我正在尝试使用检测代码生成随机数。为此,我添加了以下表达式来生成随机数。但它正在抛出一个验证错误,如下所示。
method.addLocalVariable("instMethod_correlationId", CtClass.longType);
beforeBuilder.append("instMethod_correlationId = Long.valueOf(String.valueOf(System.nanoTime()) + String.valueOf(Math.round(Math.random())));");
我添加了一个long变量并分配了上面生成的值。但是我在运行期间遇到了异常。但是,如果我在正常项目中运行相同的数字生成,它不会抛出任何异常。
java.lang.VerifyError: Bad type on operand stack
Exception Details:
Location:
org/h2/jdbc/JdbcConnection.prepareStatement(Ljava/lang/String;)Ljava/sql/PreparedStatement; @38: i2l
Reason:
Type 'java/lang/Long' (current frame, stack[0]) is not assignable to integer
Current Frame:
bci: @38
flags: { }
locals: { 'org/h2/jdbc/JdbcConnection', 'java/lang/String', top, long, long_2nd }
stack: { 'java/lang/Long' }
Bytecode:
0000000: b803 6c42 bb03 6e59 b703 6fb8 036c b803
0000010: 73b6 0376 b803 7cb8 0380 b803 73b6 0376
0000020: b603 81b8 0386 8537 05b8 038b b803 8e16
0000030: 0513 0390 b603 94bb 0396 59b7 0397 3a07
0000040: 1907 1303 992b b903 9d03 0057 b803 8bb8
0000050: 038e 1605 1303 9f19 07b6 03a2 2a06 b600
0000060: 113d 2ab6 002a 9900 272a 1237 061c bb00
0000070: 1659 b700 1712 38b6 0019 2a2b b600 1db6
0000080: 0019 1234 b600 19b6 0020 b600 2d2a b600
0000090: 2e2a 2bb7 0039 4cbb 003a 592a 2b1c 1103
00000a0: ebb2 0030 03b7 003b a700 0a4d 2a2c b600
00000b0: 28bf 3a09 bb03 9659 b703 973a 0a19 0a13
00000c0: 03a4 1303 a6b9 039d 0300 57b8 038b b803
00000d0: 8e16 05bb 036e 59b7 036f 1303 a8b6 0376
00000e0: b803 6c21 65b8 0373 b603 76b6 0381 190a
00000f0: b603 a219 09b0
Exception Handler Table:
bci [55, 168] => handler: 171
Stackmap Table:
full_frame(@141,{Object[#320],Object[#331],Integer,Long,Long,Object[#918]},{})
full_frame(@171,{Object[#320],Object[#331],Top,Long,Long},{Object[#322]})
full_frame(@178,{Object[#320],Object[#331],Integer,Long,Long,Object[#918]},{Object[#58]})
at org.h2.Driver.connect(Driver.java:73)
at org.apache.tomcat.jdbc.pool.PooledConnection.connectUsingDriver(PooledConnection.java:278)
at org.apache.tomcat.jdbc.pool.PooledConnection.connect(PooledConnection.java:182)
at org.apache.tomcat.jdbc.pool.ConnectionPool.createConnection(ConnectionPool.java:701)
at org.apache.tomcat.jdbc.pool.ConnectionPool.borrowConnection(ConnectionPool.java:635)
at org.apache.tomcat.jdbc.pool.ConnectionPool.getConnection(ConnectionPool.java:188)
at org.apache.tomcat.jdbc.pool.DataSourceProxy.getConnection(DataSourceProxy.java:128)
at org.wso2.carbon.user.core.claim.dao.ClaimDAO.getDialectCount(ClaimDAO.java:158)
at org.wso2.carbon.user.core.common.DefaultRealm.populateProfileAndClaimMaps(DefaultRealm.java:429)
at org.wso2.carbon.user.core.common.DefaultRealm.init(DefaultRealm.java:105)
at org.wso2.carbon.user.core.common.DefaultRealmService.initializeRealm(DefaultRealmService.java:262)
at org.user.core.common.DefaultRealmService.<init>(DefaultRealmService.java:99)
at org.user.core.common.DefaultRealmService.<init>(DefaultRealmService.java:112)
at org.user.core.internal.Activator.startDeploy(Activator.java:68)
at org.user.core.internal.BundleCheckActivator.start(BundleCheckActivator.java:61)
