springMVC-乱码问题

1 编写一个出现乱码的情况

1.1 编写一个提交form表单的测试页面

 <%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>Title</title>
</head>
<body>
<form action="${pageContext.request.contextPath}/e/t" method="get">
    <input type="text" name="name">
    <input type="submit">
</form>
</body>
</html>

1.2 在后台编写对应的处理类

 @Controller
public class Encoding {
    @RequestMapping("/e/t")
    public String test(Model model,String name){
        System.out.println(name);
        model.addAttribute("msg",name);
        return "test";
    }
}

1.3 启动tomcat测试

访问测试页面并且提交一个中文参数

1.4 执行结果

2 解决乱码

2.1 尝试使用spring自带的乱码过滤器

2.1.1 需要依赖支持

 <dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-webmvc</artifactId>
    <version>5.2.0.RELEASE</version>
</dependency>

2.1.2 配置web.xml文件

 <!--配置springmvc的编码过滤器-->
<filter>
    <filter-name>encoding</filter-name>
    <filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class>
    <init-param>
        <param-name>encoding</param-name>
        <param-value>utf-8</param-value>
    </init-param>
</filter>
<filter-mapping>
    <filter-name>encoding</filter-name>
    <url-pattern>/*</url-pattern>
</filter-mapping>

2.2 如果无效,尝试检查Tomcat配置文件

apache-tomcat-9.0.55\conf\server.xml

 <Connector URIEncoding="utf-8" port="8080" protocol="HTTP/1.1"
                       connectionTimeout="20000"
                       redirectPort="8443" />

2.3 如果还无效,就自定义一个过滤器

2.3.1 编写过滤器

 package com.lv.filter;
 
import javax.servlet.*;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletRequestWrapper;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.nio.charset.StandardCharsets;
import java.util.Map;
 
/**
 * 解决get和post请求 全部乱码的过滤器
 */
public class GenericEncodingFilter implements Filter {
    @Override
    public void destroy() {
    }
    @Override
    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
        //处理response的字符编码
        HttpServletResponse myResponse=(HttpServletResponse) response;
        myResponse.setContentType("text/html;charset=UTF-8");
 
        // 转型为与协议相关对象
        HttpServletRequest httpServletRequest = (HttpServletRequest) request;
        // 对request包装增强
        HttpServletRequest myRequest = new MyRequest(httpServletRequest);
        chain.doFilter(myRequest, response);
    }
    @Override
    public void init(FilterConfig filterConfig) throws ServletException {
    }
 
}
//自定义request对象，HttpServletRequest的包装类
class MyRequest extends HttpServletRequestWrapper {
    private final HttpServletRequest request;
    //是否编码的标记
    private boolean hasEncode;
    //定义一个可以传入HttpServletRequest对象的构造函数，以便对其进行装饰
    public MyRequest(HttpServletRequest request) {
        super(request);// super必须写
        this.request = request;
    }
    // 对需要增强方法 进行覆盖
    @Override
    public Map getParameterMap() {
        // 先获得请求方式
        String method = request.getMethod();
        if (method.equalsIgnoreCase("post")) {
            // post请求
            try {
                // 处理post乱码
                request.setCharacterEncoding("utf-8");
                return request.getParameterMap();
            } catch (UnsupportedEncodingException e) {
                e.printStackTrace();
            }
        } else if (method.equalsIgnoreCase("get")) {
            // get请求
            Map<String, String[]> parameterMap = request.getParameterMap();
            if (!hasEncode) { // 确保get手动编码逻辑只运行一次
                for (String parameterName : parameterMap.keySet()) {
                    String[] values = parameterMap.get(parameterName);
                    if (values != null) {
                        for (int i = 0; i < values.length; i++) {
                            // 处理get乱码
                            values[i] = new String(values[i]
                                    .getBytes(StandardCharsets.ISO_8859_1), StandardCharsets.UTF_8);
                        }
                    }
                }
                hasEncode = true;
            }
            return parameterMap;
        }
        return super.getParameterMap();
    }
    //取一个值
    @Override
    public String getParameter(String name) {
        Map<String, String[]> parameterMap = getParameterMap();
        String[] values = parameterMap.get(name);
        if (values == null) {
            return null;
        }
        return values[0]; // 取回参数的第一个值
    }
    //取所有值
    @Override
    public String[] getParameterValues(String name) {
        Map<String, String[]> parameterMap = getParameterMap();
        return parameterMap.get(name);
    }
}

2.3.2 配置web.xml文件

 <!--自定义编码过滤器-->
<filter>
    <filter-name>encoding</filter-name>
    <filter-class>com.lv.filter.GenericEncodingFilter</filter-class>
</filter>
<filter-mapping>
    <filter-name>encoding</filter-name>
    <url-pattern>/*</url-pattern>
</filter-mapping>

