版权声明:本文为博主原创文章,未经博主允许不得转载。 https://blog.csdn.net/BAStriver/article/details/83791956
1.将元素插入List的指定位置:
List<String> list = new ArrayList<String>();
list.add("a");
list.add("b");
list.add("c");
list.add("d");
list.add("e");
list.add(2, "f");
System.out.println(list); // [a, b, f, c, d, e]
2.对List<?>排序:
首先假设youz有这个bean : ColumnValue
public class ColumnValue implements Comparable<ColumnValue>{
private ColumnMeta column;
private Object value;
private boolean check = true;
public ColumnValue() {
}
public ColumnValue(ColumnMeta column, Object value) {
this(column, value, true);
}
public ColumnValue(ColumnMeta column, Object value, boolean check) {
this.value = value;
this.column = column;
this.check = check;
}
public ColumnMeta getColumn() {
return column;
}
public void setColumn(ColumnMeta column) {
this.column = column;
}
public Object getValue() {
return value;
}
public void setValue(Object value) {
this.value = value;
}
public boolean isCheck() {
return check;
}
public void setCheck(boolean check) {
this.check = check;
}
public ColumnValue clone() {
ColumnValue column = new ColumnValue();
column.setValue(this.value);
column.setColumn(this.column.clone());
return column;
}
public int hashCode() {
final int prime = 31;
int result = 1;
result = prime * result + ((column == null) ? 0 : column.hashCode());
result = prime * result + ((value == null) ? 0 : value.hashCode());
return result;
}
public boolean equals(Object obj) {
if (this == obj) return true;
if (obj == null) return false;
if (getClass() != obj.getClass()) return false;
ColumnValue other = (ColumnValue) obj;
if (column == null) {
if (other.column != null) return false;
} else if (!column.equals(other.column)) return false;
if (value == null) {
if (other.value != null) return false;
} else if (!value.equals(other.value)) return false;
return true;
}
@Override
public String toString() {
return "ColumnValue [column=" + column + ", value=" + value + "]";
}
@Override
public int compareTo(ColumnValue col) {
// TODO Auto-generated method stub
int flag = this.column.getName().compareTo(col.column.getName());
return flag;
}
}
对,shi实现这个接口 : Comparable<ColumnValue>
然后实现这个对比的方法 : compareTo 这里是根据name来排序。
调用排序:
List<ColumnValue> columns = new LinkedList<ColumnValue>();
Collections.sort(columns); // 排序