Spring MVC CRUD應用程序

Question

我剛剛開始學習spring mvc，但是我有一個問題。 我試圖運行在javatpoint網站上找到的名為Spring MVC CRUD Example的應用程序，但出現了一個錯誤。 一切正常，除了更新表。 當我單擊編輯鏈接時，我得到HTTP狀態[500]。 下面是我所有文件的代碼。 拜托，有人幫我解決這個問題。

pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.damian</groupId>
<artifactId>myapp</artifactId>
<name>CRUD</name>
<packaging>war</packaging>
<version>1.0.0-BUILD-SNAPSHOT</version>
<properties>
    <java-version>1.6</java-version>
    <org.springframework-version>3.1.1.RELEASE</org.springframework-version>
    <org.aspectj-version>1.6.10</org.aspectj-version>
    <org.slf4j-version>1.6.6</org.slf4j-version>
</properties>
<dependencies>
    <!-- Spring -->
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-context</artifactId>
        <version>${org.springframework-version}</version>
        <exclusions>
            <!-- Exclude Commons Logging in favor of SLF4j -->
            <exclusion>
                <groupId>commons-logging</groupId>
                <artifactId>commons-logging</artifactId>
            </exclusion>
        </exclusions>
    </dependency>
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-webmvc</artifactId>
        <version>${org.springframework-version}</version>
    </dependency>

    <!-- AspectJ -->
    <dependency>
        <groupId>org.aspectj</groupId>
        <artifactId>aspectjrt</artifactId>
        <version>${org.aspectj-version}</version>
    </dependency>

    <!-- Logging -->
    <dependency>
        <groupId>org.slf4j</groupId>
        <artifactId>slf4j-api</artifactId>
        <version>${org.slf4j-version}</version>
    </dependency>
    <dependency>
        <groupId>org.slf4j</groupId>
        <artifactId>jcl-over-slf4j</artifactId>
        <version>${org.slf4j-version}</version>
        <scope>runtime</scope>
    </dependency>
    <dependency>
        <groupId>org.slf4j</groupId>
        <artifactId>slf4j-log4j12</artifactId>
        <version>${org.slf4j-version}</version>
        <scope>runtime</scope>
    </dependency>
    <dependency>
        <groupId>log4j</groupId>
        <artifactId>log4j</artifactId>
        <version>1.2.15</version>
        <exclusions>
            <exclusion>
                <groupId>javax.mail</groupId>
                <artifactId>mail</artifactId>
            </exclusion>
            <exclusion>
                <groupId>javax.jms</groupId>
                <artifactId>jms</artifactId>
            </exclusion>
            <exclusion>
                <groupId>com.sun.jdmk</groupId>
                <artifactId>jmxtools</artifactId>
            </exclusion>
            <exclusion>
                <groupId>com.sun.jmx</groupId>
                <artifactId>jmxri</artifactId>
            </exclusion>
        </exclusions>
        <scope>runtime</scope>
    </dependency>

    <!-- @Inject -->
    <dependency>
        <groupId>javax.inject</groupId>
        <artifactId>javax.inject</artifactId>
        <version>1</version>
    </dependency>

    <!-- Servlet -->
    <dependency>
        <groupId>javax.servlet</groupId>
        <artifactId>servlet-api</artifactId>
        <version>2.5</version>
        <scope>provided</scope>
    </dependency>
    <dependency>
        <groupId>javax.servlet.jsp</groupId>
        <artifactId>jsp-api</artifactId>
        <version>2.1</version>
        <scope>provided</scope>
    </dependency>
    <dependency>
        <groupId>javax.servlet</groupId>
        <artifactId>jstl</artifactId>
        <version>1.2</version>
    </dependency>

    <!-- Test -->
    <dependency>
        <groupId>junit</groupId>
        <artifactId>junit</artifactId>
        <version>4.7</version>
        <scope>test</scope>
    </dependency>

    <!-- https://mvnrepository.com/artifact/org.springframework/spring-jdbc -->
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-jdbc</artifactId>
        <version>4.3.9.RELEASE</version>
    </dependency>

    <!-- https://mvnrepository.com/artifact/mysql/mysql-connector-java -->
    <dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql-connector-java</artifactId>
        <version>5.1.6</version>
    </dependency>



