帶有jsp：useBean的Javabean。它們?nèi)绾喂ぷ?？我不明?/h1>
瀏覽：130日期：2024-04-20 10:08:06
如何解決帶有jsp：useBean的Javabean。它們?nèi)绾喂ぷ鳎课也幻靼祝?p>我在index.jsp和Servlet之間又做了一個(gè)jsp文件： <jsp:useBean scope='session'/><jsp:setProperty name='binop' property='*'/>.
這做到了“魔術(shù)”。
解決方法 我必須使用Java bean從jsp文件中獲取2個(gè)數(shù)字和一個(gè)運(yùn)算。提交數(shù)字后，將它們從該Java Bean帶到servlet并返回它們的結(jié)果。問題是Javabean字段永遠(yuǎn)不會(huì)用文本框中寫的數(shù)字來完成。所以，我有了index.jsp的主體：
<html><head> <meta http-equiv='Content-Type' content='text/html; charset=UTF-8'> <title>JSP Page</title> <link rel='stylesheet' type='text/css' href='http://m.lshqa.cn/wenda/style.css' /></head><body> <h1>Calculator</h1> <FORM METHOD='POST' action='Controller'>N1: <input type ='text' name='nr1' value='0'>op: <input type ='text' name='op' value='+'>N2: <input type ='text' name='nr2' value='0'><INPUT TYPE='submit' NAME='actiune' VALUE='Calculate'/> </FORM> <jsp:useBean scope='session'/> <jsp:setProperty name='binOp' property='*'/></body>
servlet的processRequest方法Controller.java放在程序包servlet中：
protected void processRequest(HttpServletRequest request,HttpServletResponse response)throws ServletException,IOException { response.setContentType('text/html;charset=UTF-8'); PrintWriter out = response.getWriter(); HttpSession session = request.getSession(true); BinaryOperation binOp = (BinaryOperation) session.getAttribute('binOp'); try {if (!binOp.isComplete()) { System.out.println(binOp.getNr1() + binOp.getNr2() + binOp.getOp()); response.sendRedirect('index.jsp');} else { out.println('<html>'); out.println('<head>'); out.println('<title>Servlet Controller</title>'); out.println('</head>'); out.println('<body>'); out.println('<h1>Bean in controller ' + binOp.getNr1() + '__' + binOp.getOp() + '__' + binOp.getNr2() + '</h1>'); out.println(binOp.toString()); out.println('</body>'); out.println('</html>');} } finally {out.close(); }}
然后將bean BinaryOperation放入程序包bean中：
package beans;public class BinaryOperation {private String nr1;private String op;private String nr2;public void setNr1(String nr1) { this.nr1 = nr1;}public void setOp(String op) { this.op = op;}public void setNr2(String nr2) { this.nr2 = nr2;}public String getNr1() { return nr1;}public String getOp() { return op;}public String getNr2() { return nr2;}public boolean isComplete() { return !(((nr1 == null) || (nr1.length() == 0)) || ((op == null) || (op.length() == 0)) || ((nr2 == null) || (nr2.length() == 0)));}}
在Apache日志中，我有if語句的下一個(gè)輸出（請(qǐng)參閱servlet-System.out.println（binOp.getNr1（）+binOp.getNr2（）+ binOp.getOp（））;）：nullnullnull
我的錯(cuò)誤在哪里？
標(biāo)簽：
java
上一條：從單擊它的html表行中預(yù)填充表單字段。（所有這些都應(yīng)該在jsp上發(fā)生）下一條：一段時(shí)間不活動(dòng)后，出現(xiàn)“沒有更多數(shù)據(jù)可從套接字讀取”的信息。Weblogic和Oracle DB
相關(guān)文章：
1. python - oslo_config2. python - 如何統(tǒng)計(jì)一份英文 API 開發(fā)文檔（如 javadoc文檔）的詞頻？3. mysql優(yōu)化 - mysql 一張表如果不能確保字段列長度一致，是不是就不需要用到char。4. python - 請(qǐng)問這兩個(gè)地方是為什么呢？5. python - 為什么match匹配出來的結(jié)果是<_sre.SRE_Match object; span=(0, 54), match=’’>6. 請(qǐng)教一個(gè)mysql去重取最新記錄7. javascript - 按鈕鏈接到另一個(gè)網(wǎng)址 怎么通過百度統(tǒng)計(jì)計(jì)算按鈕的點(diǎn)擊數(shù)量8. 人工智能 - python 機(jī)器學(xué)習(xí) 醫(yī)療數(shù)據(jù) 怎么學(xué)9. 大家都用什么工具管理mysql數(shù)據(jù)庫？10. php - 有關(guān)sql語句反向LIKE的處理
<jsp:useBean scope='session'/><jsp:setProperty name='binop' property='*'/>.
