中文亂碼
發生中文亂碼的情況主要有三種:
1.表單form
(1)post
(2)get
2.超鏈接
< a href=”http://baidu.com?name=百度”>測試< /a>
3.sendRedirect()發生亂碼
response.sendRedirect(“servlet地址?username=”君莫笑”“);
值得注意的是：亂碼分爲接收方和傳送方。服務器(Tomcat)先接受，然後傳送給瀏覽器
通過實例來解決：
簡單的用戶登錄系統來完成。
先建一張表單，有用戶名和密碼。登陸後會把出現登陸成功字樣，而且會顯示登錄名。
table.html
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<body>
<h1>用戶登錄</h1>
<form action='/UserLoginOne/LoginClServlet' method='post'>
用戶名:<input type='text' name='username'/> <br/>
密 碼:<input type='password' name='password'/> <br/>
<input type='submit' value='登錄'/> <br/>
</form>
</body>
</html>
密碼驗證：LoginClServlet.java
public class LoginClServlet extends HttpServlet {
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
response.setContentType("text/html");
PrintWriter out = response.getWriter();
request.setCharacterEncoding("utf-8");
//接受用戶提交的用戶名和密碼
String username = request.getParameter("username");
String password = request.getParameter("password");
//檢驗
if("123".equals(password)){
response.sendRedirect("/UserLoginOne/MainFrame?uname="+username);
}else{
response.sendRedirect("/UserLoginOne/table.html");
}
}
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
this.doGet(request, response);
}
}
顯示頁面：MainFrame.java
public class MainFrame extends HttpServlet {
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
response.setContentType("text/html");
request.setCharacterEncoding("utf-8");
String name =request.getParameter("uname");
PrintWriter out = response.getWriter();
out.println("<h1>登錄成功Welcome</h1>\n\n\n\n");
out.println("username = "+name);
}
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
this.doGet(request, response);
}
}
試驗：
呵呵。。。不爭氣的東西登錄二字就亂碼了。。。不要慌
response.setContentType("text/html");
原因主要是沒有在這上面申明字符編碼，先改爲：
response.setContentType("text/html;charset=utf-8");
//把eclipse的編碼改爲utf-8,默認是GBK
成功了。。
重點：不要把;寫成，。本人就因爲這個找了一晚上加一早上的錯誤。。。重新敲了一遍才發現。。*
不過用戶名是中文時就亂碼了。。。
1.表單——post
先不使用sendRedirect()方法，接收到數據後直接從服務器和瀏覽器打印
LoginClServlet.java
public class LoginClServlet extends HttpServlet {
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
response.setContentType("text/html");
PrintWriter out = response.getWriter();
//接受用戶提交的用戶名和密碼
String username = request.getParameter("username");
String password = request.getParameter("password");
//檢驗
if("123".equals(password)){
System.out.println("username = "+username);
out.println("username = "+username);
//response.sendRedirect("/UserLoginOne/MainFrame?uname="+username);
}else{
response.sendRedirect("/UserLoginOne/table.html");
}
}
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
this.doGet(request, response);
}
}
結果
LoginClServlet.java 改爲：
public class LoginClServlet extends HttpServlet {
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
response.setContentType("text/html;charset=utf-8");
PrintWriter out = response.getWriter();
request.setCharacterEncoding("utf-8");
//接受用戶提交的用戶名和密碼
String username = request.getParameter("username");
String password = request.getParameter("password");
//檢驗
if("123".equals(password)){
System.out.println("username = "+username);
out.println("username = "+username);
//response.sendRedirect("/UserLoginOne/MainFrame?uname="+username);
}else{
response.sendRedirect("/UserLoginOne/table.html");
}
}
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
this.doGet(request, response);
}
}
這樣服務器和瀏覽器都默認以utf-8編碼顯示，結果：
2.表單——get
把table 改爲
直接運行的話肯定還是亂碼的
LoginClServlet.java
public class LoginClServlet extends HttpServlet {
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
response.setContentType("text/html;charset=utf-8");
PrintWriter out = response.getWriter();
//接受用戶提交的用戶名和密碼
String username = request.getParameter("username");
String password = request.getParameter("password");
//檢驗
if("123".equals(password)){
//服務器默認編碼是"iso-8859-1"，這樣就是把編碼改爲utf-8
String uname = new String(username.getBytes("iso-8859-1"),"utf-8");
System.out.println("username = "+uname);
out.println("username = "+uname);
//response.sendRedirect("/UserLoginOne/MainFrame?uname="+username);
}else{
response.sendRedirect("/UserLoginOne/table.html");
}
}
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
this.doGet(request, response);
}
}
結果
當然自己乾脆寫個工具類
MyTools.java
package Tools;
public class MyTools {
public static String GetNewString(String str){
String newstring ="";
try{
newstring = new String(str.getBytes("iso-8859-1"),"utf-8");
}catch(Exception e){
e.printStackTrace();
}
return newstring;
}
}
LoginClServlet.java
import Tools.MyTools;
public class LoginClServlet extends HttpServlet {
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
response.setContentType("text/html;charset=utf-8");
PrintWriter out = response.getWriter();
//接受用戶提交的用戶名和密碼
String username = request.getParameter("username");
String password = request.getParameter("password");
//檢驗
if("123".equals(password)){
String uname = MyTools.GetNewString(username);
System.out.println("username = "+uname);
out.println("username = "+uname);
//response.sendRedirect("/UserLoginOne/MainFrame?uname="+username);
}else{
response.sendRedirect("/UserLoginOne/table.html");
}
}
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
this.doGet(request, response);
}
}
3.超鏈接
和get原理一樣，直接用工具類就行了
4.sendRedirect()方法
根據table.html的傳送方式看；我的是get.
LoginClServlet.java
public class LoginClServlet extends HttpServlet {
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
response.setContentType("text/html;charset=utf-8");
PrintWriter out = response.getWriter();
//接受用戶提交的用戶名和密碼
String username = request.getParameter("username");
String password = request.getParameter("password");
//檢驗
if("123".equals(password)){
response.sendRedirect("/UserLoginOne/MainFrame?uname="+username);
}else{
response.sendRedirect("/UserLoginOne/table.html");
}
}
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
this.doGet(request, response);
}
}
MainFrame.java
public class MainFrame extends HttpServlet {
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
response.setContentType("text/html;charset=utf-8");
PrintWriter out = response.getWriter();
out.println("<h1>登錄成功Welcome</h1>\n\n\n\n");
String name =MyTools.GetNewString(request.getParameter("uname"));
System.out.println("username 2= "+name);
out.println("uname 1 = "+name);
}
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
this.doGet(request, response);
}
結果：
亂碼情況基本就這幾種。
*補充：*
下載文件時，提示框可能是亂碼：
解決方案：
String temp = java.net.URLEncoder.encode("***(文件名)"，"utf-8");
response.setHeader("Content-Disposition","attachment;filename"+temp);