本文主要是介绍7.27--SSH学习之SpringMVC，Ajax请求、拦截器、文件上传和MyBatis访问数据库基本操作，希望对大家解决编程问题提供一定的参考价值，需要的开发者们随着小编来一起学习吧！
第一点：ajax请求
在一个表单中由jquery发起一个ajax请求，然后访问控制器，返回json结果，最后把结果显示在原表单中。
1. 下面是一个用户注册页面，当输入用户名时就立即发起ajax请求，来判断这个用户名是否可用
注册表单如下：
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%><!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html><head><base href="<%=basePath%>"><title>My JSP 'adduser.jsp' starting page</title><meta http-equiv="pragma" content="no-cache"><meta http-equiv="cache-control" content="no-cache"><meta http-equiv="expires" content="0"> <meta http-equiv="keywords" content="keyword1,keyword2,keyword3"><meta http-equiv="description" content="This is my page"><!--<link rel="stylesheet" type="text/css" href="styles.css">--><script type="text/javascript" src="js/jquery-1.9.1.min.js"></script><script type="text/javascript">$(function(){$("#loginId").bind("blur",function(){var loginId = $("#loginId").val();$.ajax({url:"checkuserexist.action",type:"post",data:{"userName":loginId,"userPwd":"11111","userlevel":"VIP"},datatype:"json",success:function(data){// alert("aaaa")$("#userInfo").html(data.resultStr);}});});});</script></head><body><form action="listuser.jsp" method="post">账号：<input type="text" name="loginId" id="loginId" value="小篆风"><span style="color:red" id="userInfo"></span><br>密码：<input type="password" name="loginPwd" id="loginPwd" value="1111"><br><input type="submit" value="注册"></form></body>
</html>
在上面的ajax请求中访问名为checkuserexist.action的控制器方法，代码如下：
@RequestMapping("checkuserexist.action")public @ResponseBody ResultData checkUserExist(User user)throws Exception{ResultData rd = new ResultData();System.out.println(user.getUserName());System.out.println(user.getUserPwd());System.out.println(user.getUserlevel());if(user.getUserName().equals("Tom")){rd.setResultStr("此用户已存在，请重新输入");}else{rd.setResultStr("用户名可以使用");}return rd;}
当然上面为了简单，就没有访问数据库，直接写了一个限制用户名，在项目开发中就需要访问数据库，然后把结果回显到原表单了。
另外一个就是显示数据库中某个表的数据，也是通过ajax请求完成，找到数据后还要重新绘制页面，以便数据显示呢。
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%><!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html><head><base href="<%=basePath%>"><title>My JSP 'listuser.jsp' starting page</title><meta http-equiv="pragma" content="no-cache"><meta http-equiv="cache-control" content="no-cache"><meta http-equiv="expires" content="0"> <meta http-equiv="keywords" content="keyword1,keyword2,keyword3"><meta http-equiv="description" content="This is my page"><!--<link rel="stylesheet" type="text/css" href="styles.css">--><script type="text/javascript" src="js/jquery-1.9.1.min.js"></script><script type="text/javascript">$(function(){$.ajax({url:"findalluser.action",type:"post",success:function(data){for(var i = 0;i< data.length;i++){var newRow = "<tr><td>"+data[i].userName+"</td><td>"+data[i].userPwd+"</td><td>"+data[i].userlevel+"</td><tr>";$("#userTable").append(newRow);//完成ajax请求需要对页面重新绘制}}});});</script></head><body><table border="1" id="userTable"><tr><td>用户名</td><td>密码</td><td>等级</td></tr></table></body>
</html>
第二点：拦截器
在SpringMVC中用户登录时先访问拦截器再执行验证登陆的方法
<body><form action="login.action" method="post">用户名：<input type="text" name="userName" value="susu"><br>密码：<input type="password" name="userPwd" value="1111"><br><input type="submit" value="Login"></form></body>
在上面表单提交的action需要在springmvc.xml中配置拦截器
<!-- 配置SpringMVC的拦截器 --><mvc:interceptors><mvc:interceptor><mvc:mapping path="/login.action"/><bean class="com.su.interceptor.FirstInterceptor"></bean></mvc:interceptor></mvc:interceptors>
拦截器中有三个方法，依次按照其功能执行
