MybatisGenerator外掛開發六【邏輯刪除】

摘要： 邏輯刪除在專案中也是很常見的，比較常見的方式是新增一個deleted 的標記位，當然也有其他的實現方式。本章節的外掛針對的是新增標記位的方式來實現邏輯刪除的。如果說沒有和deleted 標記位一起的唯一聯合索引，那是很容易實現的，標誌位只要兩個值：0、1，然後通過up...

邏輯刪除在專案中也是很常見的，比較常見的方式是新增一個deleted 的標記位，當然也有其他的實現方式。本章節的外掛針對的是新增標記位的方式來實現邏輯刪除的。如果說沒有和deleted 標記位一起的唯一聯合索引，那是很容易實現的，標誌位只要兩個值：0、1，然後通過updateByExampleSelective 修改就可以了。但是往往我們表中會有唯一索引在，比如說名字不能重複之類的。這個時候我們採取的簡單的處理方式是set deleted = deleted + 1 來避免刪除後不能再次新增同樣資料的問題。索性這個外掛就提供了兩個方法：logicDelete 和logicDeleteWithUIndex 。

修改Mapper介面和SqlMap檔案

public class LogicDeletePluginextends PluginAdapter{

@Override
public boolean validate(List<String> list){
return true;
}

/**
* 修改Mapper類
*/
@Override
public boolean clientGenerated(Interface interfaze, TopLevelClass topLevelClass, IntrospectedTable introspectedTable){
addLogicDeleteMethod(interfaze);
return true;
}

private void addLogicDeleteMethod(Interface interfaze){
// 方法的返回值
FullyQualifiedJavaType returnTypeInt = FullyQualifiedJavaType.getIntInstance();

Method logicDeleteMethod = new Method();
// 1.設定方法可見性
logicDeleteMethod.setVisibility(JavaVisibility.PUBLIC);
// 2.設定返回值型別 int型別
logicDeleteMethod.setReturnType(returnTypeInt);
// 3.設定方法名
logicDeleteMethod.setName("logicDelete");
// 4.設定引數列表
FullyQualifiedJavaType paramType = PrimitiveTypeWrapper.getLongInstance();
logicDeleteMethod.addParameter(new Parameter(paramType, "id"));
interfaze.addMethod(logicDeleteMethod);

Method logicDeleteWithUIndexMethod = new Method();
// 1.設定方法可見性
logicDeleteWithUIndexMethod.setVisibility(JavaVisibility.PUBLIC);
// 2.設定返回值型別 int型別
logicDeleteWithUIndexMethod.setReturnType(returnTypeInt);
// 3.設定方法名
logicDeleteWithUIndexMethod.setName("logicDeleteWithUIndex");
// 4.設定引數列表
FullyQualifiedJavaType paramTypeSelective = PrimitiveTypeWrapper.getLongInstance();
logicDeleteWithUIndexMethod.addParameter(new Parameter(paramTypeSelective, "id", "@Param(\"id\")"));
logicDeleteWithUIndexMethod.addParameter(new Parameter(FullyQualifiedJavaType.getStringInstance(), "uIndexes", "@Param(\"uIndexes\")", true));
interfaze.addMethod(logicDeleteWithUIndexMethod);
}


/**
* 修改Mapper.xml
*/
@Override
public boolean sqlMapDocumentGenerated(Document document, IntrospectedTable introspectedTable){
addLogicDeleteXml(document, introspectedTable);
addLogicDeleteWithUIndexXml(document, introspectedTable);
return true;
}

private void addLogicDeleteXml(Document document, IntrospectedTable introspectedTable){
XmlElement logicDeleteElement = new XmlElement("update");
logicDeleteElement.addAttribute(new Attribute("id", "logicDelete"));
logicDeleteElement.addAttribute(new Attribute("parameterType", "java.lang.Long"));

logicDeleteElement.addElement(new TextElement("update " + introspectedTable.getAliasedFullyQualifiedTableNameAtRuntime()));
logicDeleteElement.addElement(new TextElement("set deleted = 1, update_time = REPLACE(unix_timestamp(current_timestamp(3)),'.','') where id = #{id,jdbcType=BIGINT}"));

