jsp实现分页（限定显示指定页数）和页面跳转功能

末蓝、 2023-10-17 13:17 23阅读 0赞

本文主要介绍在jsp中实现分页功能和页面跳转功能，能够实现数据的分页显示和跳转到指定页面的功能，具体效果如图

![Image 1][]![Center][]

由于该功能是一个书城项目的一部分，所以数据来源于该项目，具体[数据库][Link 1](数据库方面采用c3p0连接池，使用的是[MySQL][Link 1]数据库)文件可以在[点击打开链接下载][Link 2]，整个项目可以在[点击打开链接][Link 3]下载（不过由于使用的是MyeElipse2013,所以请使用此版本或者更高版本导入工程）。

下面具体介绍一下这个小功能

1. 这个项目的目录结构：

![Image 1][]

2.显示的数据主要是图书的相关信息因此Bean类是图书Book的相关信息即com.page.book.domain中Book类的相关信息如下

**\[java\]**  view plain  copy

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1.  package com.page.book.domain;
2.  
3.  import org.apache.log4j.Category;
4.  
5.  public class Book \{
6.  private String bid;//主键
7.  private String bname;//图名
8.  private String author;//作者
9.  private double price;//定价
10. private double currPrice;//当前价
11. private double discount;//折扣
12. private String press;//出版社
13. private String publishtime;//出版时间
14. private int edition;//版次
15. private int pageNum;//页数
16. private int wordNum;//字数
17. private String printtime;//刷新时间
18. private int booksize;//开本
19. private String paper;//纸质
20. private Category category;//所属分类
21. private String image\_w;//大图路径
22. private String image\_b;//小图路径
23. public String getBid() \{
24. return bid;
25. \}
26. public void setBid(String bid) \{
27. this.bid = bid;
28. \}
29. public String getBname() \{
30. return bname;
31. \}
32. public void setBname(String bname) \{
33. this.bname = bname;
34. \}
35. public String getAuthor() \{
36. return author;
37. \}
38. public void setAuthor(String author) \{
39. this.author = author;
40. \}
41. public double getPrice() \{
42. return price;
43. \}
44. public void setPrice(double price) \{
45. this.price = price;
46. \}
47. public double getCurrPrice() \{
48. return currPrice;
49. \}
50. public void setCurrPrice(double currPrice) \{
51. this.currPrice = currPrice;
52. \}
53. public double getDiscount() \{
54. return discount;
55. \}
56. public void setDiscount(double discount) \{
57. this.discount = discount;
58. \}
59. public String getPress() \{
60. return press;
61. \}
62. public void setPress(String press) \{
63. this.press = press;
64. \}
65. public String getPublishtime() \{
66. return publishtime;
67. \}
68. public void setPublishtime(String publishtime) \{
69. this.publishtime = publishtime;
70. \}
71. public int getEdition() \{
72. return edition;
73. \}
74. public void setEdition(int edition) \{
75. this.edition = edition;
76. \}
77. public int getPageNum() \{
78. return pageNum;
79. \}
80. public void setPageNum(int pageNum) \{
81. this.pageNum = pageNum;
82. \}
83. public int getWordNum() \{
84. return wordNum;
85. \}
86. public void setWordNum(int wordNum) \{
87. this.wordNum = wordNum;
88. \}
89. public String getPrinttime() \{
90. return printtime;
91. \}
92. public void setPrinttime(String printtime) \{
93. this.printtime = printtime;
94. \}
95. public int getBooksize() \{
96. return booksize;
97. \}
98. public void setBooksize(int booksize) \{
99. this.booksize = booksize;
100. \}
101. public String getPaper() \{
102. return paper;
103. \}
104. public void setPaper(String paper) \{
105. this.paper = paper;
106. \}
107. public Category getCategory() \{
108. return category;
109. \}
110. public void setCategory(Category category) \{
111. this.category = category;
112. \}
113. public String getImage\_w() \{
114. return image\_w;
115. \}
116. public void setImage\_w(String image\_w) \{
117. this.image\_w = image\_w;
118. \}
119. public String getImage\_b() \{
120. return image\_b;
121. \}
122. public void setImage\_b(String image\_b) \{
123. this.image\_b = image\_b;
124. \}
125. \}

