自定义MVC之模糊查询

菲仔yo

于 2022-07-23 16:29:18 发布

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文章标签：数据库 mysql

本文链接：https://blog.youkuaiyun.com/m0_67331668/article/details/125914935

版权

本文详细介绍了如何在自定义的MVC框架中实现数据库的模糊查询功能。从创建项目、添加依赖到配置环境，再到实现接口、编写实体类、控制器和配置文件，每个步骤都有清晰的说明。通过编写测试用例确保查询功能的正确性，并展示了最终的运行效果。

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2.2.1方法接口（IStudentDao）

2.2.2实现接口（StudentDao）

2.2.3 测试

2.2.4 service包中的接口与实现

1.配置环境

1.1创建一个项目

记得勾选下图：

1.2添加jar包

1.3在web.xml中添加过滤器

记得放在跳转页面的上面

 <!-- 过滤器 -->
  <filter>
  	<filter-name>encodingFilter</filter-name>
  	<filter-class>com.zking.mymvc.util.EncodingFiter</filter-class>
  </filter>
  <filter-mapping>
  	<filter-name>encodingFilter</filter-name>
  	<url-pattern>/*</url-pattern>
  </filter-mapping>

<filter-class>com.zking.mymvc.util.EncodingFiter</filter-class>是怎么拿到的？

1.4创建包

2. 方法的实现步骤

2.1创建实体类（Student）

public class Student {
	
	private Integer sid;
	
	private String sname;
	
	private Integer score;
	
	private Integer clazz;
	
	private Integer version;

	public Integer getSid() {
		return sid;
	}

	public void setSid(Integer sid) {
		this.sid = sid;
	}

	public String getSname() {
		return sname;
	}

	public void setSname(String sname) {
		this.sname = sname;
	}

	public Integer getScore() {
		return score;
	}

	public void setScore(Integer score) {
		this.score = score;
	}

	public Integer getClazz() {
		return clazz;
	}

	public void setClazz(Integer clazz) {
		this.clazz = clazz;
	}

	public Integer getVersion() {
		return version;
	}

	public void setVersion(Integer version) {
		this.version = version;
	}

	@Override
	public String toString() {
		return "Student [sid=" + sid + ", sname=" + sname + ", score=" + score + ", clazz=" + clazz + ", version="
				+ version + "]";
	}	

}

2.2模糊查询

2.2.1方法接口（IStudentDao）

public interface IStudentDao {
	
	List<Student> getStudents(Student stu);

}

2.2.2实现接口（StudentDao）

PageBean pageBean是重构后才出现的，相应的方法接口上也会自动出现

public class StudentDao implements IStudentDao {

	@Override
	public List<Student> getStudents(Student stu, PageBean pageBean) {
		String sql = "select sid,sname,score,class,version from t_student";
		
		List<Object> param = new ArrayList<>();
		if(stu != null 
				&& stu.getSname() != null 
				&& !"".equals(stu.getSname())) {
			sql += " where sname like ?";
			param.add(stu.getSname()+"%");
		}
		
		return BaseDao.query(sql, param, pageBean, new ICovent<Student>() {

			@Override
			public List<Student> convent(ResultSet rs) throws SQLException {
				List<Student> list = new ArrayList<>();
				while(rs.next()) {
					Student student = new Student();
					student.setSid(rs.getInt("sid"));
					student.setSname(rs.getString("sname"));
					student.setScore(rs.getInt("score"));
					student.setClazz(rs.getInt("class"));
					student.setVersion(rs.getInt("version"));
					list.add(student);
				}
				return list;
			}
			
		});
	}
}

方法是需要重构的，怎么进行重构呢？

鼠标点击方法然后

点击Yes后

点击Add后进行添加就OK了

2.2.3 测试

测试我们可以添加一个JUnit

点击项目右键

点击添加

点击JUnit

然后再点下一步，不要选3，因为它不支持java注解

然后应用就可以了

测试代码

@Test
public void testGetStudent() {
	Student student = new Student();
	List<Student> list = getStudents(student, new PageBean());
	list.forEach(t->System.out.println(t));
}

效果图

2.2.4 service包中的接口与实现

接口：

public interface IStudentService {
	
	List<Student> getStudents(Student stu, PageBean pageBean);
	
}

实现：

public class StudentService implements IStudentService {
	
	private IStudentDao dao = new StudentDao();

	@Override
	public List<Student> getStudents(Student stu, PageBean pageBean) {
		return dao.getStudents(stu, pageBean);
	}

}

2.2.5编写子控制器

public class StudentAction extends AbstractAction implements ModelDrive{

	private Student student = new Student();
	
	@Override
	public Object getModel() {
		return student;
	}
	
	private IStudentService service = new StudentService();
	
	public String getStudents(HttpServletRequest req,HttpServletResponse resp) {
		//分页查询
		PageBean pageBean = new PageBean();
		pageBean.setRequest(req);
		
		List<Student> students = service.getStudents(student, pageBean);
		req.setAttribute("students", students);
		
		return "students";
	}

}

2.2.6编写config.xml

<config>
	<action path="/studentAction" type="com.pf.mymvcdemo.action.StudentAction">
		<forward name="students" path="/students.jsp" redirect="false"/>
	</action>
	
