• J2EE基础-自定义MVC(下)

    目录

    一、搭建自定义mvc框架环境

    配置依赖

    框架的配置文件添加、以及web.xml的配置-以后开源框架的使用从这一步开始：

    二、通用增删改查

    三、主界面功能

    一、搭建自定义mvc框架环境

    配置依赖

    将框架打成jar包，然后导入新工程，并且把框架的依赖jar包导入进去

    将我们前面的写的代码打成一个jar包然后导入我们的项目

     

    点击后我们在输入jar，选中java下的第一个选项

     输入要放的地址，点击finish即可

    这样的话我们就可以使用我们上次创建的自定义MVC的框架了，然后我们导入其他的依赖（助手类、baseDao……）

      tag：

    1. package com.oyang.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. 	public 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. }

       BaseDao：

    1. package com.oyang.util;
    2.  
    3. import java.lang.reflect.Field;
    4. import java.sql.Connection;
    5. import java.sql.PreparedStatement;
    6. import java.sql.ResultSet;
    7. import java.util.ArrayList;
    8. import java.util.List;
    9.  
    10. import com.oyang.entity.Book;
    11.  
    12.  
    13. /**
    14.  * T代表的实体类，可以说是Book/User/Goods...
    15.  * @author yang 
    16.  *
    17.  * @date 2022年6月21日下午7:11:08
    18.  */
    19. public class BaseDao<T> {//不知道查什么，就用泛型替代
    20.  
    21. /*	public List<T> executeQuery(String sql,PageBean PageBean,CallBack<T> CallBack) throws Exception {
    22. 		 *//**
    23. 		  * 1.拿到数据库连接
    24. 		  * 2.拿到域定义对象  PreparedStatement
    25. 		  * 3.执行SQL语句
    26. 		  *//*
    27. 		Connection con = DBAccess.getConnection();//重复代码1
    28. 		java.sql.PreparedStatement ps = con.prepareStatement(sql);//重复代码2
    29. 		ResultSet rs=ps.executeQuery();//重复代码3
    30. 		while(rs.next()) {
    31. 			list.add(new Book(rs.getInt("bid"), rs.getString("bname"), rs.getFloat("price")));
    32. 		}
    33. 		//查询不同的表，必然要处理不同的结果集,谁调用谁处理
    34. 		//接口是调用方来实现
    35. 			return CallBack.foreach(rs);
    36. 	}*/
    37. 	
    38. 	//基于调用方组装好的sql语句去做分页：一：对于用户而言，我们要展示第一页第二页第三页的数据，那么对应的limit
    39. 	
    40. 	public List<T> executeQuery(String sql,PageBean PageBean,CallBack<T> CallBack) throws Exception {
    41. 		//SELECT * FROM `t_mvc_book` where bname like '%圣墟%' 
    42. 		//从上面得到select count(1) as y from (SELECT * FROM `t_mvc_book` where bname like '%圣墟%') a;
    43. 		//目的就是为了得到总记录数->得到总页数
    44. 		//SELECT * FROM `t_mvc_book` where bname like '%圣墟%'  limit 10,10;
    45. 		/**
    46. 		  * 1.拿到数据库连接
    47. 		  * 2.拿到域定义对象  PreparedStatement