</dependencies>
<build>
    <plugins>
        <plugin>
            <artifactId>maven-eclipse-plugin</artifactId>
            <version>2.9</version>
            <configuration>
                <additionalProjectnatures>
                    <projectnature>org.springframework.ide.eclipse.core.springnature</projectnature>
                </additionalProjectnatures>
                <additionalBuildcommands>
                    <buildcommand>org.springframework.ide.eclipse.core.springbuilder</buildcommand>
                </additionalBuildcommands>
                <downloadSources>true</downloadSources>
                <downloadJavadocs>true</downloadJavadocs>
            </configuration>
        </plugin>
        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-compiler-plugin</artifactId>
            <version>2.5.1</version>
            <configuration>
                <source>1.6</source>
                <target>1.6</target>
                <compilerArgument>-Xlint:all</compilerArgument>
                <showWarnings>true</showWarnings>
                <showDeprecation>true</showDeprecation>
            </configuration>
        </plugin>
        <plugin>
            <groupId>org.codehaus.mojo</groupId>
            <artifactId>exec-maven-plugin</artifactId>
            <version>1.2.1</version>
            <configuration>
                <mainClass>org.test.int1.Main</mainClass>
            </configuration>
        </plugin>
    </plugins>
</build>

web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.5" xmlns="http://java.sun.com/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">
    <!-- The definition of the Root Spring Container shared by all Servlets 
    and Filters -->
<context-param>
    <param-name>contextConfigLocation</param-name>
    <param-value>/WEB-INF/spring/root-context.xml</param-value>
</context-param>

<!-- Creates the Spring Container shared by all Servlets and Filters -->
<listener>
    <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
</listener>

<!-- Processes application requests -->
<servlet>
    <servlet-name>appServlet</servlet-name>
    <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
    <init-param>
        <param-name>contextConfigLocation</param-name>
        <param-value>/WEB-INF/spring/appServlet/servlet-context.xml</param-value>
    </init-param>
    <load-on-startup>1</load-on-startup>
</servlet>

<servlet-mapping>
    <servlet-name>appServlet</servlet-name>
    <url-pattern>/</url-pattern>
</servlet-mapping>

servlet-context.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans:beans xmlns="http://www.springframework.org/schema/mvc"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:beans="http://www.springframework.org/schema/beans"
xmlns:context="http://www.springframework.org/schema/context"
xsi:schemaLocation="http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc.xsd
    http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
    http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd">

<!-- DispatcherServlet Context: defines this servlet's request-processing infrastructure -->

<!-- Enables the Spring MVC @Controller programming model -->
<annotation-driven />

<!-- Handles HTTP GET requests for /resources/** by efficiently serving up static resources in the ${webappRoot}/resources directory -->
<resources mapping="/resources/**" location="/resources/" />

<!-- Resolves views selected for rendering by @Controllers to .jsp resources in the /WEB-INF/views directory -->
<beans:bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
    <beans:property name="prefix" value="/WEB-INF/views/" />
    <beans:property name="suffix" value=".jsp" />
</beans:bean>

<context:component-scan base-package="com.damian.myapp" />

root-context.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:context="http://www.springframework.org/schema/context"
xmlns:jdbc="http://www.springframework.org/schema/jdbc"
xmlns:mvc="http://www.springframework.org/schema/mvc"
xsi:schemaLocation="http://www.springframework.org/schema/jdbc http://www.springframework.org/schema/jdbc/spring-jdbc-4.3.xsd
    http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-3.1.xsd
    http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
    http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.1.xsd">

<!-- Root Context: defines shared resources visible to all other web components -->
<context:annotation-config />

<bean id="ds"
    class="org.springframework.jdbc.datasource.DriverManagerDataSource">
    <property name="driverClassName" value="com.mysql.jdbc.Driver" />
    <property name="url" value="jdbc:mysql://localhost:3306/samp_db" />
    <property name="username" value="root" />
    <property name="password" value="mysql" />
</bean>

<bean id="jt" class="org.springframework.jdbc.core.JdbcTemplate">
    <property name="dataSource" ref="ds" />
</bean>