public class FirstInterceptor implements HandlerInterceptor {@Override //Handler方法执行完毕后执行的方法public void afterCompletion(HttpServletRequest request,HttpServletResponse response, Object obj, Exception ex)throws Exception {System.out.println("in FirstInterceptor method afterCompletion()");}@Override //进入Handler方法后，返回ModelAndView之前执行的方法public void postHandle(HttpServletRequest request, HttpServletResponse response,Object obj, ModelAndView model) throws Exception {System.out.println("in FirstInterceptor method postHandle()");}@Override //进入Handler方法前执行的方法public boolean preHandle(HttpServletRequest request, HttpServletResponse response,Object obj) throws Exception {System.out.println("in FirstInterceptor method preHandle()");return true;}}
执行拦截器中的方法后，再执行控制器中的方法
@RequestMapping("login.action")public ModelAndView userLogin() throws Exception{System.out.println("in UserController method userLogin()");ModelAndView mav = new ModelAndView();mav.setViewName("success.jsp");System.out.println("userLogin()方法执行完毕！！");return mav;}
控制台输出的信息一目了然：
信息: FrameworkServlet 'DispatcherServlet': initialization completed in 2096 ms
in FirstInterceptor method preHandle()
in UserController method userLogin()
userLogin()方法执行完毕！！
in FirstInterceptor method postHandle()
in FirstInterceptor method afterCompletion()第三点：文件上传
一般在项目开发中上传的都是图片，这里演示上传图片的内容
1. 在上传表单页面，输入用户名然后选择图片，选择的图片可以立即显示
这里是通过js代码实现的
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%><!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html><head><base href="<%=basePath%>"><title>My JSP 'upfie.jsp' starting page</title><meta http-equiv="pragma" content="no-cache"><meta http-equiv="cache-control" content="no-cache"><meta http-equiv="expires" content="0"> <meta http-equiv="keywords" content="keyword1,keyword2,keyword3"><meta http-equiv="description" content="This is my page"><!--<link rel="stylesheet" type="text/css" href="styles.css">--><script type="text/javascript">function showPicture(){var path=document.getElementById("upfile").value;var first = "C:\\Users\\su\\Pictures\\Saved Pictures\\";var second = path.substr(path.lastIndexOf("\\")+1);var third = first + second;alert(third)document.getElementById("showPic").src = third; }</script></head><body><form action="upload/upfile.action" method="post" enctype="multipart/form-data">用户名：<input type="text" name="userName"/><br><img src="" id="showPic" width="300" height="200"><br>上传文件:<input type="file" name="upfile" id="upfile" onChange="showPicture()"><br><input type="submit" value="Upload"> </form></body>
</html>
效果如下图：
文件上传的控制器代码如下：
@Controller
@RequestMapping("upload")
public class FileUploadController {@RequestMapping("upfile.action")public ModelAndView uploadFile(String userName,MultipartFile upfile,HttpServletRequest request)throws Exception{System.out.println("in FileUploadController method uploadFile()");System.out.println(userName);ModelAndView mav = new ModelAndView();//从上传对象中获取文件名String fileName = upfile.getOriginalFilename();//获取工程路径+上传文件夹+上传文件名String filepath = request.getServletContext().getRealPath("/file/"+fileName);System.out.println(filepath);//创建上传文件对象File file = new File(filepath);//执行文件上传upfile.transferTo(file);mav.setViewName("success.jsp");return mav;}
}
在配置文件中也要配置
<!-- 设置文件上传 --><bean id="multipartResolver" class="org.springframework.web.multipart.commons.CommonsMultipartResolver"><!-- 设置上传文件最大为3MB,单位为byte --><property name="maxUploadSize"><value>3145728</value></property></bean>
对上面前三点完整的配置文件如下：
