java知识手册

• 1.java8 list排序——通过指定元素排序
  • 1.1 排序方法
  • 1.2 测试示例
• 2.java8 list去重——通过指定元素去重
  • 2.1 去重方法
  • 2.2 测试示例
• 3.枚举配置类
  • 3.1 枚举类
  • 3.2 测试示例
• 4.返回实体类配置

1.java8 list排序——通过指定元素排序

1.1 排序方法

  tbLabelList = tbLabelList.stream().sorted(Comparator.comparing(TbLabel::getUserAnswerTimes).reversed()).collect(Collectors.toList());

1.2 测试示例

TbLabel:

public class TbLabel {
     

    /** detail_id - 对应具体文章的id*/
    private Integer detailId;

    /** school_id - 提供给哪一个高校使用*/
    private Integer schoolId;
    /**标签对应的用户回复频率**/
    private Double userAnswerTimes;

}

测试：

 List<TbLabel> tbLabelList=new ArrayList<>();
        TbLabel tbLabel1=new TbLabel();
        tbLabel1.setUserAnswerTimes(2.01);
        tbLabel1.setSchoolId(1);
        TbLabel tbLabel2=new TbLabel();
        tbLabel2.setUserAnswerTimes(2.121);
        tbLabel2.setSchoolId(1);
        TbLabel tbLabel3=new TbLabel();
        tbLabel3.setUserAnswerTimes(3.01);
        tbLabel3.setSchoolId(1);
        tbLabelList.add(tbLabel1);
        tbLabelList.add(tbLabel2);
        tbLabelList.add(tbLabel3);
         tbLabelList = tbLabelList.stream().sorted(Comparator.comparing(TbLabel::getUserAnswerTimes).reversed()).collect(Collectors.toList());//根据UserAnswerTimes倒序排列

2.java8 list去重——通过指定元素去重

2.1 去重方法

 tbLabelList = tbLabelList.stream().collect(
                collectingAndThen(toCollection(() -> new TreeSet<>(comparingLong(TbLabel::getDetailId))), ArrayList::new));

2.2 测试示例

TbLabel:

public class TbLabel {
     

    /** detail_id - 对应具体文章的id*/
    private Integer detailId;

    /** school_id - 提供给哪一个高校使用*/
    private Integer schoolId;
    /**标签对应的用户回复频率**/
    private Double userAnswerTimes;

}

测试：

        List<TbLabel> tbLabelList=new ArrayList<>();
        TbLabel tbLabel1=new TbLabel();
        tbLabel1.setUserAnswerTimes(2.01);
        tbLabel1.setDetailId(1);
        TbLabel tbLabel2=new TbLabel();
        tbLabel2.setUserAnswerTimes(2.121);
        tbLabel2.setDetailId(1);
        TbLabel tbLabel3=new TbLabel();
        tbLabel3.setUserAnswerTimes(3.01);
        tbLabel3.setDetailId(2);
        tbLabelList.add(tbLabel1);
        tbLabelList.add(tbLabel2);
        tbLabelList.add(tbLabel3);
         tbLabelList = tbLabelList.stream().sorted(Comparator.comparing(TbLabel::getUserAnswerTimes).reversed()).collect(Collectors.toList());//根据DetailId去重

3.枚举配置类

3.1 枚举类

 public enum ContentConfig {
     
    /**infoType 消息类型（0-待回复；1-用户审批;2-互助圈审批;3-创建学校审批）**/
    INFOTYPE_ANSWER(0),
    INFOTYPE_USER_APPROVE(1),
    INFOTYPE_HELPCIRCLE_APPROVE(2),
    INFOTYPE_CREATESCHOOL_APPROVE(3);
    private final int value;

    ContentConfig(int value) {
     
        this.value = value;
    }

    public int getValue() {
     
        return value;
    }
}

3.2 测试示例

 /**
     * 使用示例
     * @param args
     */
    public static void main(String[] args) {
     
        System.out.println(ContentConfig.INFOTYPE_ANSWER.getValue());
    }

4.返回实体类配置

package com.cn.own.model;

import com.fasterxml.jackson.annotation.JsonInclude;
import org.springframework.util.ObjectUtils;

@JsonInclude(JsonInclude.Include.NON_NULL)
public class BaseResult {
     
    private static final long serialVersionUID = 1L;
    private Integer code;
    private String msg;
    private Object data;
    private Long count;

    public BaseResult() {
     
    }

    public BaseResult(Integer code, String msg, Object data, Long count) {
     
        this.code = code;
        this.msg = msg;
        this.data = data;
        this.count = count;
    }

    public void markSuccess(String msg, Object data, Long count) {
     
        this.code = 200;
        this.msg = msg;
        this.data = data;
        this.count = count;
    }

    public void markSysError(String msg) {
     
        this.code = 500;
        this.msg = msg;
    }

    public void markWarning(String msg) {
     
        this.code = 0;
        this.msg = msg;
    }

    public boolean checkSuccess() {
     
        return ObjectUtils.isEmpty(this.getCode()) && 200 == this.getCode();
    }

    public boolean checkSuccessWData() {
     
        return this.checkSuccess() && ObjectUtils.isEmpty(this.getData());
    }

    public Integer getCode() {
     
        return this.code;
    }

    public void setCode(Integer code) {
     
        this.code = code;
    }

    public String getMsg() {
     
        return this.msg;
    }

    public void setMsg(String msg) {
     
        this.msg = msg;
    }

    public Object getData() {
     
        return this.data;
    }

    public void setData(Object data) {
     
        this.data = data;
    }

    public Long getCount() {
     
        return this.count;
    }

    public void setCount(Long count) {
     
        this.count = count;
    }

    public String toString() {
     
        return "BaseResult [code=" + this.code + ", msg=" + this.msg + ", data=" + this.data + ", count=" + this.count + "]";
    }

}

用法：

   @RequestMapping(value = "clearDatabase_userINfo")
    @ResponseBody
    public BaseResult clearDatabase_userINfo(@RequestParam(value = "userId") String userId,
                                             HttpServletResponse response, HttpServletRequest request) {
     
        response.setHeader("Access-Control-Allow-Origin", request.getHeader("Origin"));
        response.setHeader("Access-Control-Allow-Credentials", "true");// 允许服务器向浏览器跨域响应时更改浏览器（客户端）的cookie
        BaseResult baseResult=new BaseResult();
        try {
     

            Integer re = tMapper.deleteUserInfo(Integer.valueOf(userId));
            baseResult.markSuccess("清除成功",re,null);
        } catch (Exception e) {
     
            e.printStackTrace();
            baseResult.markSysError("清除失败");
        }
        return baseResult;
    }