struts2接收表单更新数据库出现问题：java.sql.SQLException: Column 'username' cannot be null

背后有我 2016-05-26 04:32:43
求指教，下面是完整代码
index.jsp:
<body>
<h1>填写表单</h1><hr>
<form action="addUser.action" method="post">
id:<input type="text" name="id"><br>
Username:<input type="text" name="username"><br>
Password:<input type="password" name="password"><br>
<input type="submit" value="添加"> 
<a><input type="button">查看输入</a>
</form>
</body>

public class AddUserAction extends ActionSupport{

private static final long serialVersionUID = 1L;
private Connection conn=null;
private PreparedStatement pstmt=null;

public String execute() throws Exception{
User u=new User();
addUser(u);
return SUCCESS;
}

public void addUser(User u) throws SQLException{

String sql="insert into users(id,username,password) values(?,?,?)";
MYSQL_Conn mc=new MYSQL_Conn();
conn=mc.getConn();
pstmt=conn.prepareStatement(sql);
pstmt.setInt(1, u.getId());
pstmt.setString(2, u.getUsername());
pstmt.setString(3, u.getPassword());
pstmt.execute();
}

}

struts.xml:
<action name="addUser" class="com.action.AddUserAction">
<result name="success">/allUsers.jsp</result>
<result name="error">/error.jsp</result>
</action>

报错信息：
type Exception report

message

description The server encountered an internal error () that prevented it from fulfilling this request.

exception

java.sql.SQLException: Column 'username' cannot be null
com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:2921)
com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:1570)
com.mysql.jdbc.ServerPreparedStatement.serverExecute(ServerPreparedStatement.java:1085)
com.mysql.jdbc.ServerPreparedStatement.executeInternal(ServerPreparedStatement.java:670)
com.mysql.jdbc.PreparedStatement.execute(PreparedStatement.java:770)
com.action.AddUserAction.addUser(AddUserAction.java:30)
com.action.AddUserAction.execute(AddUserAction.java:17)
sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
java.lang.reflect.Method.invoke(Method.java:597)
ognl.OgnlRuntime.invokeMethod(OgnlRuntime.java:891)
ognl.OgnlRuntime.callAppropriateMethod(OgnlRuntime.java:1293)
ognl.ObjectMethodAccessor.callMethod(ObjectMethodAccessor.java:68)
com.opensymphony.xwork2.ognl.accessor.XWorkMethodAccessor.callMethodWithDebugInfo(XWorkMethodAccessor.java:117)
com.opensymphony.xwork2.ognl.accessor.XWorkMethodAccessor.callMethod(XWorkMethodAccessor.java:108)
ognl.OgnlRuntime.callMethod(OgnlRuntime.java:1369)
ognl.ASTMethod.getValueBody(ASTMethod.java:90)
ognl.SimpleNode.evaluateGetValueBody(SimpleNode.java:212)
ognl.SimpleNode.getValue(SimpleNode.java:258)
ognl.Ognl.getValue(Ognl.java:494)
ognl.Ognl.getValue(Ognl.java:458)
com.opensymphony.xwork2.ognl.OgnlUtil$2.execute(OgnlUtil.java:309)
com.opensymphony.xwork2.ognl.OgnlUtil.compileAndExecute(OgnlUtil.java:340)
com.opensymphony.xwork2.ognl.OgnlUtil.getValue(OgnlUtil.java:307)
com.opensymphony.xwork2.DefaultActionInvocation.invokeAction(DefaultActionInvocation.java:423)
com.opensymphony.xwork2.DefaultActionInvocation.invokeActionOnly(DefaultActionInvocation.java:287)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:250)
org.apache.struts2.interceptor.DeprecationInterceptor.intercept(DeprecationInterceptor.java:41)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)
org.apache.struts2.interceptor.debugging.DebuggingInterceptor.intercept(DebuggingInterceptor.java:256)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)
com.opensymphony.xwork2.interceptor.DefaultWorkflowInterceptor.doIntercept(DefaultWorkflowInterceptor.java:167)
com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)
com.opensymphony.xwork2.validator.ValidationInterceptor.doIntercept(ValidationInterceptor.java:265)
org.apache.struts2.interceptor.validation.AnnotationValidationInterceptor.doIntercept(AnnotationValidationInterceptor.java:76)
com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)
com.opensymphony.xwork2.interceptor.ConversionErrorInterceptor.intercept(ConversionErrorInterceptor.java:138)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)
com.opensymphony.xwork2.interceptor.ParametersInterceptor.doIntercept(ParametersInterceptor.java:229)
com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)
com.opensymphony.xwork2.interceptor.ParametersInterceptor.doIntercept(ParametersInterceptor.java:229)
com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)
com.opensymphony.xwork2.interceptor.StaticParametersInterceptor.intercept(StaticParametersInterceptor.java:191)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)
org.apache.struts2.interceptor.MultiselectInterceptor.intercept(MultiselectInterceptor.java:73)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)
org.apache.struts2.interceptor.DateTextFieldInterceptor.intercept(DateTextFieldInterceptor.java:125)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)
org.apache.struts2.interceptor.CheckboxInterceptor.intercept(CheckboxInterceptor.java:91)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)
org.apache.struts2.interceptor.FileUploadInterceptor.intercept(FileUploadInterceptor.java:253)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)
com.opensymphony.xwork2.interceptor.ModelDrivenInterceptor.intercept(ModelDrivenInterceptor.java:100)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)
com.opensymphony.xwork2.interceptor.ScopedModelDrivenInterceptor.intercept(ScopedModelDrivenInterceptor.java:141)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)
com.opensymphony.xwork2.interceptor.ChainingInterceptor.intercept(ChainingInterceptor.java:145)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)
com.opensymphony.xwork2.interceptor.PrepareInterceptor.doIntercept(PrepareInterceptor.java:171)
com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)
com.opensymphony.xwork2.interceptor.I18nInterceptor.intercept(I18nInterceptor.java:139)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)
org.apache.struts2.interceptor.ServletConfigInterceptor.intercept(ServletConfigInterceptor.java:164)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)
com.opensymphony.xwork2.interceptor.AliasInterceptor.intercept(AliasInterceptor.java:193)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)
com.opensymphony.xwork2.interceptor.ExceptionMappingInterceptor.intercept(ExceptionMappingInterceptor.java:189)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244)
org.apache.struts2.impl.StrutsActionProxy.execute(StrutsActionProxy.java:54)
org.apache.struts2.dispatcher.Dispatcher.serviceAction(Dispatcher.java:564)
org.apache.struts2.dispatcher.ng.ExecuteOperations.executeAction(ExecuteOperations.java:81)
org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter.doFilter(StrutsPrepareAndExecuteFilter.java:99)


