• J2EE基础-通用分页(2)

    目录

    前言

    一、改造pagebean

    分页核心思路

     PageBean类：

    新建一个 BookServlet :

    .jsp代码

    从Servlet运行结果：

    二、通用分页

    分页jsp:

    PageTag助手类：

    tld配置文件：

    优化PageBean：

    在bookList.jsp内导入y标签和c标签：

    优化BookServlet：

    再通过标签将数据遍历出来展示在页面上：

     中文乱码处理类：

    前言

    上次我们分享了通用分页的后台代码(http://t.csdn.cn/WaVH1)，今天分享的内容通用分页的前端代码

    一、改造pagebean

    分页核心思路

     通过上图的得出一下思路

    1. 需要新增变量保存上一次查询条件
    2. 需要新增变量保存上一次请求地址：http://localhost:80/oyang_page/book/search
    3. 需要添加方法：获取最大页的页码
    4. 需要添加方法：获取下一页的页码
    5. 需要添加方法：获取上一页的页码
    6. 需要新增方法：初始化pagebean

     PageBean类：

    1. package com.oyang.util;
    2.  
    3. import java.util.HashMap;
    4. import java.util.Map;
    5.  
    6. import javax.servlet.http.HttpServletRequest;
    7.  
    8. /**
    9.  * 分页工具类
    10.  *
    11.  */
    12. public class PageBean {
    13.  
    14. 	private int page = 1;// 页码
    15.  
    16. 	private int rows = 10;// 页大小
    17.  
    18. 	private int total = 0;// 总记录数
    19.  
    20. 	private boolean pagination = true;// 是否分页
    21.  
    22. 	
    23. //	需要新增变量保存上一次查询条件
    24. 	private Map<String, String[]> parameterMap=new HashMap<String,String[]>();
    25. 	
    26. //	需要新增变量保存上一次请求地址：http://localhost:80/oyang_page/book/search
    27. 	private String url;
    28. 	
    29. //	需要添加方法：获取最大页的页码
    30. 	public int maxPage() {
    31. 		return this.total%this.rows ==0?this.total /this.rows :this.total/this.rows+1;
    32. 	}
    33. 	
    34. //	需要添加方法：获取上一页的页码
    35. 	public int previousPage() {
    36. 		return this.page>1?this.page-1:this.page;
    37. 	}
    38. 	
    39. //	需要添加方法：获取下一页的页码
    40. 	public int nextPage() {
    41. 		return this.page<this.maxPage()?this.page+1:this.page;
    42. 	}
    43. 	
    44. //	需要新增方法：初始化pagebean
    45. 	 public void serRequest(HttpServletRequest request) {
    46. 		 this.setPage(request.getParameter("page"));
    47. 		 this.setRows(request.getParameter("rows"));
    48. 		 this.setPagination(request.getParameter("pagination"));
    49. 		 this.setUrl(request.getRequestURL().toString());
    50. 		 System.out.println(request.getRequestURL().toString());
    51. 		 this.setParameterMap(request.getParameterMap());
    52. 	 }
    53. 	
    54. 	
    55. 	
    56. 	private void setPagination(String pagination) {
    57. 		if(StringUtils.isNotBlank(pagination)) {
    58. 			this.setPagination("false".equals(pagination));
    59. 		}
    60. }
    61.  
    62. 	private void setRows(String rows) {
    63. 		if(StringUtils.isNotBlank(rows)) {
    64. 			this.setRows(Integer.valueOf(rows));
    65. 		}
    66. 	}
    67.  
    68. 	public void setPage(String page) {
    69. 		if(StringUtils.isNotBlank(page)) {
    70. 			//set自动生成的方法
    71. 			this.setPage(Integer.valueOf(page));
    72. 		}
    73. 	}
    74.  
    75. 	public PageBean() {
    76. 		super();
    77. 	}
    78.  
    79. 	public Map<String, String[]> getParameterMap() {
    80. 		return parameterMap;
    81. 	}
    82.  
    83. 	public void setParameterMap(Map<String, String[]> parameterMap) {
    84. 		this.parameterMap = parameterMap;
    85. 	}
    86.  
    87. 	public String getUrl() {
    88. 		return url;
    89. 	}
    90.  
    91. 	public void setUrl(String url) {
    92. 		this.url = url;
    93. 	}
    94.  
    95. 	public int getPage() {
    96. 		return page;
    97. 	}
    98.  
    99. 	public void setPage(int page) {
    100. 		this.page = page;
    101. 	}
    102.  
    103. 	public int getRows() {
    104. 		return rows;
    105. 	}
    106.  
    107. 	public void setRows(int rows) {
    108. 		this.rows = rows;
    109. 	}
    110.  
    111. 	public int getTotal() {
    112. 		return total;
    113. 	}
    114.  
    115. 	public void setTotal(int total) {
    116. 		this.total = total;
    117. 	}
    118.  
    119. 	public void setTotal(String total) {
    120. 		this.total = Integer.parseInt(total);
    121. 	}
    122.  
    123. 	public boolean isPagination() {
    124. 		return pagination;
    125. 	}
    126.  
    127. 	public void setPagination(boolean pagination) {
    128. 		this.pagination = pagination;
    129. 	}
    130.  
    131. 	/**
    132. 	 * 获得起始记录的下标
    133. 	 * 
    134. 	 * @return
    135. 	 */
    136. 	public int getStartIndex() {
    137. 		return (this.page - 1) * this.rows;
    138. 	}
    139.  
    140. 	@Override
    141. 	public String toString() {
    142. 		return "PageBean [page=" + page + ", rows=" + rows + ", total=" + total + ", pagination=" + pagination
    143. 				+ ", parameterMap=" + parameterMap + ", url=" + url + "]";
    144. 	}
    145. 	
    146. 	
    147. }

