ssh整合專案，做單元測試時測試hibernate查詢物件關係是否成功時，列印物件報了錯：

org.hibernate.LazyInitializationException: could not initialize proxy - no Session
	at org.hibernate.proxy.AbstractLazyInitializer.initialize(AbstractLazyInitializer.java:148)
	at org.hibernate.proxy.AbstractLazyInitializer.getImplementation(AbstractLazyInitializer.java:266)
	at org.hibernate.proxy.pojo.javassist.JavassistLazyInitializer.invoke(JavassistLazyInitializer.java:68)
	at com.im.domain.Info_$$_jvste59_0.toString(Info_$$_jvste59_0.java)
	at java.lang.String.valueOf(String.java:2994)
	at java.io.PrintStream.println(PrintStream.java:821)
	at com.im.test.HibernateTest.fun4(HibernateTest.java:57)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:498)
	at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)
	at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
	at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)
	at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
	at org.springframework.test.context.junit4.statements.RunBeforeTestMethodCallbacks.evaluate(RunBeforeTestMethodCallbacks.java:75)
	at org.springframework.test.context.junit4.statements.RunAfterTestMethodCallbacks.evaluate(RunAfterTestMethodCallbacks.java:86)
	at org.springframework.test.context.junit4.statements.SpringRepeat.evaluate(SpringRepeat.java:84)
	at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)
	at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:254)
	at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:89)
	at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
	at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
	at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
	at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
	at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
	at org.springframework.test.context.junit4.statements.RunBeforeTestClassCallbacks.evaluate(RunBeforeTestClassCallbacks.java:61)
	at org.springframework.test.context.junit4.statements.RunAfterTestClassCallbacks.evaluate(RunAfterTestClassCallbacks.java:70)
	at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
	at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.run(SpringJUnit4ClassRunner.java:193)
	at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:86)
	at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
	at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:538)
	at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:760)
	at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:460)
	at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:206)

 

沒錯就是System.out.println("");，因為測試了其他service方法都沒有報錯，然後發現這個問題：

at java.io.PrintStream.println(PrintStream.java:821)

這是要坑死。

原因：ssh使用了動態代理技術，而列印物件需要呼叫toString方法，導致觸發代理物件中的invoke方法。而在invoke方法中：

  public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
        String methodname = method.getName();
        String classname = method.getDeclaringClass().getName();
        //獲得和配置檔案的關聯性
        Configuration configuration = new Configuration();
        //獲得mapper封裝相關內容
        Map<String, Mapper> mapperMap = configuration.getMapperMap();
        //獲得資料庫連線物件
        ComboPooledDataSource dataSource = configuration.getDataSource();
        System.out.println("===");
        System.out.println("資料來源物件："+ dataSource);
        Connection conn = dataSource.getConnection();
        Mapper mapper = mapperMap.get(classname + "." + methodname);
        String sql = mapper.getSqlString();
        System.out.println("sql語句"+sql);
        //處理resultSet
        List<Object> objects = Execute.selectList(mapper, conn);
        return objects;
    }
 

由於method方法是toString,生成的key值無法在mapperMap找到對應的mapper物件，此時mapper為空。

參考：https://blog.csdn.net/weixin_42583093/article/details/82110059