二級(jí)JAVA技巧:java判斷對(duì)象是否為空

/**
    * 空值檢查
    *
    * @param pInput 要檢查的字符串
    * @return boolean 返回檢查結(jié)果,但傳入的字符串為空的場(chǎng)合,返回真
    */
    public static boolean isNull (Object pInput) {
    // 判斷參數(shù)是否為空或者’’
    if (pInput == null || "’’".equals(pInput)) {
    return true;
    } else if ("java.lang.String".equals(pInput.getClass().getName())){
    // 判斷傳入的參數(shù)的String類型的
    // 替換各種空格
    String tmpInput = Pattern.compile("[\\r|\\n|\\u3000]")
    .matcher((String)pInput).replaceAll("");
    // 匹配空
    return Pattern.compile("^(\\s)*$")
    .matcher(tmpInput).matches();
    } else {
    // 方法類
    Method method = null;
    try {
    // 訪問(wèn)傳入?yún)?shù)的size方法
    method = pInput.getClass().getMethod("size");
    // 判斷size大小
    // size為0的場(chǎng)合
    if (Integer.parseInt(String.valueOf(method.invoke(pInput))) == 0) {
    return true;
    } else {
    return false;
    }
    } catch (Exception e) {
    // 訪問(wèn)失敗
    try {
    // 訪問(wèn)傳入?yún)?shù)的getItemCount方法
    method = pInput.getClass().getMethod("getItemCount");
    // 判斷size大小
    // getItemCount為0的場(chǎng)合
    if (Integer.parseInt(String.valueOf(method.invoke(pInput))) == 0) {
    return true;
    } else {
    return false;
    }
    } catch (Exception ex) {
    // 訪問(wèn)失敗
    try{
    // 判斷傳入?yún)?shù)的長(zhǎng)度
    // 長(zhǎng)度為0的場(chǎng)合
    if (Array.getLength(pInput) == 0) {
    return true;
    } else {
    return false;
    }
    } catch (Exception exx) {
    // 訪問(wèn)失敗
    try{
    // 訪問(wèn)傳入?yún)?shù)的hasNext方法
    method = Iterator.class.getMethod("hasNext");
    // 轉(zhuǎn)換hasNext的值
    return !Boolean.valueOf(String.valueOf(method.invoke(pInput)))? true : false;
    } catch (Exception exxx) {
    // 以上場(chǎng)合不滿足返回假
    return false;
    }
    }
    }
    }
    }
    }
    以下是測(cè)試代碼
    import java.awt.List;
    import java.lang.reflect.Array;
    import java.lang.reflect.Method;
    import java.util.ArrayList;
    import java.util.HashMap;
    import java.util.Hashtable;
    import java.util.LinkedHashMap;
    import java.util.LinkedHashSet;
    import java.util.LinkedList;
    import java.util.Map;
    import java.util.Set;
    import java.util.SortedMap;
    import java.util.TreeMap;
    import java.util.TreeSet;
    import java.util.Vector;
    import java.util.WeakHashMap;
    import java.util.regex.Pattern;
    import java.util.Iterator;
    public class TestNull {
    @SuppressWarnings("unchecked")
    public static void main(String args[]) throws Exception{
    char ch [][] = new char[10][10];
    System.out.println("char ch[]= " + isNull(ch));
    byte be [] = new byte[10];
    System.out.println("byte be[]= " + isNull(be));
    float[] ft = new float[10];
    System.out.println("float ft[]= " + isNull(ft));
    double ad[] = new double[10];
    System.out.println("double ad[]= " + isNull(ad));
    int ai[][][] = new int [10][10][10];
    System.out.println("int ai[]= " + isNull(ai));
    Object ob = null;
    System.out.println("Object= " + isNull(ob));
    String a [] =null;
    System.out.println("String a []= " + isNull(a));
    List aa = new List();
    System.out.println("List= " + isNull(aa));
    ArrayList aaa = new ArrayList();
    System.out.println("ArrayList= " + isNull(aaa));
    Map map = new HashMap();
    System.out.println("HashMap= " + isNull(map));
    String a2 [][][][] = new String[10][10][10][20];
    System.out.println("String a2 [][][][]= " + isNull(a2));
    HashMap map2 = new HashMap();
    System.out.println("HashMap= " + isNull(map2));
    Vector keys = new Vector();
    System.out.println("Vector= " + isNull(keys));
    Hashtable ht = new Hashtable();
    System.out.println("Hashtable= " + isNull(ht));
    LinkedList lt = new LinkedList();
    System.out.println("LinkedList= " + isNull(lt));
    TreeSet tt = new TreeSet();
    System.out.println("TreeSet= " + isNull(tt));
    Set ss = new TreeSet();
    System.out.println("TreeSet= " + isNull(ss));
    Iterator it = new ArrayList().iterator();
    System.out.println("Iterator= " + isNull(it));
    LinkedHashMap llp = new LinkedHashMap();
    System.out.println("LinkedHashMap= " + isNull(llp));
    LinkedHashSet llt = new LinkedHashSet();
    System.out.println("LinkedHashSet= " + isNull(llt));
    WeakHashMap wp =new WeakHashMap();
    System.out.println("WeakHashMap= " + isNull(wp));
    String sra = "’’,a,b,c";
    System.out.println(sra.split(",")[0]);
    System.out.println("sra= " + isNull(sra.split(",")[0]));
    SortedMap m= new TreeMap();
    System.out.println("SortedMap= " + isNull(m));
    }