数据库表部分更新

对应的Mapper类

public interface WorksDetailDao extends BaseMapper<WorksDetail> {
    void addAll(List<WorksDetail> list);

    void updateAll(@Param(value = "list") List<WorksDetail> items);

}

对应的addAll的XML文件

    <insert id="addAll" parameterType="java.util.List" useGeneratedKeys="true" keyProperty="id">
        Insert Into `works_detail` (
        `source_id`
        ,`platform`
        )
        Values
        <foreach collection="list" item="item" index="index" separator=",">
            (
            #{item.sourceId}
            ,#{item.platform}
            )
        </foreach>
    </insert>

对应的updateAll的XML文件

<update id="updateAll" parameterType="java.util.List">
        Update `works_detail`
        <trim prefix="set" suffixOverrides=",">
            <trim prefix="`author`=case" suffix="else `author` end,">
                <foreach collection="list" item="item" index="index">
                    <if test="item.author!=null">
                        when `id`=#{item.id} then #{item.author}
                    </if>
                </foreach>
            </trim>
            <trim prefix="`title`=case" suffix="else `title` end,">
                <foreach collection="list" item="item" index="index">
                    <if test="item.title!=null">
                        when `id`=#{item.id} then #{item.title}
                    </if>
                </foreach>
            </trim>
        </trim>
        where
        <foreach collection="list" separator="or" item="item" index="index">
            `id`=#{item.id}
        </foreach>
    </update>

根据类生成xml语句代码

public class JavaBeanToTrimXml {
    public static String generateUpdateTrimsForClass(Class<?> clazz) {
        StringBuilder sb = new StringBuilder();

        List<Field> fields = getAllFields(clazz);
        for (Field field : fields) {
            if (!field.getName().equals("id")) { // Assuming "id" is not supposed to be updated
                String fieldName = field.getName();
                String columnName = fieldName;

                sb.append("\n\t<!-- ").append(camelToUnderscore(fieldName)).append(" -->\n");
                sb.append("\t<trim prefix=\"`").append(camelToUnderscore(fieldName)).append("`=CASE\" suffix=\"ELSE `").append(camelToUnderscore(fieldName)).append("` END,\" >\n");
                sb.append("\t\t<foreach collection=\"list\" item=\"item\" index=\"index\">\n");
                sb.append("\t\t\t<if test=\"item.").append(fieldName).append(" != null\">\n");
                sb.append("\t\t\t\tWHEN `id` = #{item.id} THEN #{item.").append(fieldName).append("}\n");
                sb.append("\t\t\t</if>\n");
                sb.append("\t\t</foreach>\n");
                sb.append("\t</trim>");
            }
        }

        return sb.toString();
    }

    private static List<Field> getAllFields(Class<?> clazz) {
        List<Field> fields = new ArrayList<>();
        while (clazz != null) {
            for (Field field : clazz.getDeclaredFields()) {
                fields.add(field);
            }
            clazz = clazz.getSuperclass();
        }
        return fields;
    }
    /**
     * 将驼峰命名风格的字符串转换为下划线分隔的小写字母字符串。
     *
     * @param camelCaseString 驼峰命名风格的字符串
     * @return 下划线分隔的小写字母字符串
     */
    public static String camelToUnderscore(String camelCaseString) {
        StringBuilder sb = new StringBuilder(camelCaseString.length());
        for (int i = 0; i < camelCaseString.length(); i++) {
            char c = camelCaseString.charAt(i);
            if (Character.isUpperCase(c)) {
                if (i > 0 && !Character.isUpperCase(camelCaseString.charAt(i - 1))) {
                    sb.append('_');
                }
                sb.append(Character.toLowerCase(c));
            } else {
                sb.append(c);
            }
        }
        return sb.toString();
    }

    private static String convertFieldNameToColumnName(String fieldName) {
        // Perform any necessary conversion from field name to column name.
        // For simplicity, here we assume they are the same.
        return fieldName;
    }

    public static void main(String[] args) {
        String generatedTrims = generateUpdateTrimsForClass(GrainPortraitVo.class);
        System.out.println(generatedTrims);
    }
}

获取java的所有sql字段

public class JavaBeanToTableFeild {
    public static String generateFieldList(Class<?> clazz) {
        List<String> fieldNames = new ArrayList<>();

        List<Field> fields = getAllFields(clazz);
        for (Field field : fields) {
            fieldNames.add("\"" + camelToUnderscore(field.getName()) + "\"" + "\n");
        }

        return String.join(", ", fieldNames);
    }

    /**
     * 将驼峰命名风格的字符串转换为下划线分隔的小写字母字符串。
     *
     * @param camelCaseString 驼峰命名风格的字符串
     * @return 下划线分隔的小写字母字符串
     */
    public static String camelToUnderscore(String camelCaseString) {
        StringBuilder sb = new StringBuilder(camelCaseString.length());
        for (int i = 0; i < camelCaseString.length(); i++) {
            char c = camelCaseString.charAt(i);
            if (Character.isUpperCase(c)) {
                if (i > 0 && !Character.isUpperCase(camelCaseString.charAt(i - 1))) {
                    sb.append('_');
                }
                sb.append(Character.toLowerCase(c));
            } else {
                sb.append(c);
            }
        }
        return sb.toString();
    }
    private static List<Field> getAllFields(Class<?> clazz) {
        List<Field> fields = new ArrayList<>();
        while (clazz != null) {
            for (Field field : clazz.getDeclaredFields()) {
                fields.add(field);
            }
            clazz = clazz.getSuperclass();
        }
        return fields;
    }

    public static void main(String[] args) {
        String fieldList = generateFieldList(GrainPortraitVo.class);
        System.out.println(fieldList);
    }
}