public abstract class JdkVersion {
public static final int JAVA_13 = 0;
public static final int JAVA_14 = 1;
public static final int JAVA_15 = 2;
public static final int JAVA_16 = 3;
public static final int JAVA_17 = 4;
//for jre 1.8
public static final int JAVA_18 = 5;
private static final String javaVersion = System
.getProperty("java.version");
private static final int majorJavaVersion;
public static String getJavaVersion() {
return javaVersion;
}
public static int getMajorJavaVersion() {
return majorJavaVersion;
}
public static boolean isAtLeastJava14() {
return true;
}
public static boolean isAtLeastJava15() {
return getMajorJavaVersion() >= 2;
}
public static boolean isAtLeastJava16() {
return getMajorJavaVersion() >= 3;
}
static {
//for jre 1.8
if (javaVersion.indexOf("1.8.") != -1) {
majorJavaVersion = 5;
}else if (javaVersion.indexOf("1.7.") != -1) {
majorJavaVersion = 4;
} else if (javaVersion.indexOf("1.6.") != -1) {
majorJavaVersion = 3;
} else if (javaVersion.indexOf("1.5.") != -1) {
majorJavaVersion = 2;
} else {
majorJavaVersion = 1;
}
}
}
public static final int JAVA_13 = 0;
public static final int JAVA_14 = 1;
public static final int JAVA_15 = 2;
public static final int JAVA_16 = 3;
public static final int JAVA_17 = 4;
//for jre 1.8
public static final int JAVA_18 = 5;
private static final String javaVersion = System
.getProperty("java.version");
private static final int majorJavaVersion;
public static String getJavaVersion() {
return javaVersion;
}
public static int getMajorJavaVersion() {
return majorJavaVersion;
}
public static boolean isAtLeastJava14() {
return true;
}
public static boolean isAtLeastJava15() {
return getMajorJavaVersion() >= 2;
}
public static boolean isAtLeastJava16() {
return getMajorJavaVersion() >= 3;
}
static {
//for jre 1.8
if (javaVersion.indexOf("1.8.") != -1) {
majorJavaVersion = 5;
}else if (javaVersion.indexOf("1.7.") != -1) {
majorJavaVersion = 4;
} else if (javaVersion.indexOf("1.6.") != -1) {
majorJavaVersion = 3;
} else if (javaVersion.indexOf("1.5.") != -1) {
majorJavaVersion = 2;
} else {
majorJavaVersion = 1;
}
}
}
本文介绍了一个用于检测Java运行环境版本的抽象类JdkVersion的设计与实现细节。该类通过读取系统的java.version属性来判断当前环境的大致版本,并提供了一系列方法供外部调用以检查当前环境是否至少为某个特定的Java版本。
1万+

被折叠的 条评论
为什么被折叠?



