树状日志拼装工具, 用于日志跟踪记录递归结构

Test.java

public class Test {
  public static void main(String... args) {
      TreeLog log = new TreeLog("test");
      log.log("第一层");
      TreeLog log1 = log.addChild("test1");
      log1.log("第二层");
      TreeLog log2 = log1.addChild("test2");
      log2.log("第三层");
      TreeLog log3 = log.addChild("test3");
      log3.log("又一个第二层");
      TreeLog log4 = log2.addChild("test4");
      log4.log("第四层");
      TreeLog log5 = log1.addChild("test5");
      log5.log("又一个第三层");
      TreeLog log6 = log2.addChild("test6");
      log6.log("又一个第四层");
      TreeLog log7 = log.addChild("test7");
      log7.log("再一个第二层");
      System.out.println(log);
  }
}

TreeLog.java

package test;

import java.io.Serializable;
import java.util.ArrayList;
import java.util.HashSet;
import java.util.List;
import java.util.Set;

public class TreeLog implements Serializable {

    private static final long   serialVersionUID = 8786588317154681976L;

    private static final String END_CON          = "\u2514\u2500";
    private static final String CON              = "\u251c\u2500";
    private static final String IDENT            = "  ";
    private static final String V_IDENT          = "\u2502 ";

    // 当前层节点标识
    private String              currentNodeName;
    // 当前层节点信息内容
    private StringBuilder       currentNodeMsg;
    // 下层子节点
    private List<TreeLog>       children;

    public TreeLog(String currentNodeName) {
        this.currentNodeName = currentNodeName;
    }

    public void setCurrentNodeName(String currentNodeName) {
        this.currentNodeName = currentNodeName;
    }

    public TreeLog log(Object msg) {
        if (this.currentNodeMsg == null)
            this.currentNodeMsg = new StringBuilder();
        if (msg != null)
            this.currentNodeMsg.append(msg);
        return this;
    }

    public TreeLog addChild(String name) {
        if (this.children == null)
            this.children = new ArrayList<TreeLog>();
        TreeLog ret = new TreeLog(name);
        this.children.add(ret);
        return ret;
    }

    @Override
    public String toString() {
        StringBuilder sb = new StringBuilder();
        genLog(sb, this, 0, false, new HashSet<Integer>());
        return sb.toString();
    }

    private void genLog(StringBuilder sb, TreeLog cur, int level, boolean hasNextSibling,
                        Set<Integer> vertIdentIdxes) {
        // 生成本层内容的行
        if (level == 1) {
            sb.append(IDENT);
        } else if (level > 1) {
            for (int i = 0; i < level * 2 - 1; i++)
                if (vertIdentIdxes.contains(i)) {
                    sb.append(V_IDENT);
                } else {
                    sb.append(IDENT);
                }

        }
        if (level != 0)
            if (hasNextSibling)
                sb.append(CON);
            else
                sb.append(END_CON);

        sb.append(cur.currentNodeName);
        if (cur.currentNodeMsg != null)
            sb.append(": ").append(cur.currentNodeMsg);
        sb.append('\n');

        Set<Integer> childrenVerts = new HashSet<Integer>(vertIdentIdxes);
        // 若当前节点后面还有平级节点，则需要通知当前节点的子节点生成竖线的位置
        if (hasNextSibling)
            childrenVerts.add(level * 2 - 1);
        // 生成所有children内容，每个child占用一行, 依顺序排在后面
        if (cur.children != null && !cur.children.isEmpty()) {
            for (int i = 0; i < cur.children.size(); i++) {
                TreeLog c = cur.children.get(i);
                genLog(sb, c, level + 1, i != cur.children.size() - 1, childrenVerts);
            }
        }
    }

}

输出.md

test: 第一层
  ├─test1: 第二层
  │   ├─test2: 第三层
  │   │   ├─test4: 第四层
  │   │   └─test6: 又一个第四层
  │   └─test5: 又一个第三层
  ├─test3: 又一个第二层
  └─test7: 再一个第二层