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"xmlns:mvc="http://www.springframework.org/schema/mvc" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"xmlns:aop="http://www.springframework.org/schema/aop" xmlns:tx="http://www.springframework.org/schema/tx"xmlns:p="http://www.springframework.org/schema/p" xmlns:context="http://www.springframework.org/schema/context"xsi:schemaLocation="http://www.springframework.org/schema/beanshttp://www.springframework.org/schema/beans/spring-beans-4.3.xsdhttp://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.3.xsdhttp://www.springframework.org/schema/mvchttp://www.springframework.org/schema/mvc/spring-mvc-4.3.xsdhttp://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-4.3.xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-4.3.xsd"><!-- 指定自动扫描com.su.controller包下的控制器类 --><context:component-scan base-package="com.su.controller"></context:component-scan><!-- 自动加载注解适配器和映射器 --><mvc:annotation-driven></mvc:annotation-driven><!-- 视图解析器 --><bean class="org.springframework.web.servlet.view.InternalResourceViewResolver"><!-- 配置jsp路径的前缀<property name="prefix" value="/result/" />--><!-- 配置jsp路径的后缀<property name="suffix" value=".jsp" />--></bean> <!-- 配置SpringMVC的拦截器 --><mvc:interceptors><mvc:interceptor><mvc:mapping path="/login.action"/><bean class="com.su.interceptor.FirstInterceptor"></bean></mvc:interceptor></mvc:interceptors><!-- 设置文件上传 --><bean id="multipartResolver" class="org.springframework.web.multipart.commons.CommonsMultipartResolver"><!-- 设置上传文件最大为3MB,单位为byte --><property name="maxUploadSize"><value>3145728</value></property></bean>
</beans>第四点：Mybatis访问数据库
Mybatis不同于Hibernate可以自动建表，Mybatis需要手动在数据库中建好表，然后再访问。
下面介绍对Student表的数据库操作
Student.java
package com.su.domain;public class Student {private Integer stuId;private String stuName;private String stuGender;private Integer stuAge;private Integer classesId;public Integer getClassesId() {return classesId;}public void setClassesId(Integer classesId) {this.classesId = classesId;}public Integer getStuId() {return stuId;}public void setStuId(Integer stuId) {this.stuId = stuId;}public String getStuName() {return stuName;}public void setStuName(String stuName) {this.stuName = stuName;}public String getStuGender() {return stuGender;}public void setStuGender(String stuGender) {this.stuGender = stuGender;}public Integer getStuAge() {return stuAge;}public void setStuAge(Integer stuAge) {this.stuAge = stuAge;}
}
对应Student类的配置文件Student.xml如下：
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-mapper.dtd"><mapper namespace="student"><!-- 查询全部 --><select id="findAllStudents" resultType="student">select * from student</select><!-- 根据id查询 --><select id="findStudentById" parameterType="java.lang.Integer" resultType="student">select * from student where stuid = #{value}</select><!-- 根据姓名模糊查询 --><select id="findStudentByName" parameterType="java.lang.String" resultType="student">select * from student where stuname like '%${value}%'</select><!-- 根据姓名和性别查询 --><select id="findStudentByBean" parameterType="student" resultType="student">select * from student where stuname like '%${stuName}%' and stugender = #{stuGender}</select><!-- 根据条件查找全部数量 --><select id="findStudentToCount" parameterType="student" resultType="java.lang.Integer">select count(*) from student where stuname like '%${stuName}%' and stugender = #{stuGender}</select><!-- 新增学生信息 --><insert id="addStudent" parameterType="student"><selectKey keyProperty="stuId" order="BEFORE" resultType="java.lang.Integer">SELECT stu_seq.nextval from dual</selectKey>insert into student values(#{stuId},#{stuName},#{stuGender},#{stuAge},#{classesId})</insert><!-- 更新学生信息 --><update id="updateStudent" parameterType="student">update student set stuname=#{stuName},stugender=#{stuGender},stuage=#{stuAge},classesid=#{classesId} where stuid=#{stuId}</update><!-- 根据id删除信息 --><delete id="deleteStudent" parameterType="java.lang.Integer">delete from student where stuid=#{stuId}</delete></mapper>
测试类：
package com.su.test;import java.io.InputStream;
