springmvc中的编码过滤器

在web.xml中编写一下代码

<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>

  

让我们来读读这个过滤器，此处有三个属性，一个是编码，一个是强制request编码，一个是强制response编码

private String encoding;

private boolean forceRequestEncoding = false;

private boolean forceResponseEncoding = false;

 

然后来看一下构造器；

public CharacterEncodingFilter() {
	}

public CharacterEncodingFilter(String encoding) {
		this(encoding, false);
}

public CharacterEncodingFilter(String encoding, boolean forceEncoding) {
               this(encoding, forceEncoding, forceEncoding);
	}
public CharacterEncodingFilter(String encoding, boolean forceRequestEncoding, boolean forceResponseEncoding) {
		Assert.hasLength(encoding, "Encoding must not be empty");
		this.encoding = encoding;
		this.forceRequestEncoding = forceRequestEncoding;
		this.forceResponseEncoding = forceResponseEncoding;
	}

 

这里只传了一个参数，就是encoding，然后forceRequestEncoding和forceResponseEncoding都是false,下面主要是一些编码的set和get方法

   public void setEncoding(String encoding) {
		this.encoding = encoding;
	}

	
	public String getEncoding() {
		return this.encoding;
	}
	public void setForceEncoding(boolean forceEncoding) {
		this.forceRequestEncoding = forceEncoding;
		this.forceResponseEncoding = forceEncoding;
	}
	public void setForceRequestEncoding(boolean forceRequestEncoding) {
		this.forceRequestEncoding = forceRequestEncoding;
	}
	public boolean isForceRequestEncoding() {
		return this.forceRequestEncoding;
	}
	public boolean isForceResponseEncoding() {
		return this.forceResponseEncoding;
	}
	public void setForceResponseEncoding(boolean forceResponseEncoding) {
		this.forceResponseEncoding = forceResponseEncoding;
	}

然后是过滤器主要方法

protected void doFilterInternal(
			HttpServletRequest request, HttpServletResponse response, FilterChain filterChain)
			throws ServletException, IOException {

		String encoding = getEncoding();
		if (encoding != null) {
			if (isForceRequestEncoding() || request.getCharacterEncoding() == null) {
				request.setCharacterEncoding(encoding);
			}
			if (isForceResponseEncoding()) {
				response.setCharacterEncoding(encoding);
			}
		}
		filterChain.doFilter(request, response);
	}

然后在这个方法中设定了request和response的编码

Filter过滤器方法,下面的子类使用了模版的继承方式

 

 

public interface Filter {

    public void init(FilterConfig filterConfig) throws ServletException;
//进行初始话
    public void doFilter(ServletRequest request, ServletResponse response,
                         FilterChain chain)
            throws IOException, ServletException;
//进行过滤依靠chain向下传递
    public void destroy();
//进行摧毁时候进行调用
}