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From: blog.csdn.net/Muscleheng/article/details/80067772
Problems encountered:
The foreground submits the parameters to the background through a message or using a form or ajax. If our request parameters are encrypted, then we need to decrypt each method in the controller. If there are too many methods, it will be too cumbersome.
Design:
Using a filter, take out all the parameters in the HttpServletRequest in a Filter, filter them separately, and then put them back into the HttpServletRequest, right?
After testing, it is found that it is not feasible, because HttpServletRequest only provides getParameter, but not setParameter; therefore, we can only write a HttpServletRequest method to inherit HttpServletRequestWrapper, then override the method inside, and add our own setParameters method, so that we can You can do whatever you want, and finally call the methods of this class in the filter to process the parameters (get, modify, store, etc.).
solution:
Before the request parameters reach the controller, decryption is performed in the filter; in this way, through simple filter processing, all requests that need to be processed are decrypted in the filter, which is equivalent to realizing automatic processing.
Here we explain two different request methods:
Ordinary form, ajax request;
A message request in json format. (Three steps to get it)
1. Ordinary form, ajax request;
Step 1: Create a new class
This class inherits from HttpServletRequestWrapper
import java.io.IOException;
import java.util.HashMap;
import java.util.Map;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletRequestWrapper;
/**
* 重写 HttpServletRequestWrapper
* 处理表单、ajax请求
* @author zhaoheng
*
*/
public class MyHttpServletRequestWrapper1 extends HttpServletRequestWrapper{
// 用于存储请求参数
private Map<String , String[]> params = new HashMap<String, String[]>();
// 构造方法
public MyHttpServletRequestWrapper1(HttpServletRequest request) throws IOException {
super(request);
// 把请求参数添加到我们自己的map当中
this.params.putAll(request.getParameterMap());
}
/**
* 添加参数到map中
* @param extraParams
*/
public void setParameterMap(Map<String, Object> extraParams) {
for (Map.Entry<String, Object> entry : extraParams.entrySet()) {
setParameter(entry.getKey(), entry.getValue());
}
}
/**
* 添加参数到map中
* @param name
* @param value
*/
public void setParameter(String name, Object value) {
if (value != null) {
System.out.println(value);
if (value instanceof String[]) {
params.put(name, (String[]) value);
} else if (value instanceof String) {
params.put(name, new String[]{(String) value});
} else {
params.put(name, new String[]{String.valueOf(value)});
}
}
}
/**
* 重写getParameter，代表参数从当前类中的map获取
* @param name
* @return
*/
@Override
public String getParameter(String name) {
String[]values = params.get(name);
if(values == null || values.length == 0) {
return null;
}
return values[0];
}
/**
* 重写getParameterValues方法，从当前类的 map中取值
* @param name
* @return
*/
@Override
public String[] getParameterValues(String name) {
return params.get(name);
}
}By creating this class, we can add the parameters we processed to the request object.
Step 2: Create a filter by implementing the filter interface
package com.zhh.filter;
import java.io.IOException;
import java.util.Arrays;
import java.util.List;
import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import org.apache.log4j.Logger;
import com.zhh.util.request.MyHttpServletRequestWrapper1;
/**
* 参数处理验过滤器（针对ajax、表单等请求） 1.获取请求参数；2.对获取到的请求参数进行处理（解密、字符串替、请求参数分类截取等等）；3.把处理后的参数放回到请求列表里面
*
* @author zhaoheng
*
*/
public class ValidatorFilter1 implements Filter {
private static final Logger log = Logger.getLogger(ValidatorFilter1.class);
/**
* 需要过滤的地址
*/
private static List<String> urlList = Arrays.asList("/pastOrder/filterCsF");
/**
* 是否不需要过滤
*
* @param requestUrl
* 请求的url
* @return
*/
public boolean isPast(String requestUrl) {
for (String url : urlList) {
if (requestUrl.equals(url)) {
return true;
}
}
return false;
}
@Override
public void destroy() {
}
@SuppressWarnings("unchecked")
@Override
public void doFilter(ServletRequest request, ServletResponse response,
FilterChain chain) throws IOException, ServletException {
log.info("过滤器2执行开始");
String url = ((HttpServletRequest) request).getRequestURI().substring(((HttpServletRequest)request).getContextPath().length());
