Http与Servlet工具类

1、Content Type 定义

public static final String TEXT_TYPE = "text/plain";    public static final String JSON_TYPE = "application/json";    public static final String XML_TYPE = "text/xml";    public static final String HTML_TYPE = "text/html";    public static final String JS_TYPE = "text/javascript";    public static final String EXCEL_TYPE = "application/vnd.ms-excel";

2、Header 定义

public static final String AUTHENTICATION_HEADER = "Authorization";

3、常用数值定义

 public static final long ONE_YEAR_SECONDS = 60 * 60 * 24 * 365;    public static final String HEADER_ENCODING = "encoding";    public static final String HEADER_NOCACHE = "no-cache";    public static final String DEFAULT_ENCODING = "UTF-8";    public static final boolean DEFAULT_NOCACHE = true;

4、设置禁止客户端缓存的Header

public static void setDisableCacheHeader(HttpServletResponse response) {        // Http 1.0 header        response.setDateHeader("Expires", 1L);        response.addHeader("Pragma", "no-cache");        // Http 1.1 header        response.setHeader("Cache-Control", "no-cache, no-store, max-age=0");    }

5、设置客户端缓存过期时间 Header

public static void setExpiresHeader(HttpServletResponse response,            long expiresSeconds) {        // Http 1.0 header        response.setDateHeader("Expires", System.currentTimeMillis()                + expiresSeconds * 1000);        // Http 1.1 header        response.setHeader("Cache-Control", "private, max-age="                + expiresSeconds);    }

6、设置客户端无缓存Header

public static void setNoCacheHeader(HttpServletResponse response) {        // Http 1.0 header        response.setDateHeader("Expires", 0);        response.addHeader("Pragma", "no-cache");        // Http 1.1 header        response.setHeader("Cache-Control", "no-cache");    }

7、分析并设置contentType与headers

 public static void initResponseHeader(HttpServletResponse resp,            String contentType, String... headers) {        // 分析headers参数        String encoding = DEFAULT_ENCODING;        boolean noCache = DEFAULT_NOCACHE;        for (String header : headers) {            String headerName = StringUtils.substringBefore(header, ":");            String headerValue = StringUtils.substringAfter(header, ":");            if (StringUtils.equalsIgnoreCase(headerName, HEADER_ENCODING)) {                encoding = headerValue;            } else if (StringUtils.equalsIgnoreCase(headerName, HEADER_NOCACHE)) {                noCache = Boolean.parseBoolean(headerValue);            } else {                throw new IllegalArgumentException(headerName                        + "不是一个合法的header类型");            }        }        // 设置headers参数        String fullContentType = contentType + ";charset=" + encoding;        resp.setContentType(fullContentType);        if (noCache) {            setNoCacheHeader(resp);        }    }

8、直接输出内容的简便函数

public static void render(HttpServletResponse resp, String contentType,            String content, String... headers) {        initResponseHeader(resp, contentType, headers);        try {            resp.getWriter().write(content);            resp.getWriter().flush();        } catch (IOException e) {            throw new RuntimeException(e.getMessage(), e);        }    }

9、输出文本

public static void renderText(HttpServletResponse resp, String text,            String... headers) {        render(resp, ServletUtils.TEXT_TYPE, text, headers);    }

10、输出html

public static void renderHtml(HttpServletResponse resp, String html,            String... headers) {        render(resp, ServletUtils.HTML_TYPE, html, headers);    }

11、输出xml

public static void renderXml(HttpServletResponse resp, String xml,            String... headers) {        render(resp, ServletUtils.XML_TYPE, xml, headers);    }

12、输出json

public static void renderJson(HttpServletResponse resp, String jsonString,            String... headers) {        render(resp, ServletUtils.TEXT_TYPE, jsonString, headers);    }