如何正确使用Hutool和Guava这两个丰富的工具集，自己学习测试，样例

一、Hutool 关于数据库的操作示例

1.1 连接数据库：加载 config/db.setting

#===================================================================
# 数据库配置文件样例
# DsFactory默认读取的配置文件是config/db.setting
# db.setting的配置包括两部分：基本连接信息和连接池配置信息。
# 基本连接信息所有连接池都支持，连接池配置信息根据不同的连接池，连接池配置是根据连接池相应的配置项移植而来
#===================================================================

## 打印SQL的配置
# 是否在日志中显示执行的SQL，默认false
showSql = true
# 是否格式化显示的SQL，默认false
formatSql = true
# 是否显示SQL参数，默认false
showParams = true
# 打印SQL的日志等级，默认debug
sqlLevel = debug

[mysql]
url = jdbc:mysql://localhost:3306/proce?useSSL=false # 这里指定数据库
user = root
pass = root      

这里是测试model的建表语句和对应Model类

CREATE TABLE `user` (
  `id` int(11) DEFAULT NULL,
  `age` int(11) DEFAULT NULL,
  `name` varchar(20) DEFAULT NULL,
  `birthday` date DEFAULT NULL,
  `gender` varchar(2) DEFAULT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;      

@Data
public class User {

  private Integer id;

  private String name;

  private int age;

  private String birthday;

  private boolean gender;
}      

1.1 测试 MetaUtil

public class MetaUtilTest {
  DataSource ds = DSFactory.get("mysql"); // 加载 Mysql 数据库
  @Test
  public void getTablesTest() {
    List<String> tables = MetaUtil.getTables(ds);
  }
  @Test
  public void getTableMetaTest() {
    Table table = MetaUtil.getTableMeta(ds, "user");
  }
}      

返回数据

tables = [Atest, author, book, city, state, user]      

table  = {
"pkNames": [],
"columns": [
  {
    "size": 10,
    "isNullable": true,
    "name": "id",
    "typeName": "INT",
    "comment": "",
    "type": 4,
    "tableName": "user"
  },
  {
    "size": 20,
    "isNullable": true,
    "name": "name",
    "typeName": "VARCHAR",
    "comment": "",
    "type": 12,
    "tableName": "user"
  },
  {
    "size": 10,
    "isNullable": true,
    "name": "birthday",
    "typeName": "DATE",
    "comment": "",
    "type": 91,
    "tableName": "user"
  },
  {
    "size": 2,
    "isNullable": true,
    "name": "gender",
    "typeName": "VARCHAR",
    "comment": "",
    "type": 12,
    "tableName": "user"
  }
    ],
"comment": "",
"tableName": "user"
}      

1.2 conditionTest

@Test
  public void toStringTest() {
    Condition c1 = new Condition("name", null);
    System.out.println(c1);
    Condition c2 = new Condition("birthday", "!= null");
    System.out.println(c2);
    Condition c3 = new Condition("name", "= zhangsan");
    System.out.println(c3);
    Condition c4 = new Condition("name", "like %aaa");
    System.out.println(c4);
    Condition c5 = new Condition("id", "in 1,2,3");
    System.out.println(c5);
    Condition c6 = new Condition("age", "between 12 and 13");
    System.out.println(c6);
  }      

控制台输出为，默认条件占位符为 True

name IS NULL
birthday IS NOT NULL
name = ?
name LIKE ?
id IN (?,?,?)
age BETWEEN ? AND ?      

还有关于条件占位符的开启与关闭，这里指定为关闭

@Test
  public void toStringNoPlaceHolderTest() {
    Condition conditionNull = new Condition("user", null);
    conditionNull.setPlaceHolder(false);
    System.out.println(conditionNull);

    Condition conditionNotNull = new Condition("user", "!= null");
    conditionNotNull.setPlaceHolder(false);
    System.out.println(conditionNotNull);

    Condition conditionEquals = new Condition("user", "= zhangsan");
    conditionEquals.setPlaceHolder(false);
    System.out.println(conditionEquals);

    Condition conditionLike = new Condition("user", "like %aaa");
    conditionLike.setPlaceHolder(false);
    System.out.println(conditionLike);

    Condition conditionIn = new Condition