当我们通过一个表单验证来连接数据库时,最关键的就是要确保浏览器的resquest端和服务器的response端能够统一编码,这样请求和返回的信息才能够正确,否则就会出现乱码问题。
如:
当编码不统一时返回信息:
统一编码后:
当然这样的问题还会出现在resquest端,当我们的resquest和response端编码不统一时就会出现如上的编码错误。
如:通过浏览器提交请求,通过resquest的相关方法获取到请求值之后输出结果如图。
在服务端输出:
统一编码后输出:
好了现在先来看关于response应答时的乱码问题的处理:
例如通过以不同的方式输出统一个”上海“ 字样时会有不同的结果,借此我们来解决所遇到的乱码问题。
问题一:
MyServlet.java
package net.csdn.servlet;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class MyServlet extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
testEncoding1(response);
}
方法一:
public void testEncoding1(ServletResponse response) throws IOException{
String content = "上海";
OutputStream os = response.getOutputStream();
//这里默认的写入到response相应头中的编码方式为GB2312这正好要与浏览器默认编码方式相同
//所以可以正常解析
os.write(content.getBytes());
}
但我们如果指定response的输入编码集时:
方法二:
public void testEncoding2(ServletResponse response) throws IOException{
String content = "上海";
OutputStream os = response.getOutputStream();
//这里由于指定了的写入到response相应头中的编码方式为utf-8而浏览器默认编码方却仍是GB2312
//所以解析出现乱码
os.write(content.getBytes("utf-8"));
}
解决方式:
public void testEncoding3(ServletResponse response) throws IOException{
String content = "上海";
OutputStream os = response.getOutputStream();
//这里由于指定了的写入到response相应头中的编码方式为utf-8而浏览器默认编码方却仍是GB2312
//所以解析出现乱码
os.write(content.getBytes("utf-8"));
//解决方法:为响应信息设置响应头告诉浏览器以utf-8的方式来解析编码或者在浏览器一端将编码方式
//改为utf-8也可解决该问题
response.setContentType("text/html;charset = utf-8");
}
方法三:
public void testEncoding4(HttpServletResponse response) throws IOException{
String content = "上海";
// response.setContentType("text/html;charset = utf-8");
OutputStream os = response.getOutputStream();
//这里由于指定了的写入到response相应头中的编码方式为utf-8而浏览器默认编码方却仍是GB2312
//所以解析出现乱码
os.write(content.getBytes("utf-8"));
}
解决:
public void testEncoding4(HttpServletResponse response) throws IOException{
String content = "上海";
OutputStream os = response.getOutputStream();
//这里由于指定了的写入到response相应头中的编码方式为utf-8而浏览器默认编码方却仍是GB2312
//所以解析出现乱码
os.write(content.getBytes("utf-8"));
//解决方法:为响应信息设置响应头告诉浏览器以utf-8的方式来解析编码或者在浏览器一端将编码方式
//改为utf-8也可解决该问题
// response.setContentType("text/html;charset = utf-8");
//以另一种方式设置响应头告知浏览器的解码方式
response.setHeader("Content-Type", "text/html;charset = utf-8");
}
方法四及解决:
public void testEncoding5(ServletResponse response) throws IOException{
String content = "上海";
OutputStream os = response.getOutputStream();
os.write(content.getBytes("utf-8"));
//不是发送响应头而是向浏览器输出一段标签来告知浏览器按照相应的utf-8来解析
os.write("".getBytes());
}
方法五及解决:
public void testEncoding6(ServletResponse response) throws IOException{
String content = "上海";
//使用的默认编码集是iso8859-1而浏览器的编码却是utf-8故出现乱码问题
PrintWriter pw = response.getWriter();
pw.println(content);
}
同样会出现乱码
解决:
public void testEncoding6(ServletResponse response) throws IOException{
String content = "上海";
//解决方式同上:
//设置响应头的编码方式
response.setCharacterEncoding("UTF-8");
//通过响应头告诉浏览器正确的解码方式
response.setContentType("text/html;charset = UTF-8");
//使用的默认编码集是iso8859-1而浏览器的编码却是utf-8故出现乱码问题
PrintWriter pw = response.getWriter();
pw.println(content);
}
public void testEncoding7(ServletResponse response) throws IOException{
int content = 14;
//使用的默认编码集是iso8859-1而浏览器的编码却是utf-8故出现乱码问题
PrintWriter pw = response.getWriter();
pw.write(content);
}
解决:
public void testEncoding8(ServletResponse response) throws IOException{
int content = 14;
//解决方式同上:
//设置响应头的编码方式
response.setCharacterEncoding("UTF-8");
//通过响应头告诉浏览器正确的解码方式
response.setContentType("text/html;charset = UTF-8");
//使用的默认编码集是iso8859-1而浏览器的编码却是utf-8故出现乱码问题
PrintWriter pw = response.getWriter();
pw.println(content);
}
关于request:
问题:
UserServlet.java
package com.user.servlet;
import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import com.userbean.User;
import com.userdao.UserDao;
import com.userimpl.UserImpl;
public class UserServlet extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
String username = request.getParameter("username");
String password = request.getParameter("password");
System.out.println(username);
System.out.println(password);
UserDao ud = new UserImpl();
boolean b = ud.findUser(username, password);
if(b == false){
response.setContentType("text/html;charset=UTF-8 ");
response.getWriter().write("用户名或密码有误,请重新确认输入!");
}else{
response.setContentType("text/html;charset=UTF-8 ");
response.getWriter().write("登陆成功!");
}
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doGet(request, response);
}
}
如图:
解决后:
package com.user.servlet;
import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import com.userbean.User;
import com.userdao.UserDao;
import com.userimpl.UserImpl;
public class UserServlet extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
//为request指定编码
request.setCharacterEncoding("UTF-8");
String username = request.getParameter("username");
String password = request.getParameter("password");
System.out.println(username);
System.out.println(password);
UserDao ud = new UserImpl();
boolean b = ud.findUser(username, password);
if(b == false){
response.setContentType("text/html;charset=UTF-8 ");
response.getWriter().write("用户名或密码有误,请重新确认输入!");
}else{
response.setContentType("text/html;charset=UTF-8 ");
response.getWriter().write("登陆成功!");
}
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doGet(request, response);
}
}
好了,现在你已经知道了如何去处理resquest和response的相关编码问题了,赶快自己试一试吧!