Java Collections.sort 排序发生异常时结果是？

小咪咪 2021-09-25 02:14 414阅读 0赞

**抛出异常时，异常的元素会放到末尾（不再比较，不再往后按照新的属性比较。异常的元素依然存在） **

package com.company;
    
    import java.util.ArrayList;
    import java.util.Collections;
    import java.util.Comparator;
    import java.util.List;
    
    /**
     * @Author you guess
     * @Date 2021/1/8 11:05
     * @Version 1.0
     * @Desc
     */
    
    
    class Mobile {
    
        private String length;
        private String name;
    
        public Mobile(String length, String name) {
            this.length = length;
            this.name = name;
        }
    
    
        public String getLength() {
            return length;
        }
    
        public void setLength(String length) {
            this.length = length;
        }
    
        public String getName() {
            return name;
        }
    
        public void setName(String name) {
            this.name = name;
        }
    
        @Override
        public String toString() {
            return "Mobile{" +
                    "length=" + length +
                    ", name='" + name + '\'' +
                    '}';
        }
    }
    
    public class Main28 {
        public static void main(String[] args) {
            List<Mobile> list = new ArrayList<>();
            list.add(new Mobile("12", "xiaomi1"));
            list.add(new Mobile("13", "apple"));
            list.add(new Mobile("12", "xiaomi2"));
            list.add(new Mobile("9", "huawei"));
            list.add(new Mobile("8", "oppo"));
            list.add(new Mobile(null, "vivo2"));
            list.add(new Mobile(null, "vivo1"));
            list.add(new Mobile("", "vivo1"));
            list.add(new Mobile("", "vivo3"));
    
            Collections.sort(list, new Comparator<Mobile>() {
                @Override
                public int compare(Mobile o1, Mobile o2) {
                    try {
                        int lengthSeq = 0;
                        lengthSeq = Long.valueOf(o1.getLength()).compareTo(Long.valueOf(o2.getLength()));
                        if (lengthSeq == 0) {
                            return Integer.compare(o1.getName().compareTo(o2.getName()), 0);
                        }
                        return lengthSeq;
                    } catch (Exception e) {
                        e.printStackTrace();
                        System.err.println("sort err111" + "000000000000");
                    }
                    return 0;
                }
            });
    
            for (Mobile ele : list) {
                System.out.println(ele.toString());
            }
            //会抛出异常，但是转为Long异常的记录会放到末尾（不再比较，不再往后按照新的属性比较）
    
    //        Mobile{length=8, name='oppo'}
    //        Mobile{length=9, name='huawei'}
    //        Mobile{length=12, name='xiaomi1'}
    //        Mobile{length=12, name='xiaomi2'}
    //        Mobile{length=13, name='apple'}
    //        Mobile{length=null, name='vivo2'}
    //        Mobile{length=null, name='vivo1'}
    //        Mobile{length=, name='vivo1'}
    //        Mobile{length=, name='vivo3'}
    
    
        }//main
    }

注意看输出的结果！！

................
    java.lang.NumberFormatException: For input string: ""
    	at java.lang.NumberFormatException.forInputString(NumberFormatException.java:65)
    	at java.lang.Long.parseLong(Long.java:601)
    	at java.lang.Long.valueOf(Long.java:803)
    	at com.company.Main28$1.compare(Main28.java:70)
    	at com.company.Main28$1.compare(Main28.java:65)
    	at java.util.TimSort.binarySort(TimSort.java:296)
    	at java.util.TimSort.sort(TimSort.java:221)
    	at java.util.Arrays.sort(Arrays.java:1512)
    	at java.util.ArrayList.sort(ArrayList.java:1462)
    	at java.util.Collections.sort(Collections.java:177)
    	at com.company.Main28.main(Main28.java:65)
    sort err111000000000000
    java.lang.NumberFormatException: For input string: ""
    	at java.lang.NumberFormatException.forInputString(NumberFormatException.java:65)
    	at java.lang.Long.parseLong(Long.java:601)
    	at java.lang.Long.valueOf(Long.java:803)
    	at com.company.Main28$1.compare(Main28.java:70)
    	at com.company.Main28$1.compare(Main28.java:65)
    	at java.util.TimSort.binarySort(TimSort.java:296)
    	at java.util.TimSort.sort(TimSort.java:221)
    	at java.util.Arrays.sort(Arrays.java:1512)
    	at java.util.ArrayList.sort(ArrayList.java:1462)
    	at java.util.Collections.sort(Collections.java:177)
    	at com.company.Main28.main(Main28.java:65)
    sort err111000000000000
    Mobile{length=8, name='oppo'}
    Mobile{length=9, name='huawei'}
    Mobile{length=12, name='xiaomi1'}
    Mobile{length=12, name='xiaomi2'}
    Mobile{length=13, name='apple'}
    Mobile{length=null, name='vivo2'}
    Mobile{length=null, name='vivo1'}
    Mobile{length=, name='vivo1'}
    Mobile{length=, name='vivo3'}

jdk1.8