<bean id="dao" class="com.damian.myapp.dao.EmpDao">
    <property name="template" ref="jt" />
</bean>

index.jsp

<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
pageEncoding="ISO-8859-1"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
      <meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
      <title>Insert title here</title>
</head>
<body>
     <a href="empform.html">Add new employee</a>
     <a href="viewemp.html">Show all employees</a>
</body>
</html>

empeditform.jsp

<%@ taglib uri="http://www.springframework.org/tags/form" prefix="form"%>
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%>
<h1>Edit Employee</h1>
<form:form method="POST" action="/CRUD/editsave">
<table>
    <tr>
        <td></td>
        <td><form:hidden path="id" /></td>
    </tr>
    <tr>
        <td>Name :</td>
        <td><form:input path="name" /></td>
    </tr>
    <tr>
        <td>Salary :</td>
        <td><form:input path="salary" /></td>
    </tr>
    <tr>
        <td>Designation :</td>
        <td><form:input path="designation" /></td>
    </tr>

    <tr>
        <td></td>
        <td><input type="submit" value="Edit Save" /></td>
    </tr>
</table>

empform.jsp

<%@ taglib uri="http://www.springframework.org/tags/form" prefix="form"%>
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%>
<h1>Add New Employee</h1>
<form:form method="post" action="save">
<table>
    <tr>
        <td>Name :</td>
        <td><form:input path="name" /></td>
    </tr>
    <tr>
        <td>Salary :</td>
        <td><form:input path="salary" /></td>
    </tr>
    <tr>
        <td>Designation :</td>
        <td><form:input path="designation" /></td>
    </tr>
    <tr>
        <td></td>
        <td><input type="submit" value="Save" /></td>
    </tr>
</table>

viewemp.jsp

<%@ taglib uri="http://www.springframework.org/tags/form" prefix="form"%>
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%>
<table border="2" width="70%" cellpadding="2">
<tr><th>Id</th><th>Name</th><th>Salary</th><th>Designation</th></tr>
<c:forEach var="emp" items="${list }">
    <tr>
        <td>${emp.id }</td>
        <td>${emp.name }</td>
        <td>${emp.salary }</td>
        <td>${emp.designation }</td>
        <td><a href="editemp/${emp.id}">Edit</a></td>
        <td><a href="deleteemp/${emp.id}">Delete</a></td>
    </tr>
</c:forEach>
</table>
<a href="empform.html">Add New Employee</a>  

EmpController.java

package com.damian.myapp;

import java.util.List;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.ModelAttribute;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.servlet.ModelAndView;

import com.damian.myapp.beans.Emp;
import com.damian.myapp.dao.EmpDao;

@Controller
public class EmpController {

    @Autowired
    EmpDao dao;

    @RequestMapping("/empform")
    public ModelAndView showform() {
        return new ModelAndView("empform", "command", new Emp());
    }

    @RequestMapping(value = "/save", method = RequestMethod.POST)
    public ModelAndView save(@ModelAttribute("emp") Emp emp) {
        dao.save(emp);
        return new ModelAndView("redirect:/viewemp");
    }

    @RequestMapping("/viewemp")
    public ModelAndView viewemp() {
        List<Emp> list = dao.getEmployees();
        return new ModelAndView("viewemp", "list", list);
    }

    @RequestMapping(value = "/editemp/{id}")
    public ModelAndView edit(@PathVariable int id) {
        Emp emp = dao.getEmpById(id);
        return new ModelAndView("empeditform", "command", emp);
    }

    @RequestMapping(value = "/editsave", method = RequestMethod.POST)
    public ModelAndView editsave(@ModelAttribute("emp") Emp emp) {
        dao.update(emp);
        return new ModelAndView("redirect:/viewemp");
    }

    @RequestMapping(value = "/deleteemp/{id}", method = RequestMethod.GET)
    public ModelAndView delete(@PathVariable int id) {
        dao.delete(id);
        return new ModelAndView("redirect:/viewemp");
    }
}

Emp.java

package com.damian.myapp.beans;

public class Emp {
    private int id;
    private String name;
    private float salary;
    private String designation;

    public Emp(){

    }

    public Emp(int id, String name, float salary, String designation) {
        this.id = id;
        this.name = name;
        this.salary = salary;
        this.designation = designation;
    }

