java 乱码解决办法

1、一般的jsp页面显示乱码
<%@ page contentType="text/html; charset=UTF-8"%>

<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">

 

2、表单提交中文时出现乱码

jsp提交英文字符能正确显示，而提交中文时就会出现乱码。
原因：浏览器默认使用UTF-8编码方式来发送请求，而UTF- 8和GB2312编码方式表示字符时不一样，
这样就出现了不能识别字符

解决：再jsp页面设定 <%request.seCharacterEncoding("UTF-8");%>对请求进行统一编码
为了避免每页都要写request.setCharacterEncoding("UTF-8")，

建议使用过滤器对所有jsp进行编码处理，

过滤器——.java文件：
public class SetCharacterEncodingFilter implements Filter{

/*过滤器,解决中文乱码问题*/
protected String encoding = "UTF-8";
protected FilterConfig filterConfig = null;
protected boolean ignore = true;
public void destroy() {
// TODO Auto-generated method stub
this.encoding = null;
this.filterConfig = null;

}

public void doFilter(ServletRequest request, ServletResponse response,
FilterChain chain) throws IOException, ServletException {
// TODO Auto-generated method stub
try {
// Conditionally select and set the character encoding to be used
if (ignore || (request.getCharacterEncoding() == null)) {
String encoding = selectEncoding(request);
if (encoding != null)
request.setCharacterEncoding(encoding);
}

// Pass control on to the next filter
chain.doFilter(request, response);
} catch (IOException e) {

throw e;
} catch (ServletException e) {

throw e;
}

}

public void init(FilterConfig filterConfig) throws ServletException {
// TODO Auto-generated method stub
this.filterConfig = filterConfig;
this.encoding = filterConfig.getInitParameter("encoding");
String value = filterConfig.getInitParameter("ignore");
if (value == null)
this.ignore = true;
else if (value.equalsIgnoreCase("true"))
this.ignore = true;
else if (value.equalsIgnoreCase("yes"))
this.ignore = true;
else
this.ignore = false;

}
protected String selectEncoding(ServletRequest request) {
return (this.encoding);
}

}
过滤器——web.xml文件中的配置：
<filter>
<filter-name>Set Character Encoding</filter-name>
<filter-class>
net.better_best.www.utils.SetCharacterEncodingFilter
</filter-class>
<init-param>
<param-name>encoding</param-name>
<param-value>UTF-8</param-value>
</init-param>
</filter>
<filter-mapping>
<filter-name>Set Character Encoding</filter-name>
<servlet-name>action</servlet-name>
</filter-mapping>

 

3、数据库连接出现乱码
只要涉及中文的地方全部是乱码，解决办法：在数据库的数据库URL中加上
String Url="jdbc:mysql://localhost/digitgulf?user=root&password=root&useUnicode=true&characterEncoding=UTF-8";
　　并在页面中使用如下代码：
　　response.setContentType("text/html;charset=UTF-8");
　　request.setCharacterEncoding("UTF-8");

 

4、URL传值乱码问题解决，这个也是最麻烦的事情啦

如果是Tomcat的话，需要在server.xml里面的connector里面务必设置如下参数：
<Connector port="8080"

maxThreads="150" minSpareThreads="25" maxSpareThreads="75"

enableLookups="false" redirectPort="8443" acceptCount="100"

debug="0" connectionTimeout="20000" useBodyEncodingForURI="true"

disableUploadTimeout="true" URIEncoding=”UTF-8”/>

设定URIEncoding=”UTF-8” useBodyEncodingForURI="true"

但是这样还是会出问题的，比如URL传递参数是奇数或者偶数时...

String techName= request.getParameter("selTechnicalArticlesTitle").trim();
//URL 传递值时用Encoder进行编码
java.net.URLEncoder.encode(techName, "UTF-8")
也可以在JSP页面：

       encodeURI(encodeURI(tname));

//对页面传来的字符进行解码:
java.net.URLDecoder.decode(techName,"UTF-8");

//多个参数传递

techType.do?techid=1&techName=中国&name=汉字

techid,techName,name是参数名

与你在Action当中用request.getParameter("techName") 一定要相同;

你传的时候名称与你页面查询条件输入框的名称一定要对应,因为Action当中取的是页面输入框的名称;

明白?