note The full stack trace of the root cause is available in the Apache Tomcat/6.0.32 logs.


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I wanna be the JVM 2017-09-21
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应该缺少数据的获取方式，，利用对象传输数据的吧？要不就少了setget方法
teddyboy1992 2016-05-28
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检查下User对象中username有get和set方法吗？或者名称有问题，查查看！你的是缺少get方法！！
背后有我 2016-05-28
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终于解决了谢谢大神们 附上代码： public class AddUserAction extends ActionSupport{ private static final long serialVersionUID = 1L; private Connection conn=null; private PreparedStatement pstmt=null; private User user; public void setUser(User user) { this.user = user; } public User getUser() { return user; } public String execute() throws Exception{ String sql="insert into users(username,password) values(?,?)"; MYSQL_Conn mc=new MYSQL_Conn(); conn=mc.getConn(); pstmt=conn.prepareStatement(sql); pstmt.setString(1, user.getUsername()); pstmt.setString(2, user.getPassword()); pstmt.executeUpdate(); return SUCCESS; } public void addUser(User u) throws SQLException{ } } <form action="addUser.action" method="post"> Username:<input type="text" name="user.username"><br> Password:<input type="password" name="user.password"><br> <input type="submit" value="添加">  <a><input type="button">查看输入</a> </form>
阿拉曼无悔 2016-05-27
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sturts 接受参数如果想要new ,那么你需要modelDriven方式,那么你需要implements ModelDriven接口，重写getModel方法， 或者使用request.getParameter(),或者使用domainmodel
nikyotensai 2016-05-27
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用户名不能为空
背后有我 2016-05-27
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不太懂，能具体指出来吗？
昵称不知道怎么取 2016-05-27
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new对象之后，往里面set值进行时，一般加非空校验
背后有我 2016-05-27
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public class AddUserAction extends ActionSupport{ private static final long serialVersionUID = 1L; private Connection conn=null; private PreparedStatement pstmt=null; private User user; public void setUser(User user) { this.user = user; } public String execute() throws Exception{ addUser(user); return SUCCESS; } public void addUser(User u) throws SQLException{ String sql="insert into users(id,username,password) values(?,?,?)"; MYSQL_Conn mc=new MYSQL_Conn(); conn=mc.getConn(); pstmt=conn.prepareStatement(sql); pstmt.setInt(1, u.getId()); pstmt.setString(2, u.getUsername()); pstmt.setString(3, u.getPassword()); pstmt.execute(); } } 修改了，怎么会又出现空指针错误 java.lang.NullPointerException com.action.AddUserAction.addUser(AddUserAction.java:31) com.action.AddUserAction.execute(AddUserAction.java:22) sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) java.lang.reflect.Method.invoke(Method.java:597) ognl.OgnlRuntime.invokeMethod(OgnlRuntime.java:891) ognl.OgnlRuntime.callAppropriateMethod(OgnlRuntime.java:1293) ognl.ObjectMethodAccessor.callMethod(ObjectMethodAccessor.java:68) com.opensymphony.xwork2.ognl.accessor.XWorkMethodAccessor.callMethodWithDebugInfo(XWorkMethodAccessor.java:117) com.opensymphony.xwork2.ognl.accessor.XWorkMethodAccessor.callMethod(XWorkMethodAccessor.java:108) ognl.OgnlRuntime.callMethod(OgnlRuntime.java:1369) ognl.ASTMethod.getValueBody(ASTMethod.java:90) ognl.SimpleNode.evaluateGetValueBody(SimpleNode.java:212) ognl.SimpleNode.getValue(SimpleNode.java:258) ognl.Ognl.getValue(Ognl.java:494) ognl.Ognl.getValue(Ognl.java:458) com.opensymphony.xwork2.ognl.OgnlUtil$2.execute(OgnlUtil.java:309) com.opensymphony.xwork2.ognl.OgnlUtil.compileAndExecute(OgnlUtil.java:340) com.opensymphony.xwork2.ognl.OgnlUtil.getValue(OgnlUtil.java:307) com.opensymphony.xwork2.DefaultActionInvocation.invokeAction(DefaultActionInvocation.java:423) com.opensymphony.xwork2.DefaultActionInvocation.invokeActionOnly(DefaultActionInvocation.java:287) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:250) org.apache.struts2.interceptor.DeprecationInterceptor.intercept(DeprecationInterceptor.java