Mybatis执行Update返回行数为负数

缺乏、安全感 2021-06-24 14:35 477阅读 0赞

获取mybatis的update行数，总是返回负数。后来在官网上找到原因，是由于defaultExecutorType的引起的，defaultExecutorType有三个执行器SIMPLE、REUSE和BATCH。其中BATCH可以批量更新操作缓存SQL以提高性能，但是有个缺陷就是无法获取update、delete返回的行数。defaultExecutorType的默认执行器是SIMPLE。

<table style="width:946px; border-collapse:collapse; border-spacing:0px; border:1px solid rgb(238,238,238); color:rgb(0,0,0); font-family:&quot;microsoft yahei&quot;; font-size:14px; line-height:26px"> 
 <thead style=""> 
  <tr style=""> 
   <th align="left" style="padding:8px; line-height:20px; vertical-align:top; border:1px solid rgb(238,238,238)"> 名称</th> 
   <th align="left" style="padding:8px; line-height:20px; vertical-align:top; border:1px solid rgb(238,238,238)"> 描述</th> 
  </tr> 
 </thead> 
 <tbody style=""> 
  <tr style=""> 
   <td align="left" style="padding:8px; line-height:20px; vertical-align:top; border:1px solid rgb(238,238,238)"> SIMPLE</td> 
   <td align="left" style="padding:8px; line-height:20px; vertical-align:top; border:1px solid rgb(238,238,238)"> 执行器执行其它语句</td> 
  </tr> 
  <tr style=""> 
   <td align="left" style="padding:8px; line-height:20px; vertical-align:top; border:1px solid rgb(238,238,238)"> REUSE</td> 
   <td align="left" style="padding:8px; line-height:20px; vertical-align:top; border:1px solid rgb(238,238,238)"> 可能重复使用prepared statements 语句</td> 
  </tr> 
  <tr style=""> 
   <td align="left" style="padding:8px; line-height:20px; vertical-align:top; border:1px solid rgb(238,238,238)"> BATCH</td> 
   <td align="left" style="padding:8px; line-height:20px; vertical-align:top; border:1px solid rgb(238,238,238)"> 可以重复执行语句和批量更新</td> 
  </tr> 
 </tbody> 
</table>

由于项目配置中启用了BATCH执行器，UPDATE和DELETE返回的行数就丢失了，把执行器改为SIMPLE即可。

通过查看源码可以发现，batch执行器返回的是最大批量执行条数：

public static final int BATCH_UPDATE_RETURN_VALUE = Integer.MIN_VALUE + 1002;
    
    public int doUpdate(MappedStatement ms, Object parameterObject) throws SQLException {
        final Configuration configuration = ms.getConfiguration();
        final StatementHandler handler = configuration.newStatementHandler(this, ms, parameterObject, RowBounds.DEFAULT, null, null);
        final BoundSql boundSql = handler.getBoundSql();
        final String sql = boundSql.getSql();
        final Statement stmt;
        if (sql.equals(currentSql) && ms.equals(currentStatement)) {
          int last = statementList.size() - 1;
          stmt = statementList.get(last);
          BatchResult batchResult = batchResultList.get(last);
          batchResult.addParameterObject(parameterObject);
        } else {
          Connection connection = getConnection(ms.getStatementLog());
          stmt = handler.prepare(connection);
          currentSql = sql;
          currentStatement = ms;
          statementList.add(stmt);
          batchResultList.add(new BatchResult(ms, sql, parameterObject));
        }
        handler.parameterize(stmt);
        handler.batch(stmt);
        return BATCH_UPDATE_RETURN_VALUE;
      }

<?xml version="1.0" encoding="UTF-8" ?> 
    <!DOCTYPE configuration PUBLIC "-//mybatis.org//DTD Config 3.0//EN" "http://mybatis.org/dtd/mybatis-3-config.dtd">
    <configuration>
        <settings>
            
            <setting name="cacheEnabled" value="true" />
            
            <setting name="lazyLoadingEnabled" value="true" />
            
            <setting name="aggressiveLazyLoading" value="false" />
            
            <setting name="multipleResultSetsEnabled" value="true" />
            
            <setting name="useColumnLabel" value="true" />
            
            <setting name="useGeneratedKeys" value="true" />
            
            <setting name="autoMappingBehavior" value="FULL" />
            
            
            
            
            <setting name="defaultStatementTimeout" value="25000" />
            
            
        </settings>
    
        
        <plugins>
            
            <plugin interceptor="com.rvho.mybatis.interceptor.MybatisPageInterceptor">
                <property name="databaseType" value="mysql"/>
            </plugin>
        </plugins>
    </configuration>