错误信息：

nested exception is org.apache.ibatis.exceptions.PersistenceException: \r\n### Error querying database.  Cause: java.lang.NumberFormatException: For input string: \"P\"\r\n### Cause: java.lang.NumberFormatException: For input string: \"P\"

### Cause: java.lang.NumberFormatException: For input string: "P"] with root cause

java.lang.NumberFormatException: For input string: "P"
    at sun.misc.FloatingDecimal.readJavaFormatString(FloatingDecimal.java:2043) ~[na:1.8.0_261]
    at sun.misc.FloatingDecimal.parseDouble(FloatingDecimal.java:110) ~[na:1.8.0_261]
    at java.lang.Double.parseDouble(Double.java:538) ~[na:1.8.0_261]
    at org.apache.ibatis.ognl.OgnlOps.doubleValue(OgnlOps.java:253) ~[mybatis-3.5.5.jar:3.5.5]
    at org.apache.ibatis.ognl.OgnlOps.compareWithConversion(OgnlOps.java:104) ~[mybatis-3.5.5.jar:3.5.5]
    at org.apache.ibatis.ognl.OgnlOps.isEqual(OgnlOps.java:153) ~[mybatis-3.5.5.jar:3.5.5]
    at org.apache.ibatis.ognl.OgnlOps.equal(OgnlOps.java:814) ~[mybatis-3.5.5.jar:3.5.5]
    at org.apache.ibatis.ognl.ASTEq.getValueBody(ASTEq.java:52) ~[mybatis-3.5.5.jar:3.5.5]
    at org.apache.ibatis.ognl.SimpleNode.evaluateGetValueBody(SimpleNode.java:212) ~[mybatis-3.5.5.jar:3.5.5]
    at org.apache.ibatis.ognl.SimpleNode.getValue(SimpleNode.java:258) ~[mybatis-3.5.5.jar:3.5.5]
    at org.apache.ibatis.ognl.ASTAnd.getValueBody(ASTAnd.java:61) ~[mybatis-3.5.5.jar:3.5.5]
    at org.apache.ibatis.ognl.SimpleNode.evaluateGetValueBody(SimpleNode.java:212) ~[mybatis-3.5.5.jar:3.5.5]
    at org.apache.ibatis.ognl.SimpleNode.getValue(SimpleNode.java:258) ~[mybatis-3.5.5.jar:3.5.5]
    at org.apache.ibatis.ognl.Ognl.getValue(Ognl.java:560) ~[mybatis-3.5.5.jar:3.5.5]
    at org.apache.ibatis.ognl.Ognl.getValue(Ognl.java:524) ~[mybatis-3.5.5.jar:3.5.5]
    at org.apache.ibatis.scripting.xmltags.OgnlCache.getValue(OgnlCache.java:46) ~[mybatis-3.5.5.jar:3.5.5]
    at org.apache.ibatis.scripting.xmltags.ExpressionEvaluator.evaluateBoolean(ExpressionEvaluator.java:32) ~[mybatis-3.5.5.jar:3.5.5]
    at org.apache.ibatis.scripting.xmltags.IfSqlNode.apply(IfSqlNode.java:34) ~[mybatis-3.5.5.jar:3.5.5]
    at org.apache.ibatis.scripting.xmltags.MixedSqlNode.lambda$apply$0(MixedSqlNode.java:32) ~[mybatis-3.5.5.jar:3.5.5]
    at java.util.ArrayList.forEach(ArrayList.java:1259) ~[na:1.8.0_261]
    at org.apache.ibatis.scripting.xmltags.MixedSqlNode.apply(MixedSqlNode.java:32) ~[mybatis-3.5.5.jar:3.5.5]
...

条件查询代码

          <if test="type != null and type == 'P'">
              and f.type  = 'P'
          </if>

修改为：

          <if test="type  != null and type == 'P'.toString()">
              and f.type  = 'P'
          </if>