    48. 		  * 3.执行SQL语句
    49. 		  */
    50. 		Connection con = null;//重复代码1
    51. 		java.sql.PreparedStatement ps = null;//重复代码2
    52. 		ResultSet rs=null;//重复代码3
    53. 		if(PageBean!=null&&PageBean.isPagination()) {//分页时
    54. 			String countSQL=getCountSQL(sql);
    55. 			 con=DBAccess.getConnection();//重复代码1
    56. 			 ps=con.prepareStatement(countSQL);//重复代码2
    57. 			 rs= ps.executeQuery();//重复代码3
    58. 			 if(rs.next()) {
    59. 				 //当前实体类就包含了总记录数
    60. 				 PageBean .setTotal(rs.getString("y"));
    61. 			 }
    62. 			 String pageSQL=getpageSQL(sql,PageBean);
    63. 			 con=DBAccess.getConnection();//重复代码1
    64. 			 ps=con.prepareStatement(pageSQL);//重复代码2
    65. 			 rs= ps.executeQuery();//重复代码3
    66. 		}else {// 不分页
    67. 			 con=DBAccess.getConnection();//重复代码1
    68. 			 ps=con.prepareStatement(sql);//重复代码2
    69. 			 rs= ps.executeQuery();//重复代码3
    70. 		}
    71. 		return CallBack.foreach(rs);
    72. 	}
    73.  
    74. 		/**
    75. 		 * 拼装第N页的数据的SQL
    76. 		 * @param sql 
    77. 		 * @return 
    78. 		 */
    79. 		private String getpageSQL(String sql, PageBean pageBean) {
    80. 			// TODO Auto-generated method stub
    81. 			return sql+" limit "+pageBean.getStartIndex() + ","+pageBean.getRows();
    82. 		}
    83.  
    84.  
    85. 		/**
    86. 		 * 拼装符合条件总记录数的sql
    87. 		 * @param sql
    88. 		 * @param pageBean
    89. 		 * @return
    90. 		 */
    91. 		private String getCountSQL(String sql) {
    92. 			// TODO Auto-generated method stub
    93. 			return "select count(1) as y from ("+sql+") t ";
    94. 		}
    95. 		
    96. 		public int executeUpdate(String sql, T t,String[] attrs) throws Exception {
    97. 			Connection con = DBAccess.getConnection();
    98. 			PreparedStatement ps = con.prepareStatement(sql);
    99. 			//将T的某一个属性对应的值加到ps对象中
    100. 			for (int i = 0; i < attrs.length; i++) {
    101. 				Field f = t.getClass().getDeclaredField(attrs[i]);
    102. 				f.setAccessible(true);
    103. 				ps.setObject(i+1, f.get(t));
    104. 			}
    105. //			ps.setObject(i, book.getBname());
    106. //			ps.setObject(i, book.getPrice());
    107. 			return ps.executeUpdate();
    108. 		}
    109.  
    110. }