//通过地址对特定的请求进行处理，如果不需要可以不用，如果不用，就会对使用的请求进行过滤
if (isPast(url)) {
MyHttpServletRequestWrapper1 requestWrapper1 = new MyHttpServletRequestWrapper1(
(HttpServletRequest) request);
// 1.获取需要处理的参数
String email = requestWrapper1.getParameter("email");
// 2.把处理后的参数放回去（这里是大小转小写处理）
requestWrapper1.setParameter("email", email.toLowerCase());
// 3.放行，把我们的requestWrapper1放到方法当中
chain.doFilter(requestWrapper1, response);
} else {
chain.doFilter(request, response);
}
}
@Override
public void init(FilterConfig arg0) throws ServletException {
}
}Step 3: Configure the filter
Method 1. Simple configuration in the web.xml file (general project)
Register our filter in this file
<!-- 配置过滤器 -->
<filter>
<filter-name>ValidatorFilter1</filter-name>
<!-- 我们写的过滤的地址 -->
<filter-class>com.zhh.filter.ValidatorFilter1</filter-class>
</filter>
<filter-mapping>
<filter-name>ValidatorFilter1</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>Method 2, configuration of springboot project
Create a new configuration class, add the @Configuration annotation, and add the @Bean annotation to the method header
@Configuration
public class WebFileterConfig {
/**
* 配置过滤器
* order属性:控制过滤器加载顺序：数字越小，加载越早
* @return
*/
@Bean
public FilterRegistrationBean ValidatorFilterRegistration() {
//新建过滤器注册类
FilterRegistrationBean registration = new FilterRegistrationBean();
// 添加我们写好的过滤器
registration.setFilter( new ValidatorFilter1());
// 设置过滤器的URL模式
registration.addUrlPatterns("/*");
registration.setOrder(Integer.MAX_VALUE-10);
return registration;
}
}The controller receives the parameter code:
/**
* 过滤方法测试
*/
@RequestMapping("/filterCsF2")
public void filterCs22(String email,String userName){
System.out.println("处理后的参数："+userName+" "+email);
}Request sample code:
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>请求demo</title>
</head>
<body>
<form id="userForm" action="#" method="post">
username：<input type="text" id ="userName" name="userName" value="21088888"/><br/><br>
email：<input type="text" id ="email" name="email" value="[email protected]"/><br/><br/>
age：<input type="text" id ="age" name="age" value="18"/><br/><br/>
<input type="reset" value="重置"/>
<input type="button" id ="sub" value="提交">
</form>
</body>
<script src="jquery.min.js"></script>
<script type="text/javascript">
$("#sub").click(
function(){
var userName = $("#userName").val();
var email = $("#email").val();
var age = $("#age").val();
$.ajax({
type : "POST",
url:'http://127.0.0.1:8080/merchant_wap/pastOrder/filterCsF2',
dataType : "json",
data : {
"userName":userName,
"age":age,
"email":email
},
success : function(data) {
alert("33");
},
error : function(data) {
alert("cccc"+data.email);
}
});
}
);
</script>
</html>process result:
处理后的参数：21088888 [email protected]As can be seen from the results, we successfully converted the requested email from uppercase to lowercase through the filter.
2. Message request in json format;
Step 1: Create a new class
This class inherits from HttpServletRequestWrapper
package com.zhh.util.request;
import java.io.BufferedReader;
import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import javax.servlet.ServletInputStream;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletRequestWrapper;
import jodd.io.StreamUtil;
/**
* 重写 HttpServletRequestWrapper
* 处理json报文请求
* @author zhaoheng
*
*/
public class MyHttpServletRequestWrapper extends HttpServletRequestWrapper{
private byte[] body; //用于保存读取body中数据
public MyHttpServletRequestWrapper(HttpServletRequest request) throws IOException {
super(request);
//读取请求的数据保存到本类当中
body = StreamUtil.readBytes(request.getReader(), "UTF-8");
}
//覆盖（重写）父类的方法
@Override
public BufferedReader getReader() throws IOException {
return new BufferedReader(new InputStreamReader(getInputStream()));
}
//覆盖（重写）父类的方法
@Override
public ServletInputStream getInputStream() throws IOException {
final ByteArrayInputStream bais = new ByteArrayInputStream(body);
return new ServletInputStream() {
@Override
public int read() throws IOException {
return bais.read();
}
};
}
/**
* 获取body中的数据
* @return
*/
public byte[] getBody() {
return body;
}
/**
* 把处理后的参数放到body里面
* @param body
*/
public void setBody(byte[] body) {
this.body = body;
}
}By creating this class, we can add the parameters we processed to the request object.