import java.util.List;import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;import com.su.domain.Student;public class MainTest {public static void main(String[] args) {try{//加载配置文件InputStream is = Resources.getResourceAsStream("mybatisconfig.xml");//创建SqlSessionFactory对象SqlSessionFactory ssf = new SqlSessionFactoryBuilder().build(is);//创建SqlSessionSqlSession ss = ssf.openSession();//查询全部数据
// List<Student> list = ss.selectList("student.findAllStudents");
// for(Student stu : list){
// System.out.println(stu.getStuId()+"\t"+stu.getStuName());
// }//根据id查询Student stu = ss.selectOne("findStudentById", 2);System.out.println(stu.getStuName());//根据姓名模糊查询
// List<Student> list = ss.selectList("findStudentByName", 'r');
// for(Student stu : list)
// System.out.println(stu.getStuName());//根据姓名和性别查询
// Student stu = new Student();
// stu.setStuName("o");
// stu.setStuGender("男");
// List<Student> list = ss.selectList("findStudentByBean", stu);
// for(Student stu1 : list)
// System.out.println(stu1.getStuName());//根据条件查找全部数量
// Student stu = new Student();
// stu.setStuName("o");
// stu.setStuGender("男");
// Integer count = ss.selectOne("findStudentToCount", stu);
// System.out.println("共有："+count+"条记录");//新增学员
// Student stu = new Student();
// stu.setStuName("小强");
// stu.setStuGender("女");
// stu.setStuAge(18);
// stu.setClassesId(1);
// int result = ss.insert("addStudent",stu);
// if(result==1){
// System.out.println("新增成功");
// System.out.println(stu.getStuId());
// }else{
// System.out.println("新增失败");
// }//更新学生信息
// Student stu = new Student();
// stu.setStuId(4);
// stu.setStuName("susu");
// stu.setStuGender("男");
// stu.setStuAge(22);
// stu.setClassesId(2);
// int result = ss.update("updateStudent",stu);
// if(result==1){
// System.out.println("更新成功");
// System.out.println(stu.getStuId());
// }else{
// System.out.println("更新失败");
// }//根据id删除信息
// Integer result = ss.delete("deleteStudent", 3);
// if(result==1){
// System.out.println("删除成功");
//
// }else{
// System.out.println("删除失败");
// }ss.commit();ss.close(); }catch(Exception e){e.printStackTrace();}}
}
在mybatisconfig.xml配置文件中需要进行一些配置：
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE configuration PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-config.dtd"><configuration><!-- 加载配置文件 --><properties resource="jdbc.properties"></properties><!-- 配置全局参数 --><settings><!-- 打开延迟加载的开关 --><setting name="lazyLoadingEnabled" value="true"/><!-- 将积极加载改为消极加载即按需要加载 --><setting name="aggressiveLazyLoading" value="false"/><!-- 开启二级缓存 --><setting name="cacheEnabled" value="true"/></settings> <typeAliases><!-- 单个类定义别名 type:类型的路径 alias:别名--><!-- <typeAlias type="com.mbd.domain.Student" alias="student"/> --><!-- 指定包名，mybatis自动扫描包中所有实体类，自动定义别名，别名就是类名（首字母大写或小写都可以）--><package name="com.su.domain"/> </typeAliases><!-- 声明数据连接环境 --><environments default="development"><environment id="development"><!-- 使用jdbc事务管理 --><transactionManager type="JDBC" /><!-- 数据库连接池 <dataSource type="POOLED"><property name="driver" value="oracle.jdbc.driver.OracleDriver" /><property name="url" value="jdbc:oracle:thin:@localhost:1521:xe" /><property name="username" value="school" /><property name="password" value="1573" /></dataSource>--><dataSource type="POOLED"><property name="driver" value="${driverClass}" /><property name="url" value="${jdbcUrl}" /><property name="username" value="${user}" /><property name="password" value="${password}" /></dataSource> </environment></environments><!-- 加载映射文件 --><mappers><mapper resource="com/su/domain/Student.xml"/></mappers>
</configuration>
为了代码的可移植性，有数据库链接配置文件jdbc.properties
driverClass=oracle.jdbc.driver.OracleDriver
jdbcUrl=jdbc:oracle:thin:@localhost:1521:xe
user=school
password=1573
`以上就是今天复习内容，以便日后查看
Author:1573
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