     CallBack<T>:

    1. package com.oyang.util;
    2.  
    3. import java.sql.ResultSet;
    4. import java.util.List;
    5.  
    6. /**
    7.  * 回调函数接口类的作用？
    8.  * 谁调用谁处理
    9.  * 
    10.  * @author yang 
    11.  *
    12.  * @date 2022年6月21日下午8:13:46
    13.  */
    14. public interface CallBack<T> {
    15. 	
    16. 	List<T> foreach(ResultSet rs);
    17. 	
    18. }

    DBAccess :

    1. package com.oyang.util;
    2.  
    3. import java.io.InputStream;
    4. import java.sql.Connection;
    5. import java.sql.DriverManager;
    6. import java.sql.ResultSet;
    7. import java.sql.SQLException;
    8. import java.sql.Statement;
    9. import java.util.Properties;
    10.  
    11. /**
    12.  * 提供了一组获得或关闭数据库对象的方法
    13.  * 
    14.  */
    15. public class DBAccess {
    16. 	private static String driver;
    17. 	private static String url;
    18. 	private static String user;
    19. 	private static String password;
    20.  
    21. 	static {// 静态块执行一次，加载 驱动一次
    22. 		try {
    23. 			InputStream is = DBAccess.class
    24. 					.getResourceAsStream("config.properties");
    25.  
    26. 			Properties properties = new Properties();
    27. 			properties.load(is);
    28.  
    29. 			driver = properties.getProperty("driver");
    30. 			url = properties.getProperty("url");
    31. 			user = properties.getProperty("user");
    32. 			password = properties.getProperty("pwd");
    33.  
    34. 			Class.forName(driver);
    35. 		} catch (Exception e) {
    36. 			e.printStackTrace();
    37. 			throw new RuntimeException(e);
    38. 		}
    39. 	}
    40.  
    41. 	/**
    42. 	 * 获得数据连接对象
    43. 	 * 
    44. 	 * @return
    45. 	 */
    46. 	public static Connection getConnection() {
    47. 		try {
    48. 			Connection conn = DriverManager.getConnection(url, user, password);
    49. 			return conn;
    50. 		} catch (SQLException e) {
    51. 			e.printStackTrace();
    52. 			throw new RuntimeException(e);
    53. 		}
    54. 	}
    55.  
    56. 	public static void close(ResultSet rs) {
    57. 		if (null != rs) {
    58. 			try {
    59. 				rs.close();
    60. 			} catch (SQLException e) {
    61. 				e.printStackTrace();
    62. 				throw new RuntimeException(e);
    63. 			}
    64. 		}
    65. 	}
    66.  
    67. 	public static void close(Statement stmt) {
    68. 		if (null != stmt) {
    69. 			try {
    70. 				stmt.close();
    71. 			} catch (SQLException e) {
    72. 				e.printStackTrace();
    73. 				throw new RuntimeException(e);
    74. 			}
    75. 		}
    76. 	}
    77.  
    78. 	public static void close(Connection conn) {
    79. 		if (null != conn) {
    80. 			try {
    81. 				conn.close();
    82. 			} catch (SQLException e) {
    83. 				e.printStackTrace();
    84. 				throw new RuntimeException(e);
    85. 			}
    86. 		}
    87. 	}
    88.  
    89. 	public static void close(Connection conn, Statement stmt, ResultSet rs) {
    90. 		close(rs);
    91. 		close(stmt);
    92. 		close(conn);
    93. 	}
    94.  
    95. 	public static boolean isOracle() {
    96. 		return "oracle.jdbc.driver.OracleDriver".equals(driver);
    97. 	}
    98.  
    99. 	public static boolean isSQLServer() {
    100. 		return "com.microsoft.sqlserver.jdbc.SQLServerDriver".equals(driver);
    101. 	}
    102. 	
    103. 	public static boolean isMysql() {
    104. 		return "com.mysql.cj.jdbc.Driver".equals(driver);
    105. 	}
    106.  
    107. 	public static void main(String[] args) {
    108. 		Connection conn = DBAccess.getConnection();
    109. 		System.out.println(conn);
    110. 		DBAccess.close(conn);
    111. 		System.out.println("isOracle：" + isOracle());
    112. 		System.out.println("isSQLServer：" + isSQLServer());
    113. 		System.out.println("isMysql：" + isMysql());
    114. 		System.out.println("数据库连接(关闭)成功");
    115. 	}
    116. }

    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("*.action")
    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. }

    pageBean实体：

    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 setRequest(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. }

    StringUtils： 

    1. package com.oyang.util;
    2.  
    3. public class StringUtils {
    4. 	// 私有的构造方法，保护此类不能在外部实例化
    5. 	private StringUtils() {
    6. 	}
    7.  
    8. 	/**
    9. 	 * 如果字符串等于null或去空格后等于""，则返回true，否则返回false
    10. 	 * 
    11. 	 * @param s
    12. 	 * @return
    13. 	 */
    14. 	public static boolean isBlank(String s) {
    15. 		boolean b = false;
    16. 		if (null == s || s.trim().equals("")) {
    17. 			b = true;
    18. 		}
    19. 		return b;
    20. 	}
    21. 	
    22. 	/**
    23. 	 * 如果字符串不等于null或去空格后不等于""，则返回true，否则返回false
    24. 	 * 
    25. 	 * @param s
    26. 	 * @return
    27. 	 */
    28. 	public static boolean isNotBlank(String s) {
    29. 		return !isBlank(s);
    30. 	}
    31.  
    32. }

    oyang.tad:

    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.oyang.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>

    框架的配置文件添加、以及web.xml的配置-以后开源框架的使用从这一步开始：

    web.xml:

    1. <?xml version="1.0" encoding="UTF-8"?>
    2. <web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://xmlns.jcp.org/xml/ns/javaee" xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd" id="WebApp_ID" version="3.1">
    3.   <display-name>Oyang_mvc_crud</display-name>
    4.   <servlet>
    5.   	<servlet-name>mvc</servlet-name>
    6.   	<servlet-class>com.oyang.framework.DispatcherServlet</servlet-class>
    7. 	<init-param><!-- 可以把值传到 configLocation中-->
    8. 		<param-name>configLocation</param-name>
    9. 		<param-value>/oyang.xml</param-value>
    10. 	</init-param>
    11.   </servlet>
    12.   
    13.   <servlet-mapping>
    14.   	<servlet-name>mvc</servlet-name>
    15.   	<url-pattern>*.action</url-pattern>
    16.   </servlet-mapping>
    17. </web-app>

    二、通用增删改查

     实体类一Book为例：

    1. package com.oyang.entity;
    2.  
    3. public class Book {
    4. 	private int bid;
    5. 	private String bname;
    6. 	private float price;
    7. 	public int getBid() {
    8. 		return bid;
    9. 	}
    10. 	public void setBid(int bid) {
    11. 		this.bid = bid;
    12. 	}
    13. 	public String getBname() {
    14. 		return bname;
    15. 	}
    16. 	public void setBname(String bname) {
    17. 		this.bname = bname;
    18. 	}
    19. 	public float getPrice() {
    20. 		return price;
    21. 	}
    22. 	public void setPrice(float price) {
    23. 		this.price = price;
    24. 	}
    25. 	public Book() {
    26. 		// TODO Auto-generated constructor stub
    27. 	}
    28. 	public Book(int bid, String bname, float price) {
    29. 		super();
    30. 		this.bid = bid;
    31. 		this.bname = bname;
    32. 		this.price = price;
    33. 	}
    34. 	@Override
    35. 	public String toString() {
    36. 		return "Book [bid=" + bid + ", bname=" + bname + ", price=" + price + "]";
    37. 	}
    38. 	
    39. }

    Dao方法：

    1. package com.oyang.dao;
    2.  
    3. import java.sql.Connection;
    4. import java.sql.PreparedStatement;
    5. import java.sql.SQLException;
    6. import java.util.ArrayList;
    7. import java.util.List;
    8.  
    9. import com.oyang.entity.Book;
    10. import com.oyang.util.BaseDao;
    11. import com.oyang.util.DBAccess;
    12. import com.oyang.util.PageBean;
    13. import com.oyang.util.StringUtils;
    14.  
    15. public class BookDao extends BaseDao<Book>{
    16. 	
    17.  
    18. 	//查询
    19. 	public List<Book> list(Book book,PageBean pageBean) throws Exception{
    20. 		String sql=" select * from t_mvc_book where 1=1 ";
    21. 		String bname=book.getBname();
    22. 		if(StringUtils.isNotBlank(bname)) {
    23. 			sql+=" and bname like '%"+bname+"%' ";
    24. 		}
    25. 		int bid=book.getBid();
    26. 		//前台jsp传递到后台，只要传了就有值,没传就是默认值'0'
    27. 		if(bid!=0) {
    28. 			sql+=" and bid="+bid;
    29. 		}
    30. 		return super.executeQuery(sql, pageBean, rs ->{
    31. 			List<Book> list=new ArrayList<>();
    32. 			try {
    33. 				while(rs.next()) {
    34. 					list.add(new Book(rs.getInt("bid"), rs.getString("bname"), rs.getFloat("price")));
    35. 				}
    36. 			} catch (Exception e) {
    37. 				// TODO Auto-generated catch block
    38. 				e.printStackTrace();
    39. 			}
    40. 			return list;
    41. 		});
    42. 	}
    43. 	
    44. 	//增
    45. 	/*public int add(Book book) throws Exception {
    46. 		Connection con = DBAccess.getConnection();
    47. 		String sql=" insert into t_mvc_book values(?,?,?)";
    48. 		PreparedStatement ps = con.prepareStatement(sql);
    49. 		ps.setObject(1, book.getBid());
    50. 		ps.setObject(2, book.getBname());
    51. 		ps.setObject(3, book.getPrice());
    52. 		return ps.executeUpdate();
    53. 	}*/
    54. 	public int add(Book book) throws Exception {
    55. 		String sql=" insert into t_mvc_book values(?,?,?)";
    56. 		return super.executeUpdate(sql, book,new String[] {"bid","bname","price"});
    57. 	}
    58. 	
    59. 	//删
    60. 	public int del(Book book) throws Exception {
    61. 		String sql=" delete from t_mvc_book where bid=?";
    62. 		return super.executeUpdate(sql, book, new String [] {"bid"});
    63. 	}
    64. 	
    65. 	
    66. 	//改
    67. 	/*public int edit(Book book) throws Exception {
    68. 		Connection con = DBAccess.getConnection();
    69. 		String sql=" update t_mvc_book set  bname=?,price=? where bid=?";
    70. 		PreparedStatement ps = con.prepareStatement(sql);
    71. 		ps.setObject(1, book.getBname());
    72. 		ps.setObject(2, book.getPrice());
    73. 		ps.setObject(3, book.getBid());
    74. 		return ps.executeUpdate();
    75. 	}*/
    76. 	public int edit(Book book) throws Exception {
    77. 		String sql=" update t_mvc_book set  bname=?,price=? where bid=?";
    78. 		return super.executeUpdate(sql, book, new String [] {"bname","price","bid"});
    79. 	}
    80. }

