Context namespace element 'component-scan' and its parser class [org.springframework.context.annotation.ComponentScanBeanDefinitionParser] are only available on JDK 1.5 and higher

异常信息如下：

错误: Unexpected exception parsing XML document from class path resource [spring/applicationContext-db.xml]; nested exception is java.lang.IllegalStateException: Context namespace element 'component-scan' and its parser class [org.springframework.context.annotation.ComponentScanBeanDefinitionParser] are only available on JDK 1.5 and higher 

原因：

　　当前jdk版本的spring不支持注解，有两种方式解决这个问题。一是 换jdk，二是  加一个配置文件。

　　这里使用的是加一个配置文件：在src文件夹加org.springframework.core包，并添加一个JdkVersion.java文件，使注解能够识别jdk8。 

JdkVersion.java文件内容如下：

package org.springframework.core;

/**
 * Internal helper class used to find the Java/JVM version
 * that Spring is operating on, to allow for automatically
 * adapting to the present platform's capabilities.
 *
 * <p>Note that Spring requires JVM 1.5 or higher, as of Spring 3.0.
 *
 * @author Rod Johnson
 * @author Juergen Hoeller
 * @author Rick Evans
 */
public abstract class JdkVersion {

    /**
     * Constant identifying the 1.3.x JVM (JDK 1.3).
     */
    public static final int JAVA_13 = 0;

    /**
     * Constant identifying the 1.4.x JVM (J2SE 1.4).
     */
    public static final int JAVA_14 = 1;

    /**
     * Constant identifying the 1.5 JVM (Java 5).
     */
    public static final int JAVA_15 = 2;

    /**
     * Constant identifying the 1.6 JVM (Java 6).
     */
    public static final int JAVA_16 = 3;

    /**
     * Constant identifying the 1.7 JVM (Java 7).
     */
    public static final int JAVA_17 = 4;
    
    /**
     * Constant identifying the 1.8 JVM (Java 8).
     */
    public static final int JAVA_18 = 5;
    
    


    private static final String javaVersion;

    private static final int majorJavaVersion;

    static {
        javaVersion = System.getProperty("java.version");
        // version String should look like "1.4.2_10"
        if (javaVersion.contains("1.8.")) {
            majorJavaVersion = JAVA_18;
        }else if (javaVersion.contains("1.7.")) {
            majorJavaVersion = JAVA_17;
        }
        else if (javaVersion.contains("1.6.")) {
            majorJavaVersion = JAVA_16;
        }
        else {
            // else leave 1.5 as default (it's either 1.5 or unknown)
            majorJavaVersion = JAVA_15;
        }
    }


    /**
     * Return the full Java version string, as returned by
     * <code>System.getProperty("java.version")</code>.
     * @return the full Java version string
     * @see System#getProperty(String)
     */
    public static String getJavaVersion() {
        return javaVersion;
    }

    /**
     * Get the major version code. This means we can do things like
     * <code>if (getMajorJavaVersion() < JAVA_14)</code>.
     * @return a code comparable to the JAVA_XX codes in this class
     * @see #JAVA_13
     * @see #JAVA_14
     * @see #JAVA_15
     * @see #JAVA_16
     * @see #JAVA_17
     */
    public static int getMajorJavaVersion() {
        return majorJavaVersion;
    }


    /**
     * Convenience method to determine if the current JVM is at least Java 1.4.
     * @return <code>true</code> if the current JVM is at least Java 1.4
     * @deprecated as of Spring 3.0 which requires Java 1.5+
     * @see #getMajorJavaVersion()
     * @see #JAVA_14
     * @see #JAVA_15
     * @see #JAVA_16
     * @see #JAVA_17
     */
    @Deprecated
    public static boolean isAtLeastJava14() {
        return true;
    }

    /**
     * Convenience method to determine if the current JVM is at least
     * Java 1.5 (Java 5).
     * @return <code>true</code> if the current JVM is at least Java 1.5
     * @deprecated as of Spring 3.0 which requires Java 1.5+
     * @see #getMajorJavaVersion()
     * @see #JAVA_15
     * @see #JAVA_16
     * @see #JAVA_17
     */
    @Deprecated
    public static boolean isAtLeastJava15() {
        return true;
    }

    /**
     * Convenience method to determine if the current JVM is at least
     * Java 1.6 (Java 6).
     * @return <code>true</code> if the current JVM is at least Java 1.6
     * @deprecated as of Spring 3.0, in favor of reflective checks for
     * the specific Java 1.6 classes of interest
     * @see #getMajorJavaVersion()
     * @see #JAVA_16
     * @see #JAVA_17
     */
    @Deprecated
    public static boolean isAtLeastJava16() {
        return (majorJavaVersion >= JAVA_16);
    }

}