![save_snippets.png][]

package com.page.book.domain;
    
    import org.apache.log4j.Category;
    
    public class Book {
    	private String bid;//主键
    	private String bname;//图名
    	private String author;//作者
    	private double price;//定价
    	private double currPrice;//当前价
    	private double discount;//折扣
    	private String press;//出版社
    	private String publishtime;//出版时间
    	private int edition;//版次
    	private int pageNum;//页数
    	private int wordNum;//字数
    	private String printtime;//刷新时间
    	private int booksize;//开本
    	private String paper;//纸质
    	private Category category;//所属分类
    	private String image_w;//大图路径
    	private String image_b;//小图路径
    	public String getBid() {
    		return bid;
    	}
    	public void setBid(String bid) {
    		this.bid = bid;
    	}
    	public String getBname() {
    		return bname;
    	}
    	public void setBname(String bname) {
    		this.bname = bname;
    	}
    	public String getAuthor() {
    		return author;
    	}
    	public void setAuthor(String author) {
    		this.author = author;
    	}
    	public double getPrice() {
    		return price;
    	}
    	public void setPrice(double price) {
    		this.price = price;
    	}
    	public double getCurrPrice() {
    		return currPrice;
    	}
    	public void setCurrPrice(double currPrice) {
    		this.currPrice = currPrice;
    	}
    	public double getDiscount() {
    		return discount;
    	}
    	public void setDiscount(double discount) {
    		this.discount = discount;
    	}
    	public String getPress() {
    		return press;
    	}
    	public void setPress(String press) {
    		this.press = press;
    	}
    	public String getPublishtime() {
    		return publishtime;
    	}
    	public void setPublishtime(String publishtime) {
    		this.publishtime = publishtime;
    	}
    	public int getEdition() {
    		return edition;
    	}
    	public void setEdition(int edition) {
    		this.edition = edition;
    	}
    	public int getPageNum() {
    		return pageNum;
    	}
    	public void setPageNum(int pageNum) {
    		this.pageNum = pageNum;
    	}
    	public int getWordNum() {
    		return wordNum;
    	}
    	public void setWordNum(int wordNum) {
    		this.wordNum = wordNum;
    	}
    	public String getPrinttime() {
    		return printtime;
    	}
    	public void setPrinttime(String printtime) {
    		this.printtime = printtime;
    	}
    	public int getBooksize() {
    		return booksize;
    	}
    	public void setBooksize(int booksize) {
    		this.booksize = booksize;
    	}
    	public String getPaper() {
    		return paper;
    	}
    	public void setPaper(String paper) {
    		this.paper = paper;
    	}
    	public Category getCategory() {
    		return category;
    	}
    	public void setCategory(Category category) {
    		this.category = category;
    	}
    	public String getImage_w() {
    		return image_w;
    	}
    	public void setImage_w(String image_w) {
    		this.image_w = image_w;
    	}
    	public String getImage_b() {
    		return image_b;
    	}
    	public void setImage_b(String image_b) {
    		this.image_b = image_b;
    	}
    }

3.dao层的实现

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1.  package com.page.book.dao;
2.  
3.  import java.sql.SQLException;
4.  import java.util.ArrayList;
5.  import java.util.List;
6.  
7.  import org.apache.commons.dbutils.QueryRunner;
8.  import org.apache.commons.dbutils.handlers.BeanListHandler;
9.  import org.apache.commons.dbutils.handlers.ScalarHandler;
10. 
11. import cn.itcast.jdbc.TxQueryRunner;
12. 
13. import com.page.book.domain.Book;
14. import com.page.pager.Expression;
15. import com.page.pager.PageBean;
16. import com.page.pager.PageConstants;
17. 
18. public class BookDao \{
19. private QueryRunner qr = new TxQueryRunner();
20. 
21. /\*\*
22.  \* 按分类查询
23.  \* @param cid
24.  \* @param pc
25.  \* @return
26.  \* @throws SQLException 
27.  \*/
28. public PageBean<Book> findByCategory(String cid, int pc) throws SQLException \{
29. List<Expression> exprList = new ArrayList<Expression>();
30. exprList.add(new Expression("cid", "=", cid));
31. return findByCriteria(exprList, pc);
32. \}
33. 
34. 
35. 
36. 
37. /\*\*
38.  \* 通用的查询方法
39.  \* @param exprList
40.  \* @param pc
41.  \* @return
42.  \* @throws SQLException 
43.  \*/
44. private PageBean<Book> findByCriteria(List<Expression> exprList, int pc) throws SQLException \{
45. /\*
46.  \* 1. 得到ps
47.  \* 2. 得到tr
48.  \* 3. 得到beanList
49.  \* 4. 创建PageBean，返回
50.  \*/
51. /\*
52.  \* 1. 得到ps
53.  \*/
54. int ps = PageConstants.BOOK\_PAGE\_SIZE;//每页记录数
55. /\*
56.  \* 2. 通过exprList来生成where子句
57.  \*/
58. StringBuilder whereSql = new StringBuilder(" where 1=1");
59. List<Object> params = new ArrayList<Object>();//SQL中有问号，它是对应问号的值
60. for(Expression expr : exprList) \{
61. /\*
62.  \* 添加一个条件上，
63.  \* 1) 以and开头
64.  \* 2) 条件的名称
65.  \* 3) 条件的运算符，可以是=、!=、>、< ... is null，is null没有值
66.  \* 4) 如果条件不是is null，再追加问号，然后再向params中添加一与问号对应的值
67.  \*/
68. whereSql.append(" and ").append(expr.getName())
69. .append(" ").append(expr.getOperator()).append(" ");
70. // where 1=1 and bid = ?
71. if(!expr.getOperator().equals("is null")) \{
72. whereSql.append("?");
73. params.add(expr.getValue());
74. \}
75. \}
76. 
77. /\*
78.  \* 3. 总记录数 
79.  \*/
80. String sql = "select count(\*) from t\_book" \+ whereSql;
81. Number number = (Number)qr.query(sql, new ScalarHandler(), params.toArray());
82. int tr = number.intValue();//得到了总记录数
83. /\*
84.  \* 4. 得到beanList，即当前页记录
85.  \*/
86. sql = "select \* from t\_book" \+ whereSql + " order by orderBy limit ?,?";
87. params.add((pc-1) \* ps);//当前页首行记录的下标
88. params.add(ps);//一共查询几行，就是每页记录数
89. 
90. List<Book> beanList = qr.query(sql, new BeanListHandler<Book>(Book.class),
91. params.toArray());
92. 
93. /\*
94.  \* 5. 创建PageBean，设置参数
95.  \*/
96. PageBean<Book> pb = new PageBean<Book>();
97. /\*
98.  \* 其中PageBean没有url，这个任务由Servlet完成
99.  \*/
100. pb.setBeanList(beanList);
101. pb.setPc(pc);
102. pb.setPs(ps);
103. pb.setTr(tr);
104. 
105. return pb;
106. \}
107. 
108. 
109. \}