    BookAction：

    1. package com.oyang.web;
    2.  
    3. import java.util.List;
    4.  
    5. import javax.servlet.http.HttpServletRequest;
    6. import javax.servlet.http.HttpServletResponse;
    7.  
    8. import com.oyang.dao.BookDao;
    9. import com.oyang.entity.Book;
    10. import com.oyang.util.PageBean;
    11. import com.oyang.framework.ActionSupport;
    12. import com.oyang.framework.ModelDriven;
    13. //用到模型驱动接口，作用就是能够帮我快速的封装前台传递过来的参数
    14. public class BookAction extends ActionSupport implements ModelDriven<Book>{
    15. 	
    16. 	private Book book=new Book();
    17. 	private BookDao b=new BookDao();
    18. 	
    19. 	@Override
    20. 	public Book getModel() {
    21. 		return book;
    22. 	}
    23. 	
    24. 	//增加
    25. 	public String add(HttpServletRequest request, HttpServletResponse response) throws Exception {
    26. 		b.add(book);
    27. 		//toList代表跳到查询界面
    28. 		return "tolist";
    29. 	}
    30. 	
    31. 	//删
    32. 	public String del(HttpServletRequest request, HttpServletResponse response) {
    33. 		try {
    34. 			b.del(book);
    35. 		} catch (Exception e) {
    36. 			e.printStackTrace();
    37. 		}
    38. 		//toList代表跳到查询界面
    39. 		return "tolist";
    40. 	}
    41. 	
    42. 	//改
    43. 		public String edit(HttpServletRequest request, HttpServletResponse response) {
    44. 			try {
    45. 				b.edit(book);
    46. 			} catch (Exception e) {
    47. 				e.printStackTrace();
    48. 			}
    49. 			//toList代表跳到查询界面
    50. 			return "tolist";
    51. 		}
    52. 	
    53. 		//查
    54. 		public String list(HttpServletRequest request, HttpServletResponse response) {
    55. 			try {
    56. 				PageBean pageBean = new PageBean();
    57. 				pageBean.setRequest(request);
    58. 				List<Book> list=b.list(book, pageBean);
    59. 				request.setAttribute("list", list);
    60. 				request.setAttribute("pageBean", pageBean);
    61. 			} catch (Exception e) {
    62. 				e.printStackTrace();
    63. 			}
    64. 			//执行查询展示
    65. 			return "list";
    66. 		}
    67. 		
    68. 	//跳转到新增/修改界面	
    69. 		public String preEdit(HttpServletRequest request, HttpServletResponse response) {
    70. 			try {
    71. 				int bid = book.getBid();
    72. 				if(bid!=0) {
    73. 					//传递bid到后台，有且只能查询一条数据，那也就意味着list集合中只有一条
    74. 					List<Book> list = b.list(book, null);
    75. 					request.setAttribute("b", list.get(0));
    76. 				}
    77. 			} catch (Exception e) {
    78. 				e.printStackTrace();
    79. 			}
    80. 			//toList代表跳到编辑界面
    81. 			return "toEdit";
    82. 		}
    83. }