:41) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244) org.apache.struts2.interceptor.debugging.DebuggingInterceptor.intercept(DebuggingInterceptor.java:256) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244) com.opensymphony.xwork2.interceptor.DefaultWorkflowInterceptor.doIntercept(DefaultWorkflowInterceptor.java:167) com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244) com.opensymphony.xwork2.validator.ValidationInterceptor.doIntercept(ValidationInterceptor.java:265) org.apache.struts2.interceptor.validation.AnnotationValidationInterceptor.doIntercept(AnnotationValidationInterceptor.java:76) com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244) com.opensymphony.xwork2.interceptor.ConversionErrorInterceptor.intercept(ConversionErrorInterceptor.java:138) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244) com.opensymphony.xwork2.interceptor.ParametersInterceptor.doIntercept(ParametersInterceptor.java:229) com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244) com.opensymphony.xwork2.interceptor.ParametersInterceptor.doIntercept(ParametersInterceptor.java:229) com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244) com.opensymphony.xwork2.interceptor.StaticParametersInterceptor.intercept(StaticParametersInterceptor.java:191) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244) org.apache.struts2.interceptor.MultiselectInterceptor.intercept(MultiselectInterceptor.java:73) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244) org.apache.struts2.interceptor.DateTextFieldInterceptor.intercept(DateTextFieldInterceptor.java:125) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244) org.apache.struts2.interceptor.CheckboxInterceptor.intercept(CheckboxInterceptor.java:91) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244) org.apache.struts2.interceptor.FileUploadInterceptor.intercept(FileUploadInterceptor.java:253) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244) com.opensymphony.xwork2.interceptor.ModelDrivenInterceptor.intercept(ModelDrivenInterceptor.java:100) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244) com.opensymphony.xwork2.interceptor.ScopedModelDrivenInterceptor.intercept(ScopedModelDrivenInterceptor.java:141) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244) com.opensymphony.xwork2.interceptor.ChainingInterceptor.intercept(ChainingInterceptor.java:145) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244) com.opensymphony.xwork2.interceptor.PrepareInterceptor.doIntercept(PrepareInterceptor.java:171) com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244) com.opensymphony.xwork2.interceptor.I18nInterceptor.intercept(I18nInterceptor.java:139) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244) org.apache.struts2.interceptor.ServletConfigInterceptor.intercept(ServletConfigInterceptor.java:164) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244) com.opensymphony.xwork2.interceptor.AliasInterceptor.intercept(AliasInterceptor.java:193) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244) com.opensymphony.xwork2.interceptor.ExceptionMappingInterceptor.intercept(ExceptionMappingInterceptor.java:189) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:244) org.apache.struts2.impl.StrutsActionProxy.execute(StrutsActionProxy.java:54) org.apache.struts2.dispatcher.Dispatcher.serviceAction(Dispatcher.java:564) org.apache.struts2.dispatcher.ng.ExecuteOperations.executeAction(ExecuteOperations.java:81) org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter.doFilter(StrutsPrepareAndExecuteFilter.java:99)
fanyuanwaifdl 2016-05-26
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实例化了对象 二对象中username的属性没赋值 为null 数据库设置为not null 必然抛出该错误
github_35124733 2016-05-26
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参数没有接受，new user只是你自己创建的对象而已，是个空对象
尼古拉斯-全蛋 2016-05-26
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username不能为空，你在这里new了一个空的user进去，User u=new User();addUser(u);
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