![save_snippets.png][]

package com.page.book.dao;
    
    import java.sql.SQLException;
    import java.util.ArrayList;
    import java.util.List;
    
    import org.apache.commons.dbutils.QueryRunner;
    import org.apache.commons.dbutils.handlers.BeanListHandler;
    import org.apache.commons.dbutils.handlers.ScalarHandler;
    
    import cn.itcast.jdbc.TxQueryRunner;
    
    import com.page.book.domain.Book;
    import com.page.pager.Expression;
    import com.page.pager.PageBean;
    import com.page.pager.PageConstants;
    
    public class BookDao {
    	private QueryRunner qr = new TxQueryRunner();
    	
    	/**
    	 * 按分类查询
    	 * @param cid
    	 * @param pc
    	 * @return
    	 * @throws SQLException 
    	 */
    	public PageBean<Book> findByCategory(String cid, int pc) throws SQLException {
    		List<Expression> exprList = new ArrayList<Expression>();
    		exprList.add(new Expression("cid", "=", cid));
    		return findByCriteria(exprList, pc);
    	}
    	
    
    
    	
    	/**
    	 * 通用的查询方法
    	 * @param exprList
    	 * @param pc
    	 * @return
    	 * @throws SQLException 
    	 */
    	private PageBean<Book> findByCriteria(List<Expression> exprList, int pc) throws SQLException {
    		/*
    		 * 1. 得到ps
    		 * 2. 得到tr
    		 * 3. 得到beanList
    		 * 4. 创建PageBean，返回
    		 */
    		/*
    		 * 1. 得到ps
    		 */
    		int ps = PageConstants.BOOK_PAGE_SIZE;//每页记录数
    		/*
    		 * 2. 通过exprList来生成where子句
    		 */
    		StringBuilder whereSql = new StringBuilder(" where 1=1"); 
    		List<Object> params = new ArrayList<Object>();//SQL中有问号，它是对应问号的值
    		for(Expression expr : exprList) {
    			/*
    			 * 添加一个条件上，
    			 * 1) 以and开头
    			 * 2) 条件的名称
    			 * 3) 条件的运算符，可以是=、!=、>、< ... is null，is null没有值
    			 * 4) 如果条件不是is null，再追加问号，然后再向params中添加一与问号对应的值
    			 */
    			whereSql.append(" and ").append(expr.getName())
    				.append(" ").append(expr.getOperator()).append(" ");
    			// where 1=1 and bid = ?
    			if(!expr.getOperator().equals("is null")) {
    				whereSql.append("?");
    				params.add(expr.getValue());
    			}
    		}
    
    		/*
    		 * 3. 总记录数 
    		 */
    		String sql = "select count(*) from t_book" + whereSql;
    		Number number = (Number)qr.query(sql, new ScalarHandler(), params.toArray());
    		int tr = number.intValue();//得到了总记录数
    		/*
    		 * 4. 得到beanList，即当前页记录
    		 */
    		sql = "select * from t_book" + whereSql + " order by orderBy limit ?,?";
    		params.add((pc-1) * ps);//当前页首行记录的下标
    		params.add(ps);//一共查询几行，就是每页记录数
    		
    		List<Book> beanList = qr.query(sql, new BeanListHandler<Book>(Book.class), 
    				params.toArray());
    		
