针对Model类的代码修剪器

直接用Mybatis Generator生成的Model类大概是这样的

package com.spldeolin.demoapp.po;

import java.util.Date;
import javax.persistence.*;

@Table(name = "a_table")
public class ATable {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;

    @Column(name = "inserted_at")
    private Date insertedAt;

    @Column(name = "updated_at")
    private Date updatedAt;

    @Column(name = "deleted_at")
    private Date deletedAt;

    @Column(name = "a_name")
    private String aName;

    /**
     * @return id
     */
    public Long getId() {
        return id;
    }

    /**
     * @param id
     */
    public void setId(Long id) {
        this.id = id;
    }

    /**
     * @return inserted_at
     */
    public Date getInsertedAt() {
        return insertedAt;
    }

    /**
     * @param insertedAt
     */
    public void setInsertedAt(Date insertedAt) {
        this.insertedAt = insertedAt;
    }

    /**
     * @return updated_at
     */
    public Date getUpdatedAt() {
        return updatedAt;
    }

    /**
     * @param updatedAt
     */
    public void setUpdatedAt(Date updatedAt) {
        this.updatedAt = updatedAt;
    }

    /**
     * @return deleted_at
     */
    public Date getDeletedAt() {
        return deletedAt;
    }

    /**
     * @param deletedAt
     */
    public void setDeletedAt(Date deletedAt) {
        this.deletedAt = deletedAt;
    }

    /**
     * @return a_name
     */
    public String getaName() {
        return aName;
    }

    /**
     * @param aName
     */
    public void setaName(String aName) {
        this.aName = aName;
    }
}

在项目配置了lombok的情况下，里面的getter和setter都是不必要的。同时，作为一个Model类，每一个的对象都是很有可能存入到Redis之类缓存里面的，所以为让每一个Model类都实现Serializable接口也是不错的注意。可以写一个“代码修剪器”应对这样的需求。

/**
 * 代码修剪器，对通过代码生成器生成代码，进行简化<br>
 * 这个工具类适合在Mybatis Generator使用完之后直接运行，不适合处理被开发人员修改的model类。
 *
 * @author Deolin
 */
public class CodeTrimmer {

    /**
     * 【1】model类所在包的绝对路径
     */
    private static final String MODEL_PACKAGE_ABSOLUTE_PATH =
            "";

    public static void main(String[] args) {
        /**
         * 【2】需要被处理的model类名，不填则处理所有
         */
        trimModels();
    }

    private static void trimModels(String... targetFilenames) {
        List<String> filenames = Arrays.asList(targetFilenames);
        // 遍历文件
        File folder = new File(MODEL_PACKAGE_ABSOLUTE_PATH);
        List<File> files = new ArrayList<>();
        interceptFiles(files, folder);
        for (File file : files) {
            if (filenames.size() != 0 && !filenames.contains(fileName(file))) {
                continue;
            }
            try {
                trimOneModel(file);
            } catch (Exception ignored) {}
        }
    }

    private static void interceptFiles(List<File> files, File folder) {
        for (File file : folder.listFiles()) {
            if (file.isDirectory()) {
                interceptFiles(files, file);
            } else if ("java".equals(fileExtension(file))) {
                files.add(file);
            } else {
                // nothing
            }
        }
    }

    private static void trimOneModel(File file) throws Exception {
        // 读java文件
        FileReader fr = new FileReader(file);
        BufferedReader br = new BufferedReader(fr);
        List<String> inputLines = new ArrayList<>();
        String tempLine;
        while ((tempLine = br.readLine()) != null) {
            inputLines.add(tempLine);
        }
        br.close();
        fr.close();
        // 读完毕，开始处理
        Collections.reverse(inputLines);
        List<String> outputLines = new ArrayList<>();
        boolean meetPublicClassEver = false;
        boolean meetImportEver = false;
        outputLines.add("}");
        for (String inputLine : inputLines) {
            // public class
            if (StringUtils.trimToEmpty(inputLine).startsWith("public class")) {
                outputLines.add("");
                outputLines.add("    private static final long serialVersionUID = 1L;");
                outputLines.add(addImplements(inputLine));
                addTableAnnouncement(inputLine, outputLines);
                addClassAnnotation(outputLines);
                addImport(outputLines);
                meetPublicClassEver = true;
                continue;
            }
            // @Table
            if (StringUtils.trimToEmpty(inputLine).startsWith("@Table")) {
                // 遇到@Table则不要
                continue;
            }
            // Getter, Setter 方法签名与方法体
            if (isMethodSignOrBody(inputLine)) {
                continue;
            }
            // 如果ignoreJavaDoc未被改变过（遇到类声明之前），且第一次遇到private，则都不再处理JavaDoc
            if (!meetPublicClassEver) {
                String lineContent = StringUtils.trimToEmpty(inputLine);
                if (!lineContent.startsWith("private") && !lineContent.startsWith("*/") &&
                        !lineContent.startsWith("*") && !lineContent.startsWith("/**") &&
                        !lineContent.equals("")) {
                    throw new RuntimeException("java文件中存在非getter、setter方法，跳过处理。");
                }
                if (lineContent.startsWith("private")) {
                    meetPublicClassEver = true;
                }
            }
            // Getter, Setter 方法注释
            if (!meetPublicClassEver && isJavaDoc(inputLine)) {
                continue;
            }
            outputLines.add(inputLine);
        }
        Collections.reverse(outputLines);
        // 处理完毕，开始写。
        FileWriter fw = new FileWriter(file);
        BufferedWriter bw = new BufferedWriter(fw);
        for (String outputLine : outputLines) {
            bw.write(outputLine + System.getProperty("line.separator"));
        }
        bw.close();
        fw.close();
    }

