d != java.lang.string_java.util.IllegalFormatConversionException: d != java.lang.String-优快云博客

本文介绍了在使用 Java 的 String.format 方法时的一个常见错误——非法格式转换异常 (IllegalFormatConversionException)，该异常通常发生在尝试将字符串格式化为数字时。文章详细解释了错误原因，并提供了正确的格式化方法。

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1、错误描述

java.util.IllegalFormatConversionException: d != java.lang.String

at java.util.Formatter$FormatSpecifier.failConversion(Formatter.java:4045)

at java.util.Formatter$FormatSpecifier.printInteger(Formatter.java:2748)

at java.util.Formatter$FormatSpecifier.print(Formatter.java:2702)

at java.util.Formatter.format(Formatter.java:2488)

at java.util.Formatter.format(Formatter.java:2423)

at java.lang.String.format(String.java:2792)

at org.springframework.cglib.proxy.MethodProxy.invoke(MethodProxy.java:204)

at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.invokeJoinpoint(CglibAopProxy.java:708)

at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:157)

at org.springframework.transaction.interceptor.TransactionInterceptor$1.proceedWithInvocation(TransactionInterceptor.java:98)

at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:262)

at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:95)

at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)

at org.springframework.aop.interceptor.ExposeInvocationInterceptor.invoke(ExposeInvocationInterceptor.java:92)

at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)

at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:41)

at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:20)

at org.springframework.test.context.junit4.statements.RunBeforeTestMethodCallbacks.evaluate(RunBeforeTestMethodCallbacks.java:74)

at org.springframework.test.context.junit4.statements.RunAfterTestMethodCallbacks.evaluate(RunAfterTestMethodCallbacks.java:83)

at org.springframework.test.context.junit4.statements.SpringRepeat.evaluate(SpringRepeat.java:72)

at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:233)

at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:87)

at org.junit.runners.ParentRunner$3.run(ParentRunner.java:193)

at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:52)

at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:191)

at org.junit.runners.ParentRunner.access$000(ParentRunner.java:42)

at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:184)

at org.springframework.test.context.junit4.statements.RunBeforeTestClassCallbacks.evaluate(RunBeforeTestClassCallbacks.java:61)

at org.springframework.test.context.junit4.statements.RunAfterTestClassCallbacks.evaluate(RunAfterTestClassCallbacks.java:71)

at org.junit.runners.ParentRunner.run(ParentRunner.java:236)

at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.run(SpringJUnit4ClassRunner.java:176)

at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:50)

at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)

at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:467)

at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:683)

at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:390)

at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:197)

2、错误描述

在拼接SQL语句时，需要用到占位符，这里用到字符，我使用in (%d)

在利用String.format(sql,"?"); 这样出现错误，因为%d是针对数值来讲的，而字符是用的%s

3、解决办法

(1)如果是字符的话，利用%s

(2)如果是数值的话，利用%d