    		/*
    		 * 5. 创建PageBean，设置参数
    		 */
    		PageBean<Book> pb = new PageBean<Book>();
    		/*
    		 * 其中PageBean没有url，这个任务由Servlet完成
    		 */
    		pb.setBeanList(beanList);
    		pb.setPc(pc);
    		pb.setPs(ps);
    		pb.setTr(tr);
    		
    		return pb;
    	}
    	
    	
    }

4.service层的实现

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1.  package com.page.book.service;
2.  
3.  import java.sql.SQLException;
4.  
5.  import com.page.book.dao.BookDao;
6.  import com.page.book.domain.Book;
7.  import com.page.pager.PageBean;
8.  
9.  public class BookService \{
10. private BookDao bookDao = new BookDao();
11. 
12. /\*\*
13.  \* 按分类查
14.  \* @param cid
15.  \* @param pc
16.  \* @return
17.  \*/
18. public PageBean<Book> findByCategory(String cid, int pc) \{
19. try \{
20. return bookDao.findByCategory(cid, pc);
21. \} catch (SQLException e) \{
22. throw new RuntimeException(e);
23. \}
24. \}
25. 
26. \}

![save_snippets.png][]

package com.page.book.service;
    
    import java.sql.SQLException;
    
    import com.page.book.dao.BookDao;
    import com.page.book.domain.Book;
    import com.page.pager.PageBean;
    
    public class BookService {
    	private BookDao bookDao = new BookDao();
    	
    	/**
    	 * 按分类查
    	 * @param cid
    	 * @param pc
    	 * @return
    	 */
    	public PageBean<Book> findByCategory(String cid, int pc) {
    		try {
    			return bookDao.findByCategory(cid, pc);
    		} catch (SQLException e) {
    			throw new RuntimeException(e);
    		}
    	}
    	
    }

5.servlet的实现

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1.  package com.page.book.servlet;
2.  
3.  import java.io.IOException;
4.  
5.  import javax.servlet.ServletException;
6.  import javax.servlet.http.HttpServletRequest;
7.  import javax.servlet.http.HttpServletResponse;
8.  
9.  import cn.itcast.servlet.BaseServlet;
10. 
11. import com.page.book.domain.Book;
12. import com.page.book.service.BookService;
13. import com.page.pager.PageBean;
14. 
15. public class BookServlet extends BaseServlet \{
16. /\*\*
17.  \* 
18.  \*/
19. private static final long serialVersionUID = 1L;
20. private BookService bookService = new BookService();
21. 
22. /\*\*
23.  \* 获取当前页码
24.  \* @param req
25.  \* @return
26.  \*/
27. private int getPc(HttpServletRequest req) \{
28. int pc = 1;
29. String param = req.getParameter("pc");
30. if(param != null && !param.trim().isEmpty()) \{
31. try \{
32. pc = Integer.parseInt(param);
33. \} catch(RuntimeException e) \{\}
34. \}
35. return pc;
36. \}
37. 
38. /\*\*
39.  \* 截取url，页面中的分页导航中需要使用它做为超链接的目标！
40.  \* @param req
41.  \* @return
42.  \*/
43. /\*
44.  \* http://localhost:8080/goods/BookServlet?methed=findByCategory&cid=xxx&pc=3
45.  \* /goods/BookServlet + methed=findByCategory&cid=xxx&pc=3
46.  \*/
47. private String getUrl(HttpServletRequest req) \{
48. 
49. String url = req.getRequestURI() + "?" \+ req.getQueryString();
50. System.out.println("url:"\+url);
51. /\*
52.  \* 如果url中存在pc参数，截取掉，如果不存在那就不用截取。
53.  \*/
54. int index = url.lastIndexOf("&pc=");
55. if(index != -1) \{
56. url = url.substring(0, index);
57. \}
58. return url;
59. \}
60. 
61. public String findByCategory(HttpServletRequest req, HttpServletResponse resp)throws ServletException, IOException \{
62. /\*
63.  \* 1. 得到pc：如果页面传递，使用页面的，如果没传，pc=1
64.  \*/
65. int pc = getPc(req);
66. /\*
67.  \* 2. 得到url：...
68.  \*/
69. String url = getUrl(req);
70. System.out.println("url----"\+url);
71. /\*
72.  \* 3. 获取查询条件，本方法就是cid，即分类的id
73.  \*/
74. String cid = req.getParameter("cid");
75. /\*
76.  \* 4. 使用pc和cid调用service\#findByCategory得到PageBean
77.  \*/
78. PageBean<Book> pb = bookService.findByCategory(cid, pc);
79. /\*
80.  \* 5. 给PageBean设置url，保存PageBean，转发到/jsps/book/list.jsp
81.  \*/
82. pb.setUrl(url);
83. req.setAttribute("pb", pb);
84. return "f:/pager/pager.jsp";//f代表转发
85. \}
86. \}

