybatis.generator.api.dom.java.InnerClass;
import org.mybatis.generator.api.dom.java.JavaVisibility;
import org.mybatis.generator.api.dom.java.Method;
import org.mybatis.generator.api.dom.java.Parameter;
import org.mybatis.generator.api.dom.java.TopLevelClass;
import org.mybatis.generator.codegen.ibatis2.Ibatis2FormattingUtilities;
/**
* This plugin demonstrates adding methods to the example class to enable
* case-insensitive LIKE searches. It shows hows to construct new methods and
* add them to an existing class.
*
* This plugin only adds methods for String fields mapped to a JDBC character
* type (CHAR, VARCHAR, etc.)
*
* @author Jeff Butler
*
*/
public class CaseInsensitiveLikePlugin extends PluginAdapter {
/**
*
*/
public CaseInsensitiveLikePlugin() {
super();
}
public boolean validate(List<String> warnings) {
return true;
}
@Override
public boolean modelExampleClassGenerated(TopLevelClass topLevelClass,
IntrospectedTable introspectedTable) {
InnerClass criteria = null;
// first, find the Criteria inner class
for (InnerClass innerClass : topLevelClass.getInnerClasses()) {
if ("GeneratedCriteria".equals(innerClass.getType().getShortName())) { //$NON-NLS-1$
criteria = innerClass;
break;
}
}
if (criteria == null) {
// can't find the inner class for some reason, bail out.
return true;
}
for (IntrospectedColumn introspectedColumn : introspectedTable
.getNonBLOBColumns()) {
if (!introspectedColumn.isJdbcCharacterColumn()
|| !introspectedColumn.isStringColumn()) {
continue;
}
Method method = new Method();
method.setVisibility(JavaVisibility.PUBLIC);
method.addParameter(new Parameter(introspectedColumn
.getFullyQualifiedJavaType(), "value")); //$NON-NLS-1$
StringBuilder sb = new StringBuilder();
sb.append(introspectedColumn.getJavaProperty());
sb.setCharAt(0, Character.toUpperCase(sb.charAt(0)));
sb.insert(0, "and"); //$NON-NLS-1$
sb.append("LikeInsensitive"); //$NON-NLS-1$
method.setName(sb.toString());
method.setReturnType(FullyQualifiedJavaType.getCriteriaInstance());
sb.setLength(0);
sb.append("addCriterion(\"upper("); //$NON-NLS-1$
sb.append(Ibatis2FormattingUtilities
.getAliasedActualColumnName(introspectedColumn));
sb.append(") like\", value.toUpperCase(), \""); //$NON-NLS-1$
sb.append(introspectedColumn.getJavaProperty());
sb.append("\");"); //$NON-NLS-1$
method.addBodyLine(sb.toString());
method.addBodyLine("return (Criteria) this;"); //$NON-NLS-1$
criteria.addMethod(method);
}
return true;
}
}
實現起來似乎有點痛苦,不幸的是,高級Mybatis功能似乎經常出現這種情況,唯一的文檔實際上是檢入git repo 的示例。
您可能想看看使用內置於Mybatis的SQL Builder類,您可以在其中使用WHERE
方法並在參數中指定ILIKE
,盡管我知道考慮到生成器代碼的當前使用情況,這可能是一個橋梁。
有一個 mybatis 生成器插件org.mybatis.generator.plugins.CaseInsensitiveLikePlugin
該插件向 Example 類(實際上是 Criteria 內部類)添加方法以支持不區分大小寫的 LIKE 搜索
您可以使用不敏感的“XXXX”,它可以與任何數據庫一起使用
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