java web中如何通过filter 设置全局编码

在这两个包装类基础上，继承HttpServletRequestWrapper ，覆盖需要增强的方法即可。

在Filter中，对request对象进行包装，增强获得参数的方法：

getParameter

getParameterValues

getParameterMap

ServletResponseWrapper 和 HttpServletResponseWrapper 提供了对response 对象包装，继承 HttpServletResponseWrapper ，覆盖需要增强response的方法。

public class EncodingFilter implements Filter {

public void destroy() {

}

public void doFilter(ServletRequest req, ServletResponse resp,

FilterChain chain) throws IOException, ServletException {

// 1.强制转换

HttpServletRequest request = (HttpServletRequest) req;

HttpServletResponse response = (HttpServletResponse) resp;

// 2.操作

HttpServletRequest myrequest = new MyRequest(request); // 增强后的request,解决了编码问题

response.setContentType("text/html;charset=utf-8");

// 3.放行

chain.doFilter(myrequest, response);

public void init(FilterConfig filterConfig) throws ServletException {

// 装饰类

class MyRequest extends HttpServletRequestWrapper {

private HttpServletRequest request;

public MyRequest(HttpServletRequest request) {

super(request);

this.request = request;

// 重写关于获取请求参数的方法.

@Override

public String getParameter(String name) {

Map<String, String[]> map = getParameterMap();

if (name == null) {

return null;

String[] st = map.get(name);

if (st == null || st.length == 0) {

return st[0];

public String[] getParameterValues(String name) {

return st;

private boolean flag = true；

public Map getParameterMap() {

// 1.得到所有请求参数的Map集合

Map<String, String[]> map = request.getParameterMap(); // 有编码问题.

// 2.解决编码问题.

if (flag) {

for (String key : map.keySet()) {

String[] values = map.get(key);

for (int i = 0; i < values.length; i++) {

try {

values[i] = new String(values[i].getBytes("iso8859-1"),

"utf-8");

} catch (UnsupportedEncodingException e) {

e.printStackTrace();

flag = false;

return map;