    新建一个 BookServlet :

    1. package 	com.oyang.servlet;
    2.  
    3. import java.io.IOException;
    4. import java.util.List;
    5. import java.util.Map;
    6.  
    7. import javax.servlet.ServletException;
    8. import javax.servlet.annotation.WebServlet;
    9. import javax.servlet.http.HttpServlet;
    10. import javax.servlet.http.HttpServletRequest;
    11. import javax.servlet.http.HttpServletResponse;
    12.  
    13. import com.oyang.dao.BookDao;
    14. import com.oyang.entity.Book;
    15. import com.oyang.util.PageBean;
    16.  
    17.  
    18. @WebServlet("/book/search")
    19. public class BookServlet extends HttpServlet {
    20. 	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    21. 		doPost(request, response);
    22. 	}
    23.  
    24. 	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    25. 		PageBean pageBean=new PageBean();
    26. 		pageBean.serRequest(request);
    27.  
    28. 		
    29. 		request.setAttribute("pageBean", pageBean);
    30. 		request.getRequestDispatcher("/bookList.jsp").forward(request, response);
    31. 	}
    32.  
    33. }

    .jsp代码

    1. <%@ page language="java" contentType="text/html; charset=UTF-8"
    2.     pageEncoding="UTF-8"%>
    3. <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
    4. <html>
    5. <head>
    6. <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
    7. <title>Insert title here</title>
    8. </head>
    9. <body>
    10. ${pageBean}
    11. </body>
    12. </html>

    从Servlet运行结果：

     当我们能够拿到数据的时候改造就OK了

    二、通用分页

    分页jsp:

    1.  
    2. <%@ page language="java" contentType="text/html; charset=UTF-8"
    3. 	pageEncoding="UTF-8"%>
    4. <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
    5. <html>
    6. <head>
    7. <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
    8. <link
    9. 	href="https://cdn.bootcdn.net/ajax/libs/twitter-bootstrap/4.5.0/css/bootstrap.css"
    10. 	rel="stylesheet">
    11. <script
    12. 	src="https://cdn.bootcdn.net/ajax/libs/twitter-bootstrap/4.5.0/js/bootstrap.js"></script>
    13. <title>书籍列表</title>
    14. <style type="text/css">
    15. .page-item input {
    16. 	padding: 0;
    17. 	width: 40px;
    18. 	height: 100%;
    19. 	text-align: center;
    20. 	margin: 0 6px;
    21. }
    22.  
    23. .page-item input, .page-item b {
    24. 	line-height: 38px;
    25. 	float: left;
    26. 	font-weight: 400;
    27. }
    28.  
    29. .page-item.go-input {
    30. 	margin: 0 10px;
    31. }
    32. </style>
    33. </head>
    34. <body>
    35. 	<form class="form-inline"
    36. 		action="${pageContext.request.contextPath }/book.action" method="post">
    37. 		<div class="form-group mb-2">
    38. 			<input type="text" class="form-control-plaintext" name="bname"
    39. 				placeholder="请输入书籍名称">
    40. 		</div>
    41. 		<button type="submit" class="btn btn-primary mb-2">查询</button>
    42. 	</form>
    43.  
    44. 	<table class="table table-striped ">
    45. 		<thead>
    46. 			<tr>
    47. 				<th scope="col">书籍ID</th>
    48. 				<th scope="col">书籍名</th>
    49. 				<th scope="col">价格</th>
    50. 			</tr>
    51. 		</thead>
    52. 		<tbody>
    53. 			<tr>
    54. 				<td>1</td>
    55. 				<td>圣墟第1章</td>
    56. 				<td>1</td>
    57. 			</tr>
    58. 			<tr>
    59. 				<td>1</td>
    60. 				<td>圣墟第1章</td>
    61. 				<td>1</td>
    62. 			</tr>
    63.  
    64. 		</tbody>
    65. 	</table>
    66. </body>
    67. </html>