    三、主界面功能

    主界面jsp代码：

    1. <%@ page language="java" contentType="text/html; charset=UTF-8"
    2. 	pageEncoding="UTF-8"%>
    3. <%@taglib uri="https://blog.csdn.net/weixin_65211978?type=blog" prefix="y" %>
    4. <%@taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%>
    5. <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
    6. <html>
    7. <head>
    8. <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
    9. <link
    10. 	href="https://cdn.bootcdn.net/ajax/libs/twitter-bootstrap/4.5.0/css/bootstrap.css"
    11. 	rel="stylesheet">
    12. <script
    13. 	src="https://cdn.bootcdn.net/ajax/libs/twitter-bootstrap/4.5.0/js/bootstrap.js"></script>
    14. <title>书籍列表</title>
    15. <style type="text/css">
    16. .page-item input {
    17. 	padding: 0;
    18. 	width: 40px;
    19. 	height: 100%;
    20. 	text-align: center;
    21. 	margin: 0 6px;
    22. }
    23.  
    24. .page-item input, .page-item b {
    25. 	line-height: 38px;
    26. 	float: left;
    27. 	font-weight: 400;
    28. }
    29.  
    30. .page-item.go-input {
    31. 	margin: 0 10px;
    32. }
    33. </style>
    34. </head>
    35. <body>
    36. 	<form class="form-inline"
    37. 		action="${pageContext.request.contextPath }/book.action?methodName=list" method="post">
    38. 		<div class="form-group mb-2">
    39. 			<input type="text" class="form-control-plaintext" name="bname"
    40. 				placeholder="请输入书籍名称">
    41. 		</div>
    42. 		<button type="submit" class="btn btn-primary mb-2">查询</button>
    43. 		<a href="${pageContext.request.contextPath }/book.action?methodName=preEdit">新增</a>
    44. 	</form>
    45.  
    46. 	<table class="table table-striped ">
    47. 		<thead>
    48. 			<tr>
    49. 				<th scope="col">书籍ID</th>
    50. 				<th scope="col">书籍名</th>
    51. 				<th scope="col">价格</th>
    52. 				<th scope="col">操作</th>
    53. 			</tr>
    54. 		</thead>
    55. 		<tbody>
    56. 		 <c:forEach items="${list}" var="b"> 
    57. 			<tr>
    58. 				<td>${b.bid}</td>
    59. 				<td>${b.bname}</td>
    60. 				<td>${b.price}</td>
    61. 				<td>
    62. 					<a href="${pageContext.request.contextPath }/book.action?methodName=preEdit$bid=${b.bid}">编辑</a>
    63. 					<a href="${pageContext.request.contextPath }/book.action?methodName=del$bid=${b.bid}">删除</a>
    64. 					
    65. 				</td>
    66. 			</tr>
    67. 		</c:forEach>
    68. 		</tbody>
    69. 	</table>
    70. 	
    71. 	<y:page pageBean="${pageBean}"></y:page>
    72.  
    73. </body>
    74. </html>

    效果图：

    查询： 

     

    增加&修改界面：

    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. <form action="${pageContext.request.contextPath }/book.action?methodName=${empty b ? 'add' :'edit'}" method="post">
    11. 	bid:<input type="text" name="bid" value="${b.bid}">
    12. 	bname:<input type="text" name="bname" value="${b.bname}">
    13. 	price:<input type="text" name="price" value="${b.price}">
    14. 	<input type="submit">
    15. </form>
    16. </body>
    17. </html>

     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/125478903