<% String datetime = request.getParameter("datetime");
String bt = request.getParameter("bt");
ResultSet rs = null;
Bean1.setsDataSource(bt+"Data");
Bean1.setsUserName("sa");
Bean1.setsPassword("sa");
String txtsql="";
String txtsql1="";
if(bt=="gfuba"){
txtsql1=" SELECT top 1 dati ,k1, BD1 - BG1, BD2 - BG2, BD3 - BG3, BD4 - BG4 FROM U_Gtjc order by dati desc";
out.print("1111");
}else(bt=="gzhuba"){
txtsql1=" SELECT top 1 dati ,k1, AD0 - AG0, AD1 - AG1 , AD2 - AG2 , AD3 - AG3 , AD4 - AG4 , AD5 - AG5 , AD6 - AG6 FROM U_Gtjc order by dati desc";
out.print("22222");
}为什么都不进if语句就直接执行else里面的呢?
String bt = request.getParameter("bt");
ResultSet rs = null;
Bean1.setsDataSource(bt+"Data");
Bean1.setsUserName("sa");
Bean1.setsPassword("sa");
String txtsql="";
String txtsql1="";
if(bt=="gfuba"){
txtsql1=" SELECT top 1 dati ,k1, BD1 - BG1, BD2 - BG2, BD3 - BG3, BD4 - BG4 FROM U_Gtjc order by dati desc";
out.print("1111");
}else(bt=="gzhuba"){
txtsql1=" SELECT top 1 dati ,k1, AD0 - AG0, AD1 - AG1 , AD2 - AG2 , AD3 - AG3 , AD4 - AG4 , AD5 - AG5 , AD6 - AG6 FROM U_Gtjc order by dati desc";
out.print("22222");
}为什么都不进if语句就直接执行else里面的呢?
解决方案 »
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String bt ="";
bt =(String)request.getParameter("bt");
if(bt == null){
bt = "";
}
ResultSet rs = null;
Bean1.setsDataSource(bt+"Data");
Bean1.setsUserName("sa");
Bean1.setsPassword("sa");
String txtsql="";
String txtsql1="";
if(bt=="gfuba"){
txtsql1=" SELECT top 1 dati ,k1, BD1 - BG1, BD2 - BG2, BD3 - BG3, BD4 - BG4 FROM U_Gtjc order by dati desc";
out.print("1111");
}else(bt=="gzhuba"){
txtsql1=" SELECT top 1 dati ,k1, AD0 - AG0, AD1 - AG1 , AD2 - AG2 , AD3 - AG3 , AD4 - AG4 , AD5 - AG5 , AD6 - AG6 FROM U_Gtjc order by dati desc";
out.print("22222");
} 你先试试这样能进IF不?
要用equals
因为是string型!
写的有问题啊,改用 if(bt.equals("gfuba"))
在使用bt时,最好应判断空,再trim,最后才能进行比较(equals).
建议自己写一个扩展一个即可trim又可将null变为空串的方法
如:
public String trim(String str){
if(str == null) retrun "";
else return str.trim();}最后才能安全的进行比较:就是楼上回复的,要使用 bt.equals("").字符串的比较是对象比较,== 是进行内存地址比较,当前是不相等的.
这是两个String当然不相等 直接进入else了比较内容是否相等要用equals(记住要判断NULL的情况)
txtsql1=" SELECT top 1 dati ,k1, BD1 - BG1, BD2 - BG2, BD3 - BG3, BD4 - BG4 FROM U_Gtjc order by dati desc";
out.print("1111");
}else(bt!=null && "gzhuba".equals(bt)){
txtsql1=" SELECT top 1 dati ,k1, AD0 - AG0, AD1 - AG1 , AD2 - AG2 , AD3 - AG3 , AD4 - AG4 , AD5 - AG5 , AD6 - AG6 FROM U_Gtjc order by dati desc";
out.print("22222");
}
String bt = (String)request.getParameter("bt");
if(bt==null){ bt="gzhuba";}
ResultSet rs = null;
Bean1.setsDataSource(bt+"Data");
Bean1.setsUserName("sa");
Bean1.setsPassword("sa");
String txtsql="";
String txtsql1="";
/*if(bt!=null && "gfuba".equals(bt)){
txtsql1=" SELECT top 1 dati ,k1, BD1 - BG1, BD2 - BG2, BD3 - BG3, BD4 - BG4 FROM U_Gtjc order by dati desc";
out.print("1111");
}else(bt!=null && "gzhuba".equals(bt)){
txtsql1=" SELECT top 1 dati ,k1, AD0 - AG0, AD1 - AG1 , AD2 - AG2 , AD3 - AG3 , AD4 - AG4 , AD5 - AG5 , AD6 - AG6 FROM U_Gtjc order by dati desc";
out.print("22222");
}*/为什么我把红字的那段屏蔽了之后就没有错误了, 加上之后就提示:
org.apache.jasper.JasperException: Unable to compile class for JSPAn error occurred at line: 23 in the jsp file: /pmxs_gt/data.jsp
Generated servlet error:
Syntax error, insert "AssignmentOperator ArrayInitializer" to complete ArrayInitializerAssignementAn error occurred at line: 23 in the jsp file: /pmxs_gt/data.jsp
Generated servlet error:
Syntax error, insert ";" to complete Statement
txtsql1=" SELECT top 1 dati ,k1, BD1 - BG1, BD2 - BG2, BD3 - BG3, BD4 - BG4 FROM U_Gtjc order by dati desc";
out.print("1111");
}else(bt!=null && bt.equals("gfuba")){
txtsql1=" SELECT top 1 dati ,k1, AD0 - AG0, AD1 - AG1 , AD2 - AG2 , AD3 - AG3 , AD4 - AG4 , AD5 - AG5 , AD6 - AG6 FROM U_Gtjc order by dati desc";
out.print("22222");
}
试试!
String bt = (String)request.getParameter("bt");
if(bt==null){ bt="gzhuba";}
ResultSet rs = null;
Bean1.setsDataSource(bt+"Data");
Bean1.setsUserName("sa");
Bean1.setsPassword("sa");
String txtsql="";
String txtsql1="";
/*if(bt!=null && "gfuba".equals(bt)){
txtsql1=" SELECT top 1 dati ,k1, BD1 - BG1, BD2 - BG2, BD3 - BG3, BD4 - BG4 FROM U_Gtjc order by dati desc";
out.print("1111");
}else(bt!=null && "gzhuba".equals(bt)){
txtsql1=" SELECT top 1 dati ,k1, AD0 - AG0, AD1 - AG1 , AD2 - AG2 , AD3 - AG3 , AD4 - AG4 , AD5 - AG5 , AD6 - AG6 FROM U_Gtjc order by dati desc";
out.print("22222");
}*/ 为什么我把红字的那段屏蔽了之后就没有错误了, 加上之后就提示:
org.apache.jasper.JasperException: Unable to compile class for JSP An error occurred at line: 23 in the jsp file: /pmxs_gt/data.jsp
Generated servlet error:
Syntax error, insert "AssignmentOperator ArrayInitializer" to complete ArrayInitializerAssignement An error occurred at line: 23 in the jsp file: /pmxs_gt/data.jsp
Generated servlet error:
Syntax error, insert ";" to complete Statement
大侠帮忙看看吧