     目前我们的页面效果是这样的，数据暂时都是无效的定死的数据，并且无法查看上一页、下一页、尾页：所以我们还需要继续改写：

    PageTag助手类：

    1. package com.zking.tag;
    2.  
    3. import java.io.IOException;
    4. import java.util.Map;
    5. import java.util.Map.Entry;
    6. import java.util.Set;
    7.  
    8. import javax.servlet.jsp.JspException;
    9. import javax.servlet.jsp.JspWriter;
    10. import javax.servlet.jsp.tagext.BodyTagSupport;
    11.  
    12. import com.oyang.util.PageBean;
    13.  
    14. public class PageTag extends BodyTagSupport{
    15. 	
    16. 	private PageBean pageBean;
    17. 	
    18. 	
    19. 	
    20. 	public PageBean getPageBean() {
    21. 		return pageBean;
    22. 	}
    23.  
    24. 	public void setPageBean(PageBean pageBean) {
    25. 		this.pageBean = pageBean;
    26. 	}
    27.  
    28. 	@Override
    29. 	public int doStartTag() throws JspException {
    30. 		JspWriter out = pageContext.getOut();
    31. 		try {
    32. 			out.print(toHTML());
    33. 		} catch (Exception e) {
    34. 			// TODO Auto-generated catch block
    35. 			e.printStackTrace();
    36. 		}
    37. 		return super.doStartTag();
    38. 	}
    39.  
    40. 	private String toHTML() {
    41. 		StringBuffer sb=new StringBuffer();
    42. 		//隐藏的form表达，作用保存上一次查询条件
    43. 		sb.append("<form action='"+pageBean.getUrl()+"' id='pageBeanForm' method='post'>");
    44. 		sb.append(" 	<input type='hidden' name='page' value=''>");
    45. 		Map<String, String[]> parameterMap = pageBean.getParameterMap();
    46. 		if(parameterMap!=null&&parameterMap.size()>0) {
    47. 			Set<Entry<String, String[]>> entrySet = parameterMap.entrySet();
    48. 			for (Entry<String, String[]> entry : entrySet) {
    49. 				String key=entry.getKey();//name/likes/page/rows
    50. 				String[] values = entry.getValue();
    51. 				if(!"page".equals(key)) {
    52. 					for (String value : values) {
    53. 						sb.append(" 	<input type='hidden' name='"+key+"' value='"+value+"'>");
    54. 					}
    55. 				}
    56. 			}
    57. 		}
    58. 		sb.append("	</form>");
    59.  
    60. 		//分页条
    61. 		sb.append("<ul class='pagination justify-content-center'>");
    62. 		sb.append(" <li class='page-item "+(pageBean.getPage()==1? "disabled":"")+"'><a class='page-link'");
    63. 		sb.append(" 	href='javascript:gotoPage(1)'>首页</a></li>");
    64. 		sb.append(" <li class='page-item "+(pageBean.getPage()==1? "disabled":"")+"'><a class='page-link'");
    65. 		sb.append(" 	href='javascript:gotoPage("+pageBean.previousPage()+")'>&lt;</a></li>");
    66. 		sb.append("	<li class='page-item'><a class='page-link' href='#'>1</a></li>");
    67. 		sb.append(" <li class='page-item'><a class='page-link' href='#'>2</a></li>");
    68. 		sb.append(" <li class='page-item active'><a class='page-link' href='#'>"+pageBean.getPage()+"</a></li>");
    69. 		sb.append(" <li class='page-item "+(pageBean.getPage()==pageBean.maxPage()? "disabled":"")+"'><a class='page-link' href='javascript:gotoPage("+pageBean.nextPage()+")'>&gt;</a></li>");
    70. 		sb.append(" <li class='page-item "+(pageBean.getPage()==pageBean.maxPage()? "disabled":"")+"'><a class='page-link' href='javascript:gotoPage("+pageBean.maxPage()+")'>尾页</a></li>");
    71. 		sb.append(" <li class='page-item go-input'><b>到第</b><input class='page-link'");
    72. 		sb.append("		type='text' id='skipPage' name='' /><b>页</b></li>");
    73. 		sb.append("	<li class='page-item go'><a class='page-link'");
    74. 		sb.append("		href='javascript:skipPage()'>确定</a></li>");
    75. 		sb.append("	<li class='page-item'><b>共"+pageBean.getTotal()+"条</b></li>");
    76. 		sb.append("</ul>");
    77. 		
    78. 		//分页jsp代码
    79. 		sb.append("<script type='text/javascript'>");
    80. 		sb.append("	function gotoPage(page) {");
    81. 		sb.append(" 	document.getElementById('pageBeanForm').page.value = page;");
    82. 		sb.append("		document.getElementById('pageBeanForm').submit();");
    83. 		sb.append("	}");
    84. 		sb.append("	function skipPage() {");
    85. 		sb.append("		var page = document.getElementById('skipPage').value;");
    86. 		sb.append(" 	if (!page || isNaN(page) || parseInt(page) < 1");
    87. 		sb.append("		|| parseInt(page) > "+pageBean.maxPage()+") {");
    88. 		sb.append("			alert('请输入1~"+pageBean.maxPage()+"的数字');");
    89. 		sb.append("			return;");
    90. 		sb.append("		}");
    91. 		sb.append("	 gotoPage(page);");
    92. 		sb.append(" }");
    93. 		sb.append("	</script>");
    94. 		
    95. 		return sb.toString();
    96. 	}
    97. }