</config>

2.2.7编写mytag.tld

<!DOCTYPE taglib
  PUBLIC "-//Sun Microsystems, Inc.//DTD JSP Tag Library 1.2//EN"
   "http://java.sun.com/dtd/web-jsptaglibrary_1_2.dtd">
<!-- 标签库描述符 -->
<taglib xmlns="http://java.sun.com/JSP/TagLibraryDescriptor">
	<tlib-version>1.0</tlib-version>
	<jsp-version>1.2</jsp-version>
	<short-name>Simple Tags</short-name>
	<uri>/pf</uri>
	
	<tag>
		<!-- 标签名 -->
		<name>out</name>
		<!-- 标签助手类 -->
		<tag-class>com.pf.mymvc.tag.OutTag</tag-class>
		<!-- 标签的内容类型：empty表示空标签，jsp表示可以为任何合法的JSP元素 -->
		<body-content>empty</body-content>
		<attribute>
			<!-- 属性名， OutTag类中的val属性相匹配 -->
			<name>val</name>
			<!-- 表示该属性为必要的属性 -->
			<required>true</required>
			<!-- 该属性可以接受EL表示式的值 -->
			<rtexprvalue>true</rtexprvalue>
			<!-- 标签描述，用于说明标签的作用 -->
			<description>out标签val属性，用于输出val的值</description>
		</attribute>
		<attribute>
			<name>defaultVal</name>
			<required>false</required>
			<rtexprvalue>false</rtexprvalue>
			<description>用于定义默认值</description>
		</attribute>
	</tag>
	
	<tag>
		<name>if</name>
		<tag-class>com.pf.mymvc.tag.IfTag</tag-class>
		<body-content>jsp</body-content>
		<description>if标签</description>
		<attribute>
			<name>test</name>
			<required>true</required>
			<rtexprvalue>true</rtexprvalue>
		</attribute>
	</tag>
	
	<tag>
		<name>foreach</name>
		<tag-class>com.pf.mymvc.tag.ForeachTag</tag-class>
		<body-content>jsp</body-content>
		<description>foreach标签</description>
		<attribute>
			<name>items</name>
			<required>true</required>
			<rtexprvalue>true</rtexprvalue>
		</attribute>
		<attribute>
			<name>var</name>
			<required>true</required>
			<rtexprvalue>false</rtexprvalue>
		</attribute>
	</tag>
	
	<tag>
		<name>select</name>
		<tag-class>com.pf.mymvc.tag.SelectTag</tag-class>
		<body-content>empty</body-content>
		<attribute>
			<name>id</name>
			<required>true</required>
			<rtexprvalue>false</rtexprvalue>
		</attribute>
		<attribute>
			<name>name</name>
			<required>true</required>
			<rtexprvalue>false</rtexprvalue>
		</attribute>
		<attribute>
			<name>items</name>
			<required>true</required>
			<rtexprvalue>true</rtexprvalue>
		</attribute>
		<attribute>
			<name>cssClass</name>
			<required>false</required>
			<rtexprvalue>false</rtexprvalue>
		</attribute>
		<attribute>
			<name>cssStyle</name>
			<required>false</required>
			<rtexprvalue>false</rtexprvalue>
		</attribute>
		<attribute>
			<name>value</name>
			<required>true</required>
			<rtexprvalue>false</rtexprvalue>
		</attribute>
		<attribute>
			<name>text</name>
			<required>true</required>
			<rtexprvalue>false</rtexprvalue>
		</attribute>
		<attribute>
			<name>selectValue</name>
			<required>false</required>
			<rtexprvalue>false</rtexprvalue>
		</attribute>
	</tag>
	
	<tag>
		<name>paging</name>
		<tag-class>com.pf.mymvc.tag.PagingTag</tag-class>
		<body-content>empty</body-content>
		<description>分页标签</description>
		<attribute>
			<name>pageBean</name>
			<required>true</required>
			<rtexprvalue>true</rtexprvalue>
		</attribute>
	</tag>
	
</taglib>

2.2.8编写界面

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>

<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%>
<%@ taglib prefix="z" uri="/pf"%>

<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<body>

	<h1>学生信息</h1>
	
	<form action="<%=request.getContextPath()%>/studentAction.action?methodName=getStudents" method="post">
		<input type="text" name="sname" value="<%=request.getParameter("sname") == null ? "" : request.getParameter("sname")%>"/>
		<input type="submit" value="查询">
	</form>
	
	<table border="1" style="width: 98%;">
	
		<tr>
			<td>学号</td>
			<td>姓名</td>
			<td>成绩</td>
			<td>班级</td>
		</tr>
		
		<c:forEach items="${students}" var="student">
			<tr>
				<td>${student.sid}</td>
				<td>${student.sname}</td>
				<td>${student.score}</td>
				<td>${student.clazz}</td>
			</tr>
		</c:forEach>
	</table>
	
	<z:paging pageBean="${pageBean}"/>

</body>
</html>

测试一下（http://localhost:8080/mymvcdemo/studentAction.action?methodName=getStudents）