笔者平时时间有限，直接贴代码，关于几个接口的差别，可以查看这两篇文章
感受lambda之美，推荐收藏，需要时查阅
Java8 函数式编程读书总结
<T> List<T> readList(Table table, OID[] oids, String[] fieldNames, Class clazz, List<T> defaultValue, Predicate<? super T> filter, Consumer<? super List<T>> consumer, UnaryOperator<? super
@Override
public <T> List<T> readList(Table table, OID[] oids, String[] fieldNames, Class clazz, List<T> defaultValue, Predicate<? super T> filter, Consumer<? super List<T>> consumer, UnaryOperator<? super T> operator) {
if (table == null || table.isEmpty()) {
return defaultValue;
}
Class[] declaredFieldType = getDeclaredFieldType(fieldNames, clazz);
if(ArrayUtils.isEmpty(fieldNames)||ArrayUtils.isEmpty(declaredFieldType))
{
log.error("字段名长度和字段数据类型长度不能为null");
throw new IllegalArgumentException("字段名长度和字段数据类型长度不能为null");
}
if(!ArrayUtils.isSameLength(fieldNames, declaredFieldType))
{
throw new IllegalArgumentException("字段名个数与字段数据类型数组长度不一致");
}
Map<OID, Table.Row> rowMapping = table.getMap();
if(MapUtils.isEmpty(rowMapping)) {
return defaultValue;
}
log.debug("待查询oid名称:{}",String.join(",", fieldNames));
String [] oidInDottedString = Arrays.asList(oids).stream().map(OID::toDottedString).toArray(size->new String[size]);
List<T> list = new LinkedList<T>();
for(Table.Row row : rowMapping.values()) {
Set<OID> keys = row.getMap().keySet();
try {
T instance = (T)clazz.newInstance();
for (OID key : keys) {
String dotString = key.toDottedString();
for (int i = 0; i < oidInDottedString.length; i++) {
String oidString = oidInDottedString[i];
if (dotString.contains(oidString)) {
String fieldName = fieldNames[i];
Variable value = row.getVariable(key);
Class declaredType = declaredFieldType[i];
setProperty(instance,declaredType,fieldName,value);
}
}
}
list.add(instance);
}catch (IllegalAccessException|InstantiationException e)
{
log.error("提取属性失败:{}",e);
}
}
if(operator != null && CollectionUtils.isNotEmpty(list)) {
list.stream().forEach(instance->{operator.apply(instance);});
}
if(filter != null && CollectionUtils.isNotEmpty(list)) {
list = list.stream().filter(filter).collect(Collectors.toList());
}
if(consumer != null && CollectionUtils.isNotEmpty(list)) {
consumer.accept(list);
}
return list;
}
<T> T readObject(Table table, String[] fieldNames, Class clazz, T defaultValue,final Predicate<? super T> filter,final Consumer<? super T> consumer,final UnaryOperator<? super T> operator);
@Override
public <T> T readObject(Table table, String[] fieldNames, Class clazz, T defaultValue, Predicate<? super T> filter, Consumer<? super T> consumer, UnaryOperator<? super T> operator) {
if (table == null || table.isEmpty()) {
return defaultValue;
}
Optional<T> result = readList(table, fieldNames, clazz, Arrays.asList(defaultValue)/*, null, null, null*/).stream().findFirst();
return
用法:(方法签名会有出入,没有的签名方法，通过重载实现了，在此不贴出来代码，看官可自行实现，有疑问可跟帖留意交流)
//读取ip地址、子网掩码
Table ipAddrTable = snmpHelper.getTable(MIB.IpAddrTable);
List<SnmpIfCard> ifCards = agentService.readList(ipAddrTable,
agentService.translateOID(SnmpObjectNotation.ipAddrEntry),
SnmpObjectNotation.ipFieldNames, SnmpIfCard.class,
null,
(SnmpIfCard ifCard) -> {
if(ifCard!=null) {
//过滤掉回环地址
String ifIpAddr = ifCard.getIfIpAddr();
return !"127.0.0.1".equals(ifIpAddr);
}
return false;
},(SnmpIfCard ifCard)->{
if(ifCard != null) {
//设置nodeId
ifCard.setNodeId(nodeId);
return ifCard;
}
return null;
});
//网口流量
Table ifTable = snmpHelper.getTable(MIB.IfTable);
agentService.readList(ifTable,SnmpObjectNotation.trafficFieldNames,SnmpIfCardTraffic.class,
null,
(SnmpIfCardTraffic traffic)->{
if(traffic != null) {
Integer ifIndex = traffic.getIfIndex();
//如果网口索引里没有这个IfIndex,则不采集(通常是过滤IfIndex =1的本地回环网卡 lo)
List<Integer> allIfIndex = ifCards.stream().map(SnmpIfCard::getIfIndex).collect(Collectors.toList());
return allIfIndex.contains(ifIndex);
}
return false;
},
captured::setTraffics,
(SnmpIfCardTraffic traffic)->{
if(traffic != null) {
//通过网口索引匹配,将对应网口索引的子网掩码和ip地址拷贝到网口流量信息实体上面
Optional<SnmpIfCard> matched = matchIfCard(ifCards, traffic);
if (matched.isPresent()) {
traffic.setNodeId(nodeId);
traffic.setIfIpNetMask(matched.get().getIfIpNetMask());
traffic.setIfIpAddr(matched.get().getIfIpAddr());
}
return traffic;
}
return null;
});
//文件系统使用情况
Table hrStorageEntry = snmpHelper.getTable(MIB.hrStorageEntry);
agentService.readList(hrStorageEntry, SnmpObjectNotation.hrStorageEntryFields,
SnmpFileSystemUsage.class,null,
captured::setFsUsage,
(SnmpFileSystemUsage usage)->{
if(usage != null) {
usage.setNodeId(nodeId);
return usage;
}
return null;
});
//内存使用率
Table memory = snmpHelper.getTable(MIB.memory);
agentService.readObject(memory, SnmpObjectNotation.memoryFieldNames, SnmpMemoryUsage.class,
(SnmpMemoryUsage) null,
captured::setMemoryUsage,
(usage) -> {
if(usage !=null) {
usage.setNodeId(nodeId);
return usage;
}
return null;
});
//系统运行状态,从这里获取cpu使用率信息
Table sysStats = snmpHelper.getTable(MIB.systemStats);
agentService.readObject(sysStats, SnmpObjectNotation.systemStatFields, SnmpCPUUsage.class,
(SnmpCPUUsage)null,
captured::setCpuUsage,
(usage) -> {
if(usage !=null) {
usage.setNodeId(nodeId);
return usage;
}
return null;
});
Function的应用
defaultValue,
Predicate<? super T> filter, Consumer<? super List<T>> consumer, Function<? super T, ? extends R> mapper);
@Override
public <R,T> List<R> readTable(Table table, String[] fieldNames, Class clazz, Class[] declaredFieldType, List<T> defaultValue,
Predicate<? super T> filter, Consumer<? super List<T>> consumer, Function<? super T, ? extends R> mapper)
{
List<T> list = readList(table, fieldNames, clazz, declaredFieldType, defaultValue, filter, consumer);
return list.stream().map(item -> {
R target = mapper.apply(item);
return target;
}).collect(Collectors.toList());
}
@Override
public <T> List<T> readList(Table table, String[] fieldNames, Class clazz, Class[] declaredFieldType, List<T> defaultValue, Predicate<? super T> filter, Consumer<? super List<T>> consumer) {
return readList(table,fieldNames,clazz,declaredFieldType,defaultValue,filter,consumer,null);
}
