生成SQL查询语句

/** * 使用StringJoiner构建插入Sql语句 * @param fields String[] * @return String */public String buildSelectSql(String[] fields) {    StringJoiner stringJoiner = new StringJoiner(", ","SELECT "," FROM "+this.tableName);    for (String field: fields) {        stringJoiner.add(field);    }    return stringJoiner.toString();}

调用语句

/** * 获得select的sql */private static void _fetchSelectSql() {    SqlBuilder sqlBuilder = new SqlBuilder("employee");    String[] fieldArr = {"name", "position", "salary"};    String sql = sqlBuilder.buildSelectSql(fieldArr);    System.out.println("select sql="+sql);    String s = "SELECT name, position, salary FROM employee";    String testSqlRes = s.equals(sql) ? "测试成功" : "测试失败";    System.out.println("testSqlRes="+testSqlRes);}