這做到了“魔術(shù)”。
解決方法我必須使用Java bean從jsp文件中獲取2個(gè)數(shù)字和一個(gè)運(yùn)算。提交數(shù)字后，將它們從該Java Bean帶到servlet并返回它們的結(jié)果。問題是Javabean字段永遠(yuǎn)不會(huì)用文本框中寫的數(shù)字來完成。所以，我有了index.jsp的主體：
<html><head> <meta http-equiv='Content-Type' content='text/html; charset=UTF-8'> <title>JSP Page</title> <link rel='stylesheet' type='text/css' href='http://m.lshqa.cn/wenda/style.css' /></head><body> <h1>Calculator</h1> <FORM METHOD='POST' action='Controller'>N1: <input type ='text' name='nr1' value='0'>op: <input type ='text' name='op' value='+'>N2: <input type ='text' name='nr2' value='0'><INPUT TYPE='submit' NAME='actiune' VALUE='Calculate'/> </FORM> <jsp:useBean scope='session'/> <jsp:setProperty name='binOp' property='*'/></body>
servlet的processRequest方法Controller.java放在程序包servlet中：
protected void processRequest(HttpServletRequest request,HttpServletResponse response)throws ServletException,IOException { response.setContentType('text/html;charset=UTF-8'); PrintWriter out = response.getWriter(); HttpSession session = request.getSession(true); BinaryOperation binOp = (BinaryOperation) session.getAttribute('binOp'); try {if (!binOp.isComplete()) { System.out.println(binOp.getNr1() + binOp.getNr2() + binOp.getOp()); response.sendRedirect('index.jsp');} else { out.println('<html>'); out.println('<head>'); out.println('<title>Servlet Controller</title>'); out.println('</head>'); out.println('<body>'); out.println('<h1>Bean in controller ' + binOp.getNr1() + '__' + binOp.getOp() + '__' + binOp.getNr2() + '</h1>'); out.println(binOp.toString()); out.println('</body>'); out.println('</html>');} } finally {out.close(); }}
然后將bean BinaryOperation放入程序包bean中：
package beans;public class BinaryOperation {private String nr1;private String op;private String nr2;public void setNr1(String nr1) { this.nr1 = nr1;}public void setOp(String op) { this.op = op;}public void setNr2(String nr2) { this.nr2 = nr2;}public String getNr1() { return nr1;}public String getOp() { return op;}public String getNr2() { return nr2;}public boolean isComplete() { return !(((nr1 == null) || (nr1.length() == 0)) || ((op == null) || (op.length() == 0)) || ((nr2 == null) || (nr2.length() == 0)));}}
在Apache日志中，我有if語句的下一個(gè)輸出（請(qǐng)參閱servlet-System.out.println（binOp.getNr1（）+binOp.getNr2（）+ binOp.getOp（））;）：nullnullnull
我的錯(cuò)誤在哪里？
網(wǎng)公網(wǎng)安備 34170202000408號(hào)-皖I(lǐng)CP備2020019022號(hào)-1 sitemap
Copyright ￠ 2020-2025 Powered by http://m.lshqa.cn V1.8 All Rights Reserved 技術(shù)支持：好吧啦網(wǎng)