    tld配置文件：

    1. <?xml version="1.0" encoding="UTF-8" ?>
    2.  
    3. <taglib xmlns="http://java.sun.com/xml/ns/j2ee"
    4.     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    5.     xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/web-jsptaglibrary_2_0.xsd"
    6.     version="2.0">
    7.     
    8.   <description>JSTL 1.1 core library</description>
    9.   <display-name>JSTL core</display-name>
    10.   <tlib-version>1.1</tlib-version>
    11.   <short-name>y</short-name>
    12.   <uri>https://blog.csdn.net/weixin_65211978?type=blog</uri>
    13.  
    14.   <validator>
    15.     <description>
    16.         Provides core validation features for JSTL tags.
    17.     </description>
    18.     <validator-class>
    19.         org.apache.taglibs.standard.tlv.JstlCoreTLV
    20.     </validator-class>
    21.   </validator>
    22.  
    23.   
    24.   <tag>
    25.     <name>page</name>
    26.     <tag-class>com.zking.tag.PageTag</tag-class>
    27.     <body-content>JSP</body-content>
    28.      <attribute> 
    29.         <name>pageBean</name>
    30.         <required>true</required>
    31.         <rtexprvalue>true</rtexprvalue>
    32.     </attribute>
    33.   </tag>
    34.  
    35.   
    36. </taglib>