Step 2: Create a filter by implementing the filter interface
package com.zhh.filter;
import java.io.BufferedReader;
import java.io.IOException;
import java.util.Arrays;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import org.apache.log4j.Logger;
import com.alibaba.fastjson.JSON;
import com.alibaba.fastjson.JSONObject;
import com.zhh.util.request.MyHttpServletRequestWrapper;
/**
* 参数校验过滤器（针对json报文请求） 1.获取请求参数；2.对获取到的请求参数进行处理（解密、字符串替、请求参数分类截取等等）；3.把处理后的参数放回到请求列表里面
*
* @author zhaoheng
*
*/
public class ValidatorFilter implements Filter {
private static final Logger log = Logger.getLogger(ValidatorFilter.class);
/**
* 需要过滤的地址
*/
private static List<String> urlList = Arrays.asList("/pastOrder/filterCs");
/**
* 是否需要过滤
*
* @param requestUrl
* 请求的url
* @return
*/
public boolean isPast(String requestUrl) {
for (String url : urlList) {
if (requestUrl.equals(url)) {
return true;
}
}
return false;
}
@Override
public void destroy() {
log.info("过滤器执行结束");
}
@SuppressWarnings("unchecked")
@Override
public void doFilter(ServletRequest request, ServletResponse response,
FilterChain chain) throws IOException, ServletException {
log.info("过滤器1执行开始");
String url0 = ((HttpServletRequest) request).getRequestURI();
String url1 = ((HttpServletRequest) request).getContextPath();
System.out.println("完整地址："+url0);
System.out.println("返回当前页面所在的应用的名字："+url1);
System.out.println("返回当前页面所在的应用的名字长度："+url1.length());
// 获取请求地址
String url = ((HttpServletRequest) request).getRequestURI().substring(((HttpServletRequest)request).getContextPath().length());
System.out.println("截取后的地址："+url);
if (isPast(url)) {
//处理json报文请求
MyHttpServletRequestWrapper requestWrapper = new MyHttpServletRequestWrapper(
(HttpServletRequest) request);
// 读取请求内容
BufferedReader br;
br = requestWrapper.getReader();
String line = null;
StringBuilder sb = new StringBuilder();
while ((line = br.readLine()) != null) {
sb.append(line);
}
// 将json字符串转换为json对象
JSONObject jsonObject = JSONObject.parseObject(sb.toString());
Map<String, Object> map = new HashMap<String, Object>();
// 把json对象转换为Map集合
map = JSON.toJavaObject(jsonObject, Map.class);
for (Entry<String, Object> entry : map.entrySet()) {
// 把邮箱地址转换为小写
if (entry.getKey().equals("email")) {
map.put(entry.getKey(), entry.getValue().toString()
.toLowerCase());
}
}
// 把参数转换之后放到我们的body里面
String json = JSON.toJSONString(map);
requestWrapper.setBody(json.getBytes("UTF-8"));
// 放行
chain.doFilter(requestWrapper, response);
} else {
chain.doFilter(request, response);
}
}
@Override
public void init(FilterConfig arg0) throws ServletException {
}
}third step:
Method 1. Simple configuration in the web.xml file
Register our filter in this file
<!-- 配置过滤器 -->
<filter>
<filter-name>ValidatorFilter</filter-name>
<!-- 我们写的过滤的地址 -->
<filter-class>com.zhh.filter.ValidatorFilter</filter-class>
</filter>
<filter-mapping>
<filter-name>ValidatorFilter</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>Method 2, configuration of springboot project
Create a new configuration class, add the @Configuration annotation, and add the @Bean annotation to the method header
@Configuration
public class WebFileterConfig {
/**
* 配置过滤器
* order属性:控制过滤器加载顺序：数字越小，加载越早
* @return
*/
@Bean
public FilterRegistrationBean ValidatorFilterRegistration() {
//新建过滤器注册类
FilterRegistrationBean registration = new FilterRegistrationBean();
// 添加我们写好的过滤器
registration.setFilter( new ValidatorFilter());
// 设置过滤器的URL模式
registration.addUrlPatterns("/*");
registration.setOrder(Integer.MAX_VALUE-10);
return registration;
}
}The controller receives the parameter code:
/**
* 过滤方法测试
* @RequestBody User user 该注解用于接收json请求的参数
* @return
*/
@ResponseBody
@RequestMapping(value = "/filterCs")
public User filterCs(@RequestBody User user){
System.out.println(user.toString());
return user;
}Request message example:
I am using the postman tool here for json parameter requests
{
"email": "[email protected]",
"userName":"20181100",
"age":"18"
}Return result:
{
"email": "[email protected]",
"userName":"20181100",
"age":"18"
}With this filter, the email is converted from lowercase successfully.
Through the above operations, we have successfully created a filter.
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