[简单]mybatis判断数字类型

fairyguo

　　昨天同事反馈mybatis保存不了int类型的属性,一直报错，错误信息如下:

Caused by: java.lang.NumberFormatException: For input string: "null"
at sun.misc.FloatingDecimal.readJavaFormatString(Unknown Source)
at sun.misc.FloatingDecimal.parseDouble(Unknown Source)
at java.lang.Double.parseDouble(Unknown Source)
at org.apache.ibatis.ognl.OgnlOps.doubleValue(OgnlOps.java:259)
at org.apache.ibatis.ognl.OgnlOps.compareWithConversion(OgnlOps.java:144)
at org.apache.ibatis.ognl.OgnlOps.isEqual(OgnlOps.java:186)
at org.apache.ibatis.ognl.OgnlOps.equal(OgnlOps.java:578)
at org.apache.ibatis.ognl.ASTNotEq.getValueBody(ASTNotEq.java:51)
at org.apache.ibatis.ognl.SimpleNode.evaluateGetValueBody(SimpleNode.java:170)
at org.apache.ibatis.ognl.SimpleNode.getValue(SimpleNode.java:210)
at org.apache.ibatis.ognl.ASTAnd.getValueBody(ASTAnd.java:56)
at org.apache.ibatis.ognl.SimpleNode.evaluateGetValueBody(SimpleNode.java:170)
at org.apache.ibatis.ognl.SimpleNode.getValue(SimpleNode.java:210)
at org.apache.ibatis.ognl.Ognl.getValue(Ognl.java:333)
at org.apache.ibatis.ognl.Ognl.getValue(Ognl.java:413)
at org.apache.ibatis.ognl.Ognl.getValue(Ognl.java:395)
at org.apache.ibatis.builder.xml.dynamic.OgnlCache.getValue(OgnlCache.java:42)
at org.apache.ibatis.builder.xml.dynamic.ExpressionEvaluator.evaluateBoolean(ExpressionEvaluator.java:32)
at org.apache.ibatis.builder.xml.dynamic.IfSqlNode.apply(IfSqlNode.java:30)
at org.apache.ibatis.builder.xml.dynamic.MixedSqlNode.apply(MixedSqlNode.java:29)
at org.apache.ibatis.builder.xml.dynamic.TrimSqlNode.apply(TrimSqlNode.java:42)
at org.apache.ibatis.builder.xml.dynamic.MixedSqlNode.apply(MixedSqlNode.java:29)
at org.apache.ibatis.builder.xml.dynamic.MixedSqlNode.apply(MixedSqlNode.java:29)
at org.apache.ibatis.builder.xml.dynamic.DynamicSqlSource.getBoundSql(DynamicSqlSource.java:37)
at org.apache.ibatis.mapping.MappedStatement.getBoundSql(MappedStatement.java:241)
at org.apache.ibatis.executor.statement.BaseStatementHandler.<init>(BaseStatementHandler.java:61)
at org.apache.ibatis.executor.statement.PreparedStatementHandler.<init>(PreparedStatementHandler.java:36)
at org.apache.ibatis.executor.statement.RoutingStatementHandler.<init>(RoutingStatementHandler.java:42)
at org.apache.ibatis.session.Configuration.newStatementHandler(Configuration.java:348)
at org.apache.ibatis.executor.SimpleExecutor.doUpdate(SimpleExecutor.java:43)
at org.apache.ibatis.executor.BaseExecutor.update(BaseExecutor.java:108)
at org.apache.ibatis.executor.CachingExecutor.update(CachingExecutor.java:75)
at org.apache.ibatis.session.defaults.DefaultSqlSession.update(DefaultSqlSession.java:145)
... 51 more












　　对应配置为:

<if test="downNum!=null and downNum!='null' and downNum!=''">
#{downNum}
</if>
　　错误原因是使用了判断String的条件判断数字类型，正确方式是:

<if test="downNum>=0">
#{downNum}
</if>