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Mybatis returns map data null field does not display query sql add each field judgment null IFNULL (rate,'') as rateResultType uses entity return

No need for map

SpringMVC+mybatis query data

When resultType= "map" is returned, if the data is an empty field, the field is omitted and not displayed. You can return null if the query data is empty by adding a configuration file.

Spring-mybatis.xml

If you want to configure the default value of rate, such as the "" string, you can set up a class that implements the TypeHandler interface of Mybatis

Public class EmptyStringIfNull implements TypeHandler {@ Override public String getResult (ResultSet rs, String columnName) throws SQLException {return (rs.getString (columnName) = = null)? ": rs.getString (columnName);} @ Override public String getResult (ResultSet rs, int columnIndex) throws SQLException {return (rs.getString (columnIndex) = null)?": rs.getString (columnIndex) @ Override public String getResult (CallableStatement cs, int columnIndex) throws SQLException {return (cs.getString (columnIndex) = = null)? "": cs.getString (columnIndex);} @ Override public void setParameter (PreparedStatement ps, int arg1, String str, JdbcType jdbcType) throws SQLException {}}

The definition and use in the sql.xml file are as follows

Mybatis returns map null field mybatis opens CallSettersOnNulls@Beanpublic SqlSessionFactory sqlSessionFactoryBean () throws Exception {SqlSessionFactoryBean sqlSessionFactoryBean = new SqlSessionFactoryBean (); sqlSessionFactoryBean.setDataSource (dataSource ()); Configuration configuration = new .configuration (); configuration.setCallSettersOnNulls (true); / / map returns empty field disappearance problem PageInterceptor pagePlugin = new PageInterceptor (); JalorResultSetInterceptor jalorResultSetPlugin = new JalorResultSetInterceptor (); ProgramInterceptor programPlugin = new ProgramInterceptor () / / add the plug-in sqlSessionFactoryBean.setPlugins (new Interceptor [] {pagePlugin, jalorResultSetPlugin, programPlugin}); sqlSessionFactoryBean.setConfiguration (configuration); return sqlSessionFactoryBean.getObject ();} above is all the content of the article "what to do if the null value field of map type data returned by mybatis is not displayed?" Thank you for reading! I believe we all have a certain understanding, hope to share the content to help you, if you want to learn more knowledge, welcome to follow the industry information channel!

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