at org.eclipse.osgi.framework.internal.core.BundleContextImpl$1.run(BundleContextImpl.java:711)
at java.security.AccessController.doPrivileged(Native Method)
at org.eclipse.osgi.framework.internal.core.BundleContextImpl.startActivator(BundleContextImpl.java:702)
at org.eclipse.osgi.framework.internal.core.BundleContextImpl.start(BundleContextImpl.java:683)
at org.eclipse.osgi.framework.internal.core.BundleHost.startWorker(BundleHost.java:381)
at org.eclipse.osgi.framework.internal.core.AbstractBundle.resume(AbstractBundle.java:390)
at org.eclipse.osgi.framework.internal.core.Framework.resumeBundle(Framework.java:1176)
at org.eclipse.osgi.framework.internal.core.StartLevelManager.resumeBundles(StartLevelManager.java:559)
at org.eclipse.osgi.framework.internal.core.StartLevelManager.resumeBundles(StartLevelManager.java:544)
at org.eclipse.osgi.framework.internal.core.StartLevelManager.incFWSL(StartLevelManager.java:457)
at org.eclipse.osgi.framework.internal.core.StartLevelManager.doSetStartLevel(StartLevelManager.java:243)
at org.eclipse.osgi.framework.internal.core.StartLevelManager.dispatchEvent(StartLevelManager.java:438)
at org.eclipse.osgi.framework.internal.core.StartLevelManager.dispatchEvent(StartLevelManager.java:1)
at org.eclipse.osgi.framework.eventmgr.EventManager.dispatchEvent(EventManager.java:230)
at org.eclipse.osgi.framework.eventmgr.EventManager$EventThread.run(EventManager.java:340)
我应该怎么做才能克服这个问题?我在这里做错了什么?
答案 0 :(得分:2)
您似乎遇到了Javassist的字节码生成器中的错误。以下是VerifyError
报告的反汇编代码。请注意,由于异常消息中缺少常量池,实际的目标方法是从源代码中猜出的(但看起来似乎合理):
0 invokestatic [876]
3 lstore_3
4 new [878] guess: new StringBuilder
7 dup
8 invokespecial [879] guess: StringBuilder.<init>
11 invokestatic [876] guess: System.nanoTime()
14 invokestatic [883] guess: String.valueOf(long)
17 invokevirtual [886] guess: StringBuilder.append(String)
20 invokestatic [892] guess: Math.random()
23 invokestatic [896] guess: Math.round(double)
26 invokestatic [883] guess: String.valueOf(long)
29 invokevirtual [886] guess: StringBuilder.append(String)
32 invokevirtual [897] guess: StringBuilder.toString()
35 invokestatic [902] guess: Long.valueOf(String)
38 i2l
39 lstore <5>
… rest omitted
请注意,方法调用与您的源代码片段(正如static
或虚拟预期的那样匹配,并且应该是相同的参考),而位置38
处的指令,被验证者拒绝,是一条虚假的i2l
指令(从int
转换为long
)。在这个位置,应该会发生从Long
到long
的拆箱转换。由于以下lstore
指令将long
值存储到局部变量中,因此Javassist似乎正确地使用了本地变量声明。
请注意,前两条指令表明还有其他仪器发生;因为它调用与位置11
处的指令相同的方法(假设为System.nanoTime
),所以其他检测似乎用于测量方法的总体执行时间。但这不应该影响您的仪器代码。
您可以联系Javassist的作者,了解Long
拆箱是否应该有效。同时,您可以使用Long.parseLong
而不是Long.valueOf
来解决问题,以避免首先进行装箱/取消装箱。您还可以使用String.concat
而不是+
运算符从生成的代码的角度简化操作,因为这样就无需在内部处理StringBuilder
:
替换
method.addLocalVariable("instMethod_correlationId", CtClass.longType);
beforeBuilder.append("instMethod_correlationId = Long.valueOf(String.valueOf(System.nanoTime()) + String.valueOf(Math.round(Math.random())));");
与
method.addLocalVariable("instMethod_correlationId", CtClass.longType);
beforeBuilder.append("instMethod_correlationId = Long.parseLong(String.valueOf(System.nanoTime()).concat(String.valueOf(Math.round(Math.random()))));");
这应该降低对Javassist编译功能的要求,并解决原始代码片段触发的错误。