tomcat启动dubbo报IO异常

严重: Servlet [springDispatcher] in web application [/dubbo-service] threw load() exception
java.io.IOException: invalid constant type: 15
    at javassist.bytecode.ConstPool.readOne(ConstPool.java:1113)
    at javassist.bytecode.ConstPool.read(ConstPool.java:1056)
    at javassist.bytecode.ConstPool.<init>(ConstPool.java:150)
    at javassist.bytecode.ClassFile.read(ClassFile.java:765)
    at javassist.bytecode.ClassFile.<init>(ClassFile.java:109)
    at javassist.CtClassType.getClassFile2(CtClassType.java:191)
    at javassist.CtClassType.subtypeOf(CtClassType.java:304)
    at javassist.CtClassType.subtypeOf(CtClassType.java:319)
    at javassist.compiler.MemberResolver.compareSignature(MemberResolver.java:248)
    at javassist.compiler.MemberResolver.lookupMethod(MemberResolver.java:120)
    at javassist.compiler.MemberResolver.lookupMethod(MemberResolver.java:97)
    at javassist.compiler.TypeChecker.atMethodCallCore(TypeChecker.java:711)
    at javassist.compiler.TypeChecker.atCallExpr(TypeChecker.java:688)
    at javassist.compiler.JvstTypeChecker.atCallExpr(JvstTypeChecker.java:157)
    at javassist.compiler.ast.CallExpr.accept(CallExpr.java:46)
    at javassist.compiler.JvstTypeChecker.atCastToWrapper(JvstTypeChecker.java:126)
    at javassist.compiler.JvstTypeChecker.atCastExpr(JvstTypeChecker.java:98)
    at javassist.compiler.ast.CastExpr.accept(CastExpr.java:55)
    at javassist.compiler.CodeGen.doTypeCheck(CodeGen.java:242)
    at javassist.compiler.CodeGen.compileExpr(CodeGen.java:229)
    at javassist.compiler.CodeGen.atReturnStmnt2(CodeGen.java:598)
    at javassist.compiler.JvstCodeGen.atReturnStmnt(JvstCodeGen.java:425)
    at javassist.compiler.CodeGen.atStmnt(CodeGen.java:363)
    at javassist.compiler.ast.Stmnt.accept(Stmnt.java:50)
    at 
javassist.compiler.CodeGen.atStmnt(CodeGen.java:351)
    at javassist.compiler.ast.Stmnt.accept(Stmnt.java:50)
    at javassist.compiler.CodeGen.atIfStmnt(CodeGen.java:391)
    at javassist.compiler.CodeGen.atStmnt(CodeGen.java:355)
    at javassist.compiler.ast.Stmnt.accept(Stmnt.java:50)
    at javassist.compiler.CodeGen.atStmnt(CodeGen.java:351)
    at javassist.compiler.ast.Stmnt.accept(Stmnt.java:50)
    at javassist.compiler.MemberCodeGen.atTryStmnt(MemberCodeGen.java:204)
    at javassist.compiler.CodeGen.atStmnt(CodeGen.java:367)
    at javassist.compiler.ast.Stmnt.accept(Stmnt.java:50)
    at javassist.compiler.CodeGen.atStmnt(CodeGen.java:351)
    at javassist.compiler.ast.Stmnt.accept(Stmnt.java:50)
    at javassist.compiler.CodeGen.atMethodBody(CodeGen.java:292)
    at javassist.compiler.CodeGen.atMethodDecl(CodeGen.java:274)
    at javassist.compiler.ast.MethodDecl.accept(MethodDecl.java:44)
    at javassist.compiler.Javac.compileMethod(Javac.java:169)
    at javassist.compiler.Javac.compile(Javac.java:95)
    at javassist.CtNewMethod.make(CtNewMethod.java:74)
    at javassist.CtNewMethod.make(CtNewMethod.java:45)
    at com.alibaba.dubbo.common.bytecode.ClassGenerator.toClass(ClassGenerator.java:318)
    at com.alibaba.dubbo.common.bytecode.Wrapper.makeWrapper(Wrapper.java:346)
    at com.alibaba.dubbo.common.bytecode.Wrapper.getWrapper(Wrapper.java:89)
    at com.alibaba.dubbo.config.ServiceConfig.doExportUrlsFor1Protocol(ServiceConfig.java:426)
    at com.alibaba.dubbo.config.ServiceConfig.doExportUrls(ServiceConfig.java:281)
    at com.alibaba.dubbo.config.ServiceConfig.doExport(ServiceConfig.java:242)
    at com.alibaba.dubbo.config.ServiceConfig.export(ServiceConfig.java:143)

启动dubbo项目报错如上，原因为：

dubbo2.5.3版本调用javassist编译字节码出错，项目中使用的是jdk1.8，判断为javassist版本问题，将依赖javassist-3.15.0-GA去掉，引入更高版本直到javassist-3.21.0-GA。

<dependency>
            <groupId>org.javassist</groupId>
            <artifactId>javassist</artifactId>
            <version>3.21.0-GA</version>
</dependency>

<dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>dubbo</artifactId>
            <version>2.5.3</version>
            <exclusions>
                <exclusion>
                    <artifactId>spring</artifactId>
                    <groupId>org.springframework</groupId>
                </exclusion>
                <exclusion>
                    <artifactId>javassist</artifactId>
                    <groupId>org.javassist</groupId>
                </exclusion>
            </exclusions>
</dependency>