    优化PageBean：

    分页很多东西不用改变，但是其中有一个参数要变，那就是page（页数）

    1. package com.oyang.util;
    2.  
    3. import java.util.HashMap;
    4. import java.util.Map;
    5.  
    6. import javax.servlet.http.HttpServletRequest;
    7.  
    8. /**
    9.  * 分页工具类
    10.  *
    11.  */
    12. public class PageBean {
    13.  
    14. 	private int page = 1;// 页码
    15.  
    16. 	private int rows = 10;// 页大小
    17.  
    18. 	private int total = 0;// 总记录数
    19.  
    20. 	private boolean pagination = true;// 是否分页
    21.  
    22. 	
    23. //	需要新增变量保存上一次查询条件
    24. 	private Map<String, String[]> parameterMap=new HashMap<String,String[]>();
    25. 	
    26. //	需要新增变量保存上一次请求地址：http://localhost:80/oyang_page/book/search
    27. 	private String url;
    28. 	
    29. //	需要添加方法：获取最大页的页码
    30. 	public int maxPage() {
    31. 		return this.total%this.rows ==0?this.total /this.rows :this.total/this.rows+1;
    32. 	}
    33. 	
    34. //	需要添加方法：获取上一页的页码
    35. 	public int previousPage() {
    36. 		return this.page>1?this.page-1:this.page;
    37. 	}
    38. 	
    39. //	需要添加方法：获取下一页的页码
    40. 	public int nextPage() {
    41. 		return this.page<this.maxPage()?this.page+1:this.page;
    42. 	}
    43. 	
    44. //	需要新增方法：初始化pagebean
    45. 	 public void serRequest(HttpServletRequest request) {
    46. 		 this.setPage(request.getParameter("page"));
    47. 		 this.setRows(request.getParameter("rows"));
    48. 		 this.setPagination(request.getParameter("pagination"));
    49. 		 this.setUrl(request.getRequestURL().toString());
    50. 		 System.out.println(request.getRequestURL().toString());
    51. 		 this.setParameterMap(request.getParameterMap());
    52. 	 }
    53. 	
    54. 	
    55. 	
    56. 	private void setPagination(String pagination) {
    57. 		if(StringUtils.isNotBlank(pagination)) {
    58. 			this.setPagination("false".equals(pagination));
    59. 		}
    60. }
    61.  
    62. 	private void setRows(String rows) {
    63. 		if(StringUtils.isNotBlank(rows)) {
    64. 			this.setRows(Integer.valueOf(rows));
    65. 		}
    66. 	}
    67.  
    68. 	public void setPage(String page) {
    69. 		if(StringUtils.isNotBlank(page)) {
    70. 			//set自动生成的方法
    71. 			this.setPage(Integer.valueOf(page));
    72. 		}
    73. 	}
    74.  
    75. 	public PageBean() {
    76. 		super();
    77. 	}
    78.  
    79. 	public Map<String, String[]> getParameterMap() {
    80. 		return parameterMap;
    81. 	}
    82.  
    83. 	public void setParameterMap(Map<String, String[]> parameterMap) {
    84. 		this.parameterMap = parameterMap;
    85. 	}
    86.  
    87. 	public String getUrl() {
    88. 		return url;
    89. 	}
    90.  
    91. 	public void setUrl(String url) {
    92. 		this.url = url;
    93. 	}
    94.  
    95. 	public int getPage() {
    96. 		return page;
    97. 	}
    98.  
    99. 	public void setPage(int page) {
    100. 		this.page = page;
    101. 	}
    102.  
    103. 	public int getRows() {
    104. 		return rows;
    105. 	}
    106.  
    107. 	public void setRows(int rows) {
    108. 		this.rows = rows;
    109. 	}
    110.  
    111. 	public int getTotal() {
    112. 		return total;
    113. 	}
    114.  
    115. 	public void setTotal(int total) {
    116. 		this.total = total;
    117. 	}
    118.  
    119. 	public void setTotal(String total) {
    120. 		this.total = Integer.parseInt(total);
    121. 	}
    122.  
    123. 	public boolean isPagination() {
    124. 		return pagination;
    125. 	}
    126.  
    127. 	public void setPagination(boolean pagination) {
    128. 		this.pagination = pagination;
    129. 	}
    130.  
    131. 	/**
    132. 	 * 获得起始记录的下标
    133. 	 * 
    134. 	 * @return
    135. 	 */
    136. 	public int getStartIndex() {
    137. 		return (this.page - 1) * this.rows;
    138. 	}
    139.  
    140. 	@Override
    141. 	public String toString() {
    142. 		return "PageBean [page=" + page + ", rows=" + rows + ", total=" + total + ", pagination=" + pagination
    143. 				+ ", parameterMap=" + parameterMap + ", url=" + url + "]";
    144. 	}
    145. 	
    146. 	
    147. }

    在bookList.jsp内导入y标签和c标签：

    1. <%@taglib uri="https://blog.csdn.net/weixin_65211978?type=blog" prefix="y" %>
    2. <%@taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%>