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package com.page.book.servlet;
    
    import java.io.IOException;
    
    import javax.servlet.ServletException;
    import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpServletResponse;
    
    import cn.itcast.servlet.BaseServlet;
    
    import com.page.book.domain.Book;
    import com.page.book.service.BookService;
    import com.page.pager.PageBean;
    
    public class BookServlet extends BaseServlet {
    	/**
    	 * 
    	 */
    	private static final long serialVersionUID = 1L;
    	private BookService bookService = new BookService();
    	
    	/**
    	 * 获取当前页码
    	 * @param req
    	 * @return
    	 */
    	private int getPc(HttpServletRequest req) {
    		int pc = 1;
    		String param = req.getParameter("pc");
    		if(param != null && !param.trim().isEmpty()) {
    			try {
    				pc = Integer.parseInt(param);
    			} catch(RuntimeException e) {}
    		}
    		return pc;
    	}
    	
    	/**
    	 * 截取url，页面中的分页导航中需要使用它做为超链接的目标！
    	 * @param req
    	 * @return
    	 */
    	/*
    	 * http://localhost:8080/goods/BookServlet?methed=findByCategory&cid=xxx&pc=3
    	 * /goods/BookServlet + methed=findByCategory&cid=xxx&pc=3
    	 */
    	private String getUrl(HttpServletRequest req) {
    		
    		String url = req.getRequestURI() + "?" + req.getQueryString();
    		System.out.println("url:"+url);
    		/*
    		 * 如果url中存在pc参数，截取掉，如果不存在那就不用截取。
    		 */
    		int index = url.lastIndexOf("&pc=");
    		if(index != -1) {
    			url = url.substring(0, index);
    		}
    		return url;
    	}
    	
    	public String findByCategory(HttpServletRequest req, HttpServletResponse resp)throws ServletException, IOException {
    		/*
    		 * 1. 得到pc：如果页面传递，使用页面的，如果没传，pc=1
    		 */
    		int pc = getPc(req);
    		/*
    		 * 2. 得到url：...
    		 */
    		String url = getUrl(req);
    		System.out.println("url----"+url);
    		/*
    		 * 3. 获取查询条件，本方法就是cid，即分类的id
    		 */
    		String cid = req.getParameter("cid");
    		/*
    		 * 4. 使用pc和cid调用service#findByCategory得到PageBean
    		 */
    		PageBean<Book> pb = bookService.findByCategory(cid, pc);
    		/*
    		 * 5. 给PageBean设置url，保存PageBean，转发到/jsps/book/list.jsp
    		 */
    		pb.setUrl(url);
    		req.setAttribute("pb", pb);
    		return "f:/pager/pager.jsp";//f代表转发
    	}
    }

6.关于分页的相关类的实现

**\[java\]**  view plain  copy

print ?

1.  package com.page.pager;
2.  
3.  public class PageConstants \{
4.  public static final int BOOK\_PAGE\_SIZE = 12;//图书每页记录数
5.  \}

![save_snippets.png][]

package com.page.pager;
    
    public class PageConstants {
    	public static final int BOOK_PAGE_SIZE = 12;//图书每页记录数
    }

7.pageBean的实现

**\[java\]**  view plain  copy

print ?

1.  package com.page.pager;
2.  
3.  import java.util.List;
4.  
5.  /\*\*
6.   \* 分页Bean，它会在各层之间传递
7.   \*
8.   \* @param <T>
9.   \*/
10. public class PageBean<T> \{
11. private int pc;//当前页码
12. private int tr;//总记录数
13. private int ps;//每页记录数
14. private String url;//请求路径和参数，例如BookServlet?method=findXXX&cid=1&bname=2
15. private List<T> beanList;
16. 
17. // 计算总页数
18. public int getTp() \{
19. int tp = tr / ps;
20. return tr % ps == 0 ? tp : tp + 1;
21. \}
22. 
23. public int getPc() \{
24. return pc;
25. \}
26. public void setPc(int pc) \{
27. this.pc = pc;
28. \}
29. public int getTr() \{
30. return tr;
31. \}
32. public void setTr(int tr) \{
33. this.tr = tr;
34. \}
35. public int getPs() \{
36. return ps;
37. \}
38. public void setPs(int ps) \{
39. this.ps = ps;
40. \}
41. public String getUrl() \{
42. return url;
43. \}
44. public void setUrl(String url) \{
45. this.url = url;
46. \}
47. public List<T> getBeanList() \{
48. return beanList;
49. \}
50. public void setBeanList(List<T> beanList) \{
51. this.beanList = beanList;
52. \}
53. \}

![save_snippets.png][]

package com.page.pager;
    
    import java.util.List;
    
    /**
     * 分页Bean，它会在各层之间传递
     *
     * @param <T>
     */
    public class PageBean<T> {
    	private int pc;//当前页码
    	private int tr;//总记录数
    	private int ps;//每页记录数
    	private String url;//请求路径和参数，例如BookServlet?method=findXXX&cid=1&bname=2
    	private List<T> beanList;
    	