    private static boolean isMethodSignOrBody(String line) {
        line = StringUtils.trimToEmpty(line);
        if (StringUtils.startsWithIgnoreCase(line, "public")) {
            if (!StringUtils.startsWithIgnoreCase(line, "public class")) {
                return true;
            }
        }
        if (StringUtils.startsWithIgnoreCase(line, "return")) {
            return true;
        }
        if (StringUtils.startsWithIgnoreCase(line, "this.")) {
            return true;
        }
        if (StringUtils.startsWithIgnoreCase(line, "}")) {
            return true;
        }
        return false;
    }

    private static boolean isJavaDoc(String line) {
        line = StringUtils.trimToEmpty(line);
        if (StringUtils.startsWithIgnoreCase(line, "/**") || StringUtils.startsWithIgnoreCase(line, "*") ||
                StringUtils.startsWithIgnoreCase(line, "*/")) {
            return true;
        }
        return false;
    }

    private static void addClassAnnotation(List<String> lines) {
        lines.add("@NoArgsConstructor");
        lines.add("@EqualsAndHashCode");
        lines.add("@ToString");
        lines.add("@Setter");
        lines.add("@Getter");
    }

    private static void addImport(List<String> lines) {
        lines.add("import lombok.ToString;");
        lines.add("import lombok.Setter;");
        lines.add("import lombok.NoArgsConstructor;");
        lines.add("import lombok.Getter;");
        lines.add("import lombok.EqualsAndHashCode;");
        lines.add("import java.io.Serializable;");
    }

    private static String addImplements(String line) {
        line = StringUtils.stripEnd(line, "{");
        line += "implements Serializable {";
        return line;
    }

    private static void addTableAnnouncement(String line, List<String> lines) {
        String className = StringUtils.trimToEmpty(line).replace("public class ", "").replace(" {", "");
        String tableAnnouncement = "@Table(name = \"" + camelToUnderline(className) + "\")";
        lines.add(tableAnnouncement);
    }

    private static String fileName(File file) {
        String fileFullName = file.getName();
        return fileFullName.substring(0, fileFullName.lastIndexOf("."));
    }

    private static String fileExtension(File file) {
        String fileFullName = file.getName();
        return fileFullName.substring(fileFullName.lastIndexOf(".") + 1);
    }

    private static String camelToUnderline(String camelCaseName) {
        StringBuilder result = new StringBuilder();
        if (camelCaseName != null && camelCaseName.length() > 0) {
            result.append(camelCaseName.substring(0, 1).toLowerCase());
            for (int i = 1; i < camelCaseName.length(); i++) {
                char ch = camelCaseName.charAt(i);
                if (Character.isUpperCase(ch)) {
                    result.append("_");
                    result.append(Character.toLowerCase(ch));
                } else {
                    result.append(ch);
                }
            }
        }
        return result.toString();
    }

}

处理完的类中会有很多不必要的空行，只有在IDEA选中model包，Reformat Code即可。

最终效果是这样的。

package com.spldeolin.demoapp.po;

import java.io.Serializable;
import java.util.Date;
import javax.persistence.Column;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.Table;

import lombok.EqualsAndHashCode;
import lombok.Getter;
import lombok.NoArgsConstructor;
import lombok.Setter;
import lombok.ToString;

@Getter
@Setter
@ToString
@EqualsAndHashCode
@NoArgsConstructor
@Table(name = "a_table")
public class ATable implements Serializable {

    private static final long serialVersionUID = 1L;

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;

    @Column(name = "inserted_at")
    private Date insertedAt;

    @Column(name = "updated_at")
    private Date updatedAt;

    @Column(name = "deleted_at")
    private Date deletedAt;

    @Column(name = "a_name")
    private String aName;

}