我们通常读取的都是根据 HTML 中的标签的不同的 NAME 值来获取 Parameter 的，但是，如果有多个标签是相同的 NAME 值呢？比方说 HTML 如下的网页：
1: <form method="post" action="login"> 2: <div>Username:<input class="input" type="text" name="name"/><br/> div> 3: <div>Password:<input class="input" type="text" name="name"/><br/> div> 4: <input type="submit" value="Submit"/> 5: form> .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; }此时我们可以参照如下代码解决问题：
1: String[] values = req.getParameterValues("name"); 2: if (values.length == 1) { 3: if (values[0].length() != 0) { 4: resp.getWriter().println("" + values[0] + ""); 5: } else { 6: resp.getWriter().println("空值"); 7: } 8: } else { 9: for (String s : values) { 10: resp.getWriter().println("" + s + ""); 11: } 12: } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; }也就是调用 getParameterValues("name") 来读取多个值。
此外，我们还可以通过 getParameterMap() 来实现：
1: Map parasMap = req.getParameterMap(); 2: Set > parasSet = parasMap.entrySet(); 3: for (Map.Entry s : parasSet) { 4: String[] values = s.getValue(); 5: for (String val : values) { 6: if (val.length() != 0) { 7: resp.getWriter().println("" + val + "
"); 8: } else { 9: resp.getWriter().println("空值
"); 10: } 11: } 12: }