ArrayList的排序方法 sort( )的使用，arraylistsort

ArrayList的排序方法 sort( )的使用，arraylistsort

    ArrayList 中有一个用来排序的方法：sort( )。一般我们想对数组进行按某个规则排序的时候可以使用它比较方便。
    首先定义一个对象类 User package hlm.com.list;
import java.io.Serializable;import java.sql.Date;

public class User implements Serializable{        private static final long serialVersionUID = -1078433404507796595L;    private Integer id ;    private String userCode ;    private String userName ;    private Integer sex ;    private String token ;    private Date createTime ;    private Integer tokenType ;    private String password ;        public User(){            }    public User(Integer  id ,String userCode, String userName ,Integer sex , String password ){        this.id = id;        this.userCode = userCode;        this.userName = userName;        this.sex = sex;        this.password = password;    }    public String toString(){        return "id:"+id+",userName:"+userName;            }    public Integer getId() {        return id;    }    public void setId(Integer id) {        this.id = id;    }

    public Integer getSex() {        return sex;    }    public void setSex(Integer sex) {        this.sex = sex;    }    public String getToken() {        return token;    }    public void setToken(String token) {        this.token = token;    }
    public String getUserCode() {        return userCode;    }    public void setUserCode(String userCode) {        this.userCode = userCode;    }    public String getUserName() {        return userName;    }    public void setUserName(String userName) {        this.userName = userName;    }    public Date getCreateTime() {        return createTime;    }    public void setCreateTime(Date createTime) {        this.createTime = createTime;    }    public Integer getTokenType() {        return tokenType;    }    public void setTokenType(Integer tokenType) {        this.tokenType = tokenType;    }    public String getPassword() {        return password;    }    public void setPassword(String password) {        this.password = password;    }    }

    下面是具体使用的demopackagehlm.com.list;import java.util.ArrayList;importjava.util.Comparator;import java.util.List;public class TestArrayList {     public static void main(String[] args) {                      List<User> userList = new ArrayList<User>();           buildData(userList);           for(User u : userList){                System.out.println(u.toString());           }           System.out.println("<-----------我是华丽的分割线------------>");           userList.sort(new Comparator<User>(){                @Override                public int compare(User arg0, User arg1) {                     //这里是根据ID来排序，所以它为空的要剔除掉                     if(arg0.getId()==null || arg1.getId()==null) return 0;                                          return arg0.getId().compareTo(arg1.getId());//这是顺序                }                          });             for(User u : userList){                System.out.println(u.toString());           }     }     public static void buildData(List<User> userList){           if(userList == null){                userList = new ArrayList<User>();           }           User u1 = new User((Integer)1 ,"1+1", "小明" ,(Integer)0 , "123456");           User u2 = new User((Integer)2 ,"1+2", "小红" ,(Integer)1 , "123456");           User u3 = new User((Integer)3 ,"1+3", "小转" ,(Integer)0 , "123456");           User u4 = new User((Integer)4 ,"1+4", "小黑" ,(Integer)1 , "654321");           User u5 = new User((Integer)5 ,"1+5", "小兵" ,(Integer)0 , "666666");           User u6 = new User((Integer)6,"1+6", "小太阳" ,(Integer)1 , "888888");           userList.add(u5);           userList.add(u3);           userList.add(u2);           userList.add(u1);           userList.add(u4);           userList.add(u6);     }}
    输出结果为：id:5,userName:小兵id:3,userName:小转id:2,userName:小红id:1,userName:小明id:4,userName:小黑id:6,userName:小太阳<-----------我是华丽的分割线------------>id:1,userName:小明id:2,userName:小红id:3,userName:小转id:4,userName:小黑id:5,userName:小兵id:6,userName:小太阳

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20180627

今晚打球运动去了，所以内容不多，但这是我今天代码中遇到的东西，下次将进行其实现分析！