document.getRootElement().addElement(logicDeleteElement);
}

private void addLogicDeleteWithUIndexXml(Document document, IntrospectedTable introspectedTable){
XmlElement logicDeleteWithUIndexElement = new XmlElement("update");
logicDeleteWithUIndexElement.addAttribute(new Attribute("id", "logicDeleteWithUIndex"));
logicDeleteWithUIndexElement.addAttribute(new Attribute("parameterType", "map"));

logicDeleteWithUIndexElement.addElement(new TextElement("update " + introspectedTable.getAliasedFullyQualifiedTableNameAtRuntime() + " A,"));
logicDeleteWithUIndexElement.addElement(new TextElement("(select C.deleted from " + introspectedTable.getAliasedFullyQualifiedTableNameAtRuntime() + " C,"));
logicDeleteWithUIndexElement.addElement(new TextElement("(select"));

XmlElement foreachElement = new XmlElement("foreach");
foreachElement.addAttribute(new Attribute("collection", "uIndexes"));
foreachElement.addAttribute(new Attribute("index", "index"));
foreachElement.addAttribute(new Attribute("item", "column"));
foreachElement.addAttribute(new Attribute("separator", ","));
foreachElement.addElement(new TextElement("${column}"));
logicDeleteWithUIndexElement.addElement(foreachElement);

logicDeleteWithUIndexElement.addElement(new TextElement("from " + introspectedTable.getAliasedFullyQualifiedTableNameAtRuntime() + " where id = #{id,jdbcType=BIGINT}) D"));

XmlElement whereElement = new XmlElement("where");
XmlElement whereForachElement = new XmlElement("foreach");
whereForachElement.addAttribute(new Attribute("collection", "uIndexes"));
whereForachElement.addAttribute(new Attribute("index", "index"));
whereForachElement.addAttribute(new Attribute("item", "column"));
whereForachElement.addElement(new TextElement(" and C.${column} = D.${column}"));
whereElement.addElement(whereForachElement);
logicDeleteWithUIndexElement.addElement(whereElement);

logicDeleteWithUIndexElement.addElement(new TextElement("order by C.deleted desc limit 1) B"));
logicDeleteWithUIndexElement.addElement(new TextElement("set A.deleted = B.deleted + 1, A.update_time = REPLACE(unix_timestamp(current_timestamp(3)),'.','')"));
logicDeleteWithUIndexElement.addElement(new TextElement("where A.id = #{id,jdbcType=BIGINT}"));
logicDeleteWithUIndexElement.addElement(new TextElement("and A.deleted = 0"));

document.getRootElement().addElement(logicDeleteWithUIndexElement);
}
}

邏輯比較簡單，就是在Mapper介面和SqlMap檔案中新增方法和對應的sql語句就可以了。

檢視生成檔案

將外掛新增到專案中，並且執行完MybatisGenerator，我們來檢視下生成的相關檔案：

public interface AdministratorMapper{
...
int logicDelete(Long id);
int logicDeleteWithUIndex(@Param("id")Long id, @Param("uIndexes")String ... uIndexes);
}

<updateid="logicDelete"parameterType="java.lang.Long">
update administrator
set deleted = 1, update_time = REPLACE(unix_timestamp(current_timestamp(3)),'.','') where id = #{id,jdbcType=BIGINT}
 </update>

 <updateid="logicDeleteWithUIndex"parameterType="map">
update administrator A,
(select C.deletedfrom administrator C,
(select
<foreachcollection="uIndexes"index="index"item="column"separator=",">
${column}
</foreach>
from administrator where id = #{id,jdbcType=BIGINT}) D
<where>
<foreachcollection="uIndexes"index="index"item="column">
and C.${column} = D.${column}
</foreach>
</where>
order by C.deleted desc limit 1) B
set A.deleted = B.deleted + 1, A.update_time = REPLACE(unix_timestamp(current_timestamp(3)),'.','')
where A.id = #{id,jdbcType=BIGINT}
and A.deleted = 0
 </update>

如何使用

使用方式如下：

這裡同樣用到了之前新增到Model類中的表字段列舉。

administratorMapper.logicDeleteWithUIndex(id, Administrator.COLUMNS.MOBILE.getColumn()

本章節就到這裡了。以後要用外掛來實現一些特殊的Sql，應該可以舉一反三了。