Spring+SpringMVC+MyBatis（SSM）CRM 客户关系管理系统项目案例（可运行）

package com.itheima.common.utils; import java.io.IOException; import java.util.Map; import javax.servlet.http.HttpServletRequest; import javax.servlet.jsp.JspException; import javax.servlet.jsp.JspWriter; import javax.servlet.jsp.tagext.TagSupport; import org.apache.taglibs.standard.tag.common.core.UrlSupport; /** * 显示格式 上一页 1 2 3 4 5 下一页 */ public class NavigationTag extends TagSupport { static final long serialVersionUID = 2372405317744358833L; /** * request 中用于保存Page<E> 对象的变量名,默认为“page” */ private String bean = "page"; /** * 分页跳转的url地址,此属性必须 */ private String url = null; /** * 显示页码数量 */ private int number = 5; @Override public int doStartTag() throws JspException { JspWriter writer = pageContext.getOut(); HttpServletRequest request = (HttpServletRequest) pageContext.getRequest(); Page page = (Page)request.getAttribute(bean); if (page == null) return SKIP_BODY; url = resolveUrl(url, pageContext); try { //计算总页数 int pageCount = page.getTotal() / page.getSize(); if (page.getTotal() % page.getSize() > 0) { pageCount++; } writer.print("<nav><ul class=\"pagination\">"); //显示“上一页”按钮 if (page.getPage() > 1) { String preUrl = append(url, "page", page.getPage() - 1); preUrl = append(preUrl, "rows", page.getSize()); writer.print("<li><a href=\"" + preUrl + "\">上一页</a></li>"); } else { writer.print("<li class=\"disabled\"><a href=\"#\">上一页</a></li>"); } //显示当前页码的前2页码和后两页码 //若1 则 1 2 3 4 5, 若2 则 1 2 3 4 5, 若3 则1 2 3 4 5, //若4 则 2 3 4 5 6 ,若10 则 8 9 10 11 12 int indexPage = (page.getPage() - 2 > 0)? page.getPage() - 2 : 1; for(int i=1; i <= number && indexPage <= pageCount; indexPage++, i++) { if(indexPage == page.getPage()) { writer.print( "<li class=\"active\"><a href=\"#\">"+indexPage+"<span class=\"sr-only\">(current)</span></a></li>"); continue; } String pageUrl = append(url, "page", indexPage); pageUrl = append(pageUrl, "rows", page.getSize()); writer.print("<li><a href=\"" + pageUrl + "\">"+ indexPage +"</a></li>"); } //显示“下一页”按钮 if (page.getPage() < pageCount) { String nextUrl = append(url, "page", page.getPage() + 1); nextUrl = append(nextUrl, "rows", page.getSize()); writer.print("<li><a href=\"" + nextUrl + "\">下一页</a></li>"); } else { writer.print("<li class=\"disabled\"><a href=\"#\">下一页</a></li>"); } writer.print("</nav>"); } catch (IOException e) { e.printStackTrace(); } return SKIP_BODY; } private String append(String url, String key, int value) { return append(url, key, String.valueOf(value)); } /** * 为url 参加参数对儿 * * @param url * @param key * @param value * @return */ private String append(String url, String key, String value) { if (url == null || url.trim().length() == 0) { return ""; } if (url.indexOf("?") == -1) { url = url + "?" + key + "=" + value; } else { if(url.endsWith("?")) { url = url + key + "=" + value; } else { url = url + "&amp;" + key + "=" + value; } } return url; } /** * 为url 添加翻页请求参数 * * @param url * @param pageContext * @return * @throws javax.servlet.jsp.JspException */ private String resolveUrl(String url, javax.servlet.jsp.PageContext pageContext) throws JspException{ //UrlSupport.resolveUrl(url, context, pageContext) Map params = pageContext.getRequest().getParameterMap(); for (Object key:params.keySet()) { if ("page".equals(key) || "rows".equals(key)) continue; Object value = params.get(key); if (value == null) continue; if (value.getClass().isArray()) { url = append(url, key.toString(), ((String[])value)[0]); } else if (value instanceof String) { url = append(url, key.toString(), value.toString()); } } return url; } /** * @return the bean */ public String getBean() { return bean; } /** * @param bean the bean to set */ public void setBean(String bean) { this.bean = bean; } /** * @return the url */ public String getUrl() { return url; } /** * @param url the url to set */ public void setUrl(String url) { this.url = url; } public void setNumber(int number) { this.number = number; } }