    	// 计算总页数
    	public int getTp() {
    		int tp = tr / ps;
    		return tr % ps == 0 ? tp : tp + 1;
    	}
    	
    	public int getPc() {
    		return pc;
    	}
    	public void setPc(int pc) {
    		this.pc = pc;
    	}
    	public int getTr() {
    		return tr;
    	}
    	public void setTr(int tr) {
    		this.tr = tr;
    	}
    	public int getPs() {
    		return ps;
    	}
    	public void setPs(int ps) {
    		this.ps = ps;
    	}
    	public String getUrl() {
    		return url;
    	}
    	public void setUrl(String url) {
    		this.url = url;
    	}
    	public List<T> getBeanList() {
    		return beanList;
    	}
    	public void setBeanList(List<T> beanList) {
    		this.beanList = beanList;
    	}
    }

8.数据库辅助类

**\[java\]**  view plain  copy

print ?

1.  package com.page.pager;
2.  
3.  public class Expression \{
4.  private String name;
5.  private String operator;
6.  private String value;
7.  public String getName() \{
8.  return name;
9.  \}
10. public void setName(String name) \{
11. this.name = name;
12. \}
13. public String getOperator() \{
14. return operator;
15. \}
16. public void setOperator(String operator) \{
17. this.operator = operator;
18. \}
19. public String getValue() \{
20. return value;
21. \}
22. public void setValue(String value) \{
23. this.value = value;
24. \}
25. @Override
26. public String toString() \{
27. return "Expression \[name=" \+ name + ", operator=" \+ operator
28. \+ ", value=" \+ value + "\]";
29. \}
30. public Expression() \{
31. super();
32. // TODO Auto-generated constructor stub
33. \}
34. public Expression(String name, String operator, String value) \{
35. super();
36. this.name = name;
37. this.operator = operator;
38. this.value = value;
39. toString();
40. \}
41. 
42. 
43. \}

![save_snippets.png][]

package com.page.pager;
    
    public class Expression {
    	private String name;
    	private String operator;
    	private String value;
    	public String getName() {
    		return name;
    	}
    	public void setName(String name) {
    		this.name = name;
    	}
    	public String getOperator() {
    		return operator;
    	}
    	public void setOperator(String operator) {
    		this.operator = operator;
    	}
    	public String getValue() {
    		return value;
    	}
    	public void setValue(String value) {
    		this.value = value;
    	}
    	@Override
    	public String toString() {
    		return "Expression [name=" + name + ", operator=" + operator
    				+ ", value=" + value + "]";
    	}
    	public Expression() {
    		super();
    		// TODO Auto-generated constructor stub
    	}
    	public Expression(String name, String operator, String value) {
    		super();
    		this.name = name;
    		this.operator = operator;
    		this.value = value;
    		toString();
    	}
    	
    	
    }

9.c3p0文件的配置

**\[html\]**  view plain  copy

print ?

1.  <?xml version="1.0" encoding="UTF-8" ?>
2.  <c3p0-config>
3.  <default-config>
4.  <property name="jdbcUrl">
5.  <!\[CDATA\[
6.   jdbc:mysql://localhost:3306/goods?useUnicode=true&characterEncoding=UTF8&useServerPrepStmts=true&prepStmtCacheSqlLimit=256&cachePrepStmts=true&prepStmtCacheSize=256&rewriteBatchedStatements=true
7.   \]\]>
8.  </property>
9.  <property name="driverClass">com.mysql.jdbc.Driver</property>
10. <property name="user">root</property>
11. <property name="password">906363842aq</property>
12. 
13. <property name="acquireIncrement">3</property>
14. <property name="initialPoolSize">10</property>
15. <property name="minPoolSize">2</property>
16. <property name="maxPoolSize">10</property>
17. </default-config>
18. </c3p0-config>

![save_snippets.png][]

<?xml version="1.0" encoding="UTF-8" ?>
    <c3p0-config>
    	<default-config> 
    		<property name="jdbcUrl">
    			<![CDATA[
    				jdbc:mysql://localhost:3306/goods?useUnicode=true&characterEncoding=UTF8&useServerPrepStmts=true&prepStmtCacheSqlLimit=256&cachePrepStmts=true&prepStmtCacheSize=256&rewriteBatchedStatements=true
    			]]>
    		</property>
    		<property name="driverClass">com.mysql.jdbc.Driver</property>
    		<property name="user">root</property>
    		<property name="password">906363842aq</property>
    		
    		<property name="acquireIncrement">3</property>
    		<property name="initialPoolSize">10</property>
    		<property name="minPoolSize">2</property>
    		<property name="maxPoolSize">10</property>
    	</default-config>
    </c3p0-config>

10.分页前端的操作

**\[html\]**  view plain  copy

print ?