    @Override
    public String toString() {
        return "Emp [id=" + id + ", name=" + name + ", salary=" + salary + ", designation=" + designation + "]";
    }

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public float getSalary() {
        return salary;
    }

    public void setSalary(float salary) {
        this.salary = salary;
    }

    public String getDesignation() {
        return designation;
    }

    public void setDesignation(String designation) {
        this.designation = designation;
    }

}

EmpDao.java

package com.damian.myapp.dao;

import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;

import org.springframework.dao.DataAccessException;
import org.springframework.jdbc.core.BeanPropertyRowMapper;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.jdbc.core.ResultSetExtractor;

import com.damian.myapp.beans.Emp;

public class EmpDao {

    private JdbcTemplate template;

    public void setTemplate(JdbcTemplate template) {
        this.template = template;
    }

    public int save(Emp p) {
        String sql = "INSERT INTO emp99(name, salary, designation) VALUES('" + p.getName() + "', " + p.getSalary()
                + ", '" + p.getDesignation() + "')";

        return template.update(sql);
    }

    public int update(Emp p) {

        String sql = "update Emp99 set name='"+p.getName()+"', salary="+p.getSalary()+
                ", designation='"+p.getDesignation()+"' where id="+p.getId()+"";

        return template.update(sql);

    }

    public int delete(int id) {

        String sql = "DELETE FROM emp99 WHERE id=" + id + "";

        return template.update(sql);

    }

    public Emp getEmpById(int id) {

        String sql = "SELECT * FROM emp99 WHERE id=?";

        return template.queryForObject(sql, new Object[] { id }, new BeanPropertyRowMapper<Emp>(Emp.class));

    }

    public List<Emp> getEmployees() {

        return template.query("SELECT * FROM emp99", new ResultSetExtractor<List<Emp>>(){

            @Override
            public List<Emp> extractData(ResultSet rs) throws SQLException, DataAccessException {

                List<Emp> list=new ArrayList<Emp>();

                while(rs.next()){
                    Emp e = new Emp();
                    e.setId(rs.getInt(1));
                    e.setName(rs.getString(2));
                    e.setSalary(rs.getFloat(3));
                    e.setDesignation(rs.getString(4));
                    list.add(e);
                }

                return list;
            }

        });
    }

}

當我單擊“編輯”鏈接時，出現以下異常：

lip 13, 2017 6:26:32 PM org.apache.catalina.core.StandardWrapperValve invoke
SEVERE: Servlet.service() for servlet [appServlet] in context with path [/myapp] threw exception [Handler processing failed; nested exception is java.lang.NoSuchMethodError: org.springframework.core.convert.support.DefaultConversionService.getSharedInstance()Lorg/springframework/core/convert/ConversionService;] with root cause
java.lang.NoSuchMethodError: org.springframework.core.convert.support.DefaultConversionService.getSharedInstance()Lorg/springframework/core/convert/ConversionService;
    at org.springframework.jdbc.core.BeanPropertyRowMapper.<init>(BeanPropertyRowMapper.java:91)
    at com.damian.myapp.dao.EmpDao.getEmpById(EmpDao.java:51)
    at com.damian.myapp.EmpController.edit(EmpController.java:41)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
    at java.lang.reflect.Method.invoke(Unknown Source)
    at org.springframework.web.method.support.InvocableHandlerMethod.invoke(InvocableHandlerMethod.java:213)
    at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:126)
    at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:96)
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:617)
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:578)
    at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:80)
    at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:923)
    at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:852)
    at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:882)
    at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:778)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:635)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:742)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
    at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:199)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96)
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:475)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:140)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:80)
    at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:624)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:87)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:342)
    at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:498)
    at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66)
    at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:796)
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1368)
    at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
    at java.lang.Thread.run(Unknown Source)

Answer 1

問題的根本原因是您混合使用不同版本的spring依賴項：spring-jdbc的3.1.1.RELEASE和4.3.9.RELEASE版本。

從文檔中 ，我看到從版本4.3.5開始存在方法getSharedInstance。

Answer 2

使用新版本升級Spring框架： <version>4.3.9.RELEASE</version>或更高<version>4.3.9.RELEASE</version>