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springMVC-乱码问题

公告

随笔分类

随笔档案

	<%@ page contentType="text/html;charset=UTF-8" language="java" %>
	<html>
	<head>
	<title>Title</title>
	</head>
	<body>
	<form action="${pageContext.request.contextPath}/e/t" method="get">
	<input type="text" name="name">
	<input type="submit">
	</form>
	</body>
	</html>

	@Controller
	public class Encoding {
	@RequestMapping("/e/t")
	public String test(Model model,String name){
	System.out.println(name);
	model.addAttribute("msg",name);
	return "test";
	}
	}

	<dependency>
	<groupId>org.springframework</groupId>
	<artifactId>spring-webmvc</artifactId>
	<version>5.2.0.RELEASE</version>
	</dependency>

	<!--配置springmvc的编码过滤器-->
	<filter>
	<filter-name>encoding</filter-name>
	<filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class>
	<init-param>
	<param-name>encoding</param-name>
	<param-value>utf-8</param-value>
	</init-param>
	</filter>
	<filter-mapping>
	<filter-name>encoding</filter-name>
	<url-pattern>/*</url-pattern>
	</filter-mapping>

	<Connector URIEncoding="utf-8" port="8080" protocol="HTTP/1.1"
	connectionTimeout="20000"
	redirectPort="8443" />

	package com.lv.filter;

	import javax.servlet.*;
	import javax.servlet.http.HttpServletRequest;
	import javax.servlet.http.HttpServletRequestWrapper;
	import javax.servlet.http.HttpServletResponse;
	import java.io.IOException;
	import java.io.UnsupportedEncodingException;
	import java.nio.charset.StandardCharsets;
	import java.util.Map;

	/**
	* 解决get和post请求全部乱码的过滤器
	*/
	public class GenericEncodingFilter implements Filter {
	@Override
	public void destroy() {
	}
	@Override
	public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
	//处理response的字符编码
	HttpServletResponse myResponse=(HttpServletResponse) response;
	myResponse.setContentType("text/html;charset=UTF-8");

	// 转型为与协议相关对象
	HttpServletRequest httpServletRequest = (HttpServletRequest) request;
	// 对request包装增强
	HttpServletRequest myRequest = new MyRequest(httpServletRequest);
	chain.doFilter(myRequest, response);
	}
	@Override
	public void init(FilterConfig filterConfig) throws ServletException {
	}

	}
	//自定义request对象，HttpServletRequest的包装类
	class MyRequest extends HttpServletRequestWrapper {
	private final HttpServletRequest request;
	//是否编码的标记
	private boolean hasEncode;
	//定义一个可以传入HttpServletRequest对象的构造函数，以便对其进行装饰
	public MyRequest(HttpServletRequest request) {
	super(request);// super必须写
	this.request = request;
	}
	// 对需要增强方法进行覆盖
	@Override
	public Map getParameterMap() {
	// 先获得请求方式
	String method = request.getMethod();
	if (method.equalsIgnoreCase("post")) {
	// post请求
	try {
	// 处理post乱码
	request.setCharacterEncoding("utf-8");
	return request.getParameterMap();
	} catch (UnsupportedEncodingException e) {
	e.printStackTrace();
	}
	} else if (method.equalsIgnoreCase("get")) {
	// get请求
	Map<String, String[]> parameterMap = request.getParameterMap();
	if (!hasEncode) { // 确保get手动编码逻辑只运行一次
	for (String parameterName : parameterMap.keySet()) {
	String[] values = parameterMap.get(parameterName);
	if (values != null) {
	for (int i = 0; i < values.length; i++) {
	// 处理get乱码
	values[i] = new String(values[i]
	.getBytes(StandardCharsets.ISO_8859_1), StandardCharsets.UTF_8);
	}
	}
	}
	hasEncode = true;
	}
	return parameterMap;
	}
	return super.getParameterMap();
	}
	//取一个值
	@Override
	public String getParameter(String name) {
	Map<String, String[]> parameterMap = getParameterMap();
	String[] values = parameterMap.get(name);
	if (values == null) {
	return null;
	}
	return values[0]; // 取回参数的第一个值
	}
	//取所有值
	@Override
	public String[] getParameterValues(String name) {
	Map<String, String[]> parameterMap = getParameterMap();
	return parameterMap.get(name);
	}
	}

	<!--自定义编码过滤器-->
	<filter>
	<filter-name>encoding</filter-name>
	<filter-class>com.lv.filter.GenericEncodingFilter</filter-class>
	</filter>
	<filter-mapping>
	<filter-name>encoding</filter-name>
	<url-pattern>/*</url-pattern>
	</filter-mapping>