    优化BookServlet：

    1. package 	com.oyang.servlet;
    2.  
    3. import java.io.IOException;
    4. import java.util.List;
    5. import java.util.Map;
    6.  
    7. import javax.servlet.ServletException;
    8. import javax.servlet.annotation.WebServlet;
    9. import javax.servlet.http.HttpServlet;
    10. import javax.servlet.http.HttpServletRequest;
    11. import javax.servlet.http.HttpServletResponse;
    12.  
    13. import com.oyang.dao.BookDao;
    14. import com.oyang.entity.Book;
    15. import com.oyang.util.PageBean;
    16.  
    17.  
    18. @WebServlet("/book/search")
    19. public class BookServlet extends HttpServlet {
    20. 	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    21. 		doPost(request, response);
    22. 	}
    23.  
    24. 	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    25. 		PageBean pageBean=new PageBean();
    26. 		pageBean.serRequest(request);
    27. 		
    28. 		BookDao bd=new  BookDao();
    29. 		Book book=new Book();
    30. 		book.setBname(request.getParameter("bname"));
    31. 		try {
    32. 			List<Book> books = bd.list2(book, pageBean);
    33. 			request.setAttribute("books", books);
    34. 		} catch (Exception e) {
    35. 			// TODO Auto-generated catch block
    36. 			e.printStackTrace();
    37. 		}
    38. 		
    39. 		request.setAttribute("pageBean", pageBean);
    40. 		request.getRequestDispatcher("/bookList.jsp").forward(request, response);
    41. 	}
    42.  
    43. }

    再通过标签将数据遍历出来展示在页面上：

    1. 		 <c:forEach items="${books}" var="b"> 
    2. 			<tr>
    3. 				<td>${b.bid}</td>
    4. 				<td>${b.bname}</td>
    5. 				<td>${b.price}</td>
    6. 			</tr>
    7. 		</c:forEach>
    8. 		</tbody>
    9. 	</table>
    10. 	
    11. 	<y:page pageBean="${pageBean}"></y:page>

    结束完这些后你会发现，在查询的时候会出现乱码问题，这时候我们需要加上一个过滤器 

     中文乱码处理类：

    1. package com.oyang.util;
    2.  
    3. import java.io.IOException;
    4. import java.util.Iterator;
    5. import java.util.Map;
    6. import java.util.Set;
    7.  
    8. import javax.servlet.Filter;
    9. import javax.servlet.FilterChain;
    10. import javax.servlet.FilterConfig;
    11. import javax.servlet.ServletException;
    12. import javax.servlet.ServletRequest;
    13. import javax.servlet.ServletResponse;
    14. import javax.servlet.annotation.WebFilter;
    15. import javax.servlet.http.HttpServletRequest;
    16. import javax.servlet.http.HttpServletResponse;
    17.  
    18. /**
    19.  * 中文乱码处理
    20.  * 
    21.  */
    22. @WebFilter("/book/*")
    23. public class EncodingFiter implements Filter {
    24.  
    25. 	private String encoding = "UTF-8";// 默认字符集
    26.  
    27. 	public EncodingFiter() {
    28. 		super();
    29. 	}
    30.  
    31. 	public void destroy() {
    32. 	}
    33.  
    34. 	public void doFilter(ServletRequest request, ServletResponse response,
    35. 			FilterChain chain) throws IOException, ServletException {
    36. 		HttpServletRequest req = (HttpServletRequest) request;
    37. 		HttpServletResponse res = (HttpServletResponse) response;
    38.  
    39. 		// 中文处理必须放到 chain.doFilter(request, response)方法前面
    40. 		res.setContentType("text/html;charset=" + this.encoding);
    41. 		if (req.getMethod().equalsIgnoreCase("post")) {
    42. 			req.setCharacterEncoding(this.encoding);
    43. 		} else {
    44. 			Map map = req.getParameterMap();// 保存所有参数名=参数值(数组)的Map集合
    45. 			Set set = map.keySet();// 取出所有参数名
    46. 			Iterator it = set.iterator();
    47. 			while (it.hasNext()) {
    48. 				String name = (String) it.next();
    49. 				String[] values = (String[]) map.get(name);// 取出参数值[注：参数值为一个数组]
    50. 				for (int i = 0; i < values.length; i++) {
    51. 					values[i] = new String(values[i].getBytes("ISO-8859-1"),
    52. 							this.encoding);
    53. 				}
    54. 			}
    55. 		}
    56.  
    57. 		chain.doFilter(request, response);
    58. 	}
    59.  
    60. 	public void init(FilterConfig filterConfig) throws ServletException {
    61. 		String s = filterConfig.getInitParameter("encoding");// 读取web.xml文件中配置的字符集
    62. 		if (null != s && !s.trim().equals("")) {
    63. 			this.encoding = s.trim();
    64. 		}
    65. 	}
    66.  
    67. }

     OK，今日的学习就到此结束啦，如果对个位看官有帮助的话可以留下免费的赞哦(收藏或关注也行),如果文章中有什么问题或不足以及需要改正的地方可以私信博主，博主会做出改正的。个位看官，小陽在此跟大家说拜拜啦！ 

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  • 原文地址：https://blog.csdn.net/weixin_65211978/article/details/125443238