我猜我收到此错误是因为该字符串正在尝试对 null
值进行子串化。但是 ".length() > 0"
部分不会消除这个问题吗?
这是 Java 代码段:
if (itemdescription.length() > 0) {
pstmt2.setString(3, itemdescription.substring(0,38));
}
else {
pstmt2.setString(3, "_");
}
我收到了这个错误:
java.lang.StringIndexOutOfBoundsException: String index out of range: 38
at java.lang.String.substring(Unknown Source)
at MASInsert2.itemimport(MASInsert2.java:192)
at MASInsert2.processRequest(MASInsert2.java:125)
at MASInsert2.doGet(MASInsert2.java:219)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:627)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:269)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:188)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:213)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:172)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:117)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:108)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:174)
at org.apache.coyote.http11.Http11AprProcessor.process(Http11AprProcessor.java:835)
at org.apache.coyote.http11.Http11AprProtocol$Http11ConnectionHandler.process(Http11AprProtocol.java:640)
at org.apache.tomcat.util.net.AprEndpoint$Worker.run(AprEndpoint.java:1286)
at java.lang.Thread.run(Unknown Source)
最佳答案
很遗憾 substring
没有以处理短字符串的方式实现 - 就像在其他语言中一样,例如 python 。
好的,我们无法更改它,并且每次使用 substr
时都必须考虑这种极端情况,而不是 if-else 子句,我会选择这个较短的变体:
myText.substring(0, Math.min(6, myText.length()))
关于Java 子字符串 : 'string index out of range' ,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/953527/