1.  <%@ page language="java" import="java.util.\*" pageEncoding="UTF-8"%>
2.  <%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
3.  <link rel="stylesheet" type="text/css" href="<c:url value='/pager/pager.css'/>" />
4.  <script type="text/javascript" src="<c:url value='/pager/jquery-1.5.1.js'/>"></script>
5.  <script type="text/javascript">
6.  function \_go() \{
7.  var pc = $("\#pageCode").val();//获取文本框中的当前页码
8.  if(!/^\[1-9\]\\d\*$/.test(pc)) \{//对当前页码进行整数校验
9.  alert('请输入正确的页码！');
10. return;
11. \}
12. if(pc > $\{pb.tp\}) \{//判断当前页码是否大于最大页
13. alert('请输入正确的页码！');
14. return;
15. \}
16. location = "$\{pb.url\}&pc=" \+ pc;
17. \}
18. </script>
19. <table border="1">
20. <tr>
21. <th>书名</th>
22. <th>书价</th>
23. <th>折扣</th>
24. <th>作者</th>
25. <th>出版社</th>
26. <th>出版时间</th>
27. </tr>
28. <c:forEach items="$\{pb.beanList \}" var="book">
29. 
30. <tr>
31. <td>$\{book.bname \}</td>
32. <td>$\{book.price \}</td>
33. <td>$\{book.discount \}折</td>
34. <td>$\{book.author \}</td>
35. <td>$\{book.press \}</td>
36. <td>$\{book.publishtime \}</td>
37. </tr>
38. </c:forEach>
39. </table>
40. 
41. 
42. <div class="divBody">
43. <div class="divContent">
44. <%--上一页 --%>
45. <c:choose>
46. <c:when test="$\{pb.pc eq 1 \}"><span class="spanBtnDisabled">上一页</span></c:when>
47. <c:otherwise><a href="$\{pb.url \}&pc=$\{pb.pc-1\}" class="aBtn bold">上一页</a></c:otherwise>
48. </c:choose>
49. 
50. 
51. 
52. <%--我们需要计算页码列表的开始和结束位置，即两个变量begin和end
53. 计算它们需要通过当前页码！
54. 1. 总页数不足6页--> begin=1, end=最大页
55. 2. 通过公式设置begin和end，begin=当前页-1，end=当前页+3
56. 3. 如果begin<1，那么让begin=1，end=6
57. 4. 如果end>tp, 让begin=tp\-5, end=tp
58. \--%>
59. <c:choose>
60. <c:when test="$\{pb.tp <= 6 \}">
61. <c:set var="begin" value="1"/>
62. <c:set var="end" value="$\{pb.tp \}"/>
63. </c:when>
64. <c:otherwise>
65. <c:set var="begin" value="$\{pb.pc-2 \}"/>
66. <c:set var="end" value="$\{pb.pc + 3\}"/>
67. <c:if test="$\{begin < 1 \}">
68. <c:set var="begin" value="1"/>
69. <c:set var="end" value="6"/>
70. </c:if>
71. <c:if test="$\{end > pb.tp \}">
72. <c:set var="begin" value="$\{pb.tp-5 \}"/>
73. <c:set var="end" value="$\{pb.tp \}"/>
74. </c:if>
75. </c:otherwise>
76. </c:choose>
77. 
78. <c:forEach begin="$\{begin \}" end="$\{end \}" var="i">
79. <c:choose>
80. <c:when test="$\{i eq pb.pc \}">
81. <span class="spanBtnSelect">$\{i \}</span>
82. </c:when>
83. <c:otherwise>
84. <a href="$\{pb.url \}&pc=$\{i\}" class="aBtn">$\{i \}</a>
85. </c:otherwise>
86. </c:choose>
87. 
88. 
89. </c:forEach>
90. <%-- 计算begin和end --%>
91. <%-- 如果总页数<=6，那么显示所有页码，即begin=1 end=$\{pb.tp\} --%>
92. <%-- 设置begin=当前页码-2，end=当前页码+3 --%>
93. <%-- 如果begin<1，那么让begin=1 end=6 \--%>
94. <%-- 如果end>最大页，那么begin=最大页-5 end=最大页 --%>
95. 
96. 
97. 
98. <%-- 显示点点点 --%>
99. <c:if test="$\{end < pb.tp \}">
100. <span class="spanApostrophe">...</span>
101. </c:if>
102. 
103. 
104. <%--下一页 --%>
105. <c:choose>
106. <c:when test="$\{pb.pc eq pb.tp \}"><span class="spanBtnDisabled">下一页</span></c:when>
107. <c:otherwise><a href="$\{pb.url \}&pc=$\{pb.pc+1\}" class="aBtn bold">下一页</a></c:otherwise>
108. </c:choose>
109. 
110. 
111. 
112. 
113. <%-- 共N页 到M页 --%>
114. <span>共$\{pb.tp \}页</span>
115. <span>到</span>
116. <input type="text" class="inputPageCode" id="pageCode" value="$\{pb.pc \}"/>
117. <span>页</span>
118. <a href="javascript:\_go();" class="aSubmit">确定</a>
119. </div>
120. </div>

![save_snippets.png][]

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
    <%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
    	<link rel="stylesheet" type="text/css" href="<c:url value='/pager/pager.css'/>" />
    		<script type="text/javascript" src="<c:url value='/pager/jquery-1.5.1.js'/>"></script>
    <script type="text/javascript">
    	function _go() {
    		var pc = $("#pageCode").val();//获取文本框中的当前页码
    		if(!/^[1-9]\d*$/.test(pc)) {//对当前页码进行整数校验
    			alert('请输入正确的页码！');
    			return;
    		}
    		if(pc > ${pb.tp}) {//判断当前页码是否大于最大页
    			alert('请输入正确的页码！');
    			return;
    		}
    		location = "${pb.url}&pc=" + pc;
    	}
    </script>
    <table border="1">
     <tr>
      <th>书名</th>
      <th>书价</th>
      <th>折扣</th>
      <th>作者</th>
      <th>出版社</th>
      <th>出版时间</th>
      </tr>
      <c:forEach items="${pb.beanList }" var="book">
     
      <tr>
      	<td>${book.bname }</td>
        <td>${book.price }</td>
        <td>${book.discount }折</td>
        <td>${book.author }</td>
        <td>${book.press }</td>
        <td>${book.publishtime }</td>
      </tr>
      </c:forEach>
    </table>
    
    
    <div class="divBody">
      <div class="divContent">
        <%--上一页 --%>
    <c:choose>
    	<c:when test="${pb.pc eq 1 }"><span class="spanBtnDisabled">上一页</span></c:when>
    	<c:otherwise><a href="${pb.url }&pc=${pb.pc-1}" class="aBtn bold">上一页</a></c:otherwise>
    </c:choose>
            
            
    
    <%--我们需要计算页码列表的开始和结束位置，即两个变量begin和end
    计算它们需要通过当前页码！
    1. 总页数不足6页--> begin=1, end=最大页
    2. 通过公式设置begin和end，begin=当前页-1，end=当前页+3
    3. 如果begin<1，那么让begin=1，end=6
    4. 如果end>tp, 让begin=tp-5, end=tp
     --%>
     <c:choose>
     	<c:when test="${pb.tp <= 6 }">
     		<c:set var="begin" value="1"/>
     		<c:set var="end" value="${pb.tp }"/>
     	</c:when>
     	<c:otherwise>
     		<c:set var="begin" value="${pb.pc-2 }"/>
     		<c:set var="end" value="${pb.pc + 3}"/>
     		<c:if test="${begin < 1 }">
     		  <c:set var="begin" value="1"/>
     		  <c:set var="end" value="6"/>
     		</c:if>
     		<c:if test="${end > pb.tp }">
     		  <c:set var="begin" value="${pb.tp-5 }"/>
     		  <c:set var="end" value="${pb.tp }"/>
     		</c:if> 		
     	</c:otherwise>
     </c:choose>
     
     <c:forEach begin="${begin }" end="${end }" var="i">
       <c:choose>
       	  <c:when test="${i eq pb.pc }">
       	    <span class="spanBtnSelect">${i }</span>
       	  </c:when>
       	  <c:otherwise>
       	    <a href="${pb.url }&pc=${i}" class="aBtn">${i }</a>
       	  </c:otherwise>
       </c:choose>
               
              	
     </c:forEach>
        <%-- 计算begin和end --%>
          <%-- 如果总页数<=6，那么显示所有页码，即begin=1 end=${pb.tp} --%>
            <%-- 设置begin=当前页码-2，end=当前页码+3 --%>
              <%-- 如果begin<1，那么让begin=1 end=6 --%>
              <%-- 如果end>最大页，那么begin=最大页-5 end=最大页 --%>
    
    
        
        <%-- 显示点点点 --%>
        <c:if test="${end < pb.tp }">
          <span class="spanApostrophe">...</span>
        </c:if> 
    
        
         <%--下一页 --%>
    <c:choose>
    	<c:when test="${pb.pc eq pb.tp }"><span class="spanBtnDisabled">下一页</span></c:when>
    	<c:otherwise><a href="${pb.url }&pc=${pb.pc+1}" class="aBtn bold">下一页</a></c:otherwise>
    </c:choose>
            
            
              
        
        <%-- 共N页 到M页 --%>
        <span>共${pb.tp }页</span>
        <span>到</span>
        <input type="text" class="inputPageCode" id="pageCode" value="${pb.pc }"/>
        <span>页</span>
        <a href="javascript:_go();" class="aSubmit">确定</a>
      </div>
    </div>

本文转自：http://blog.csdn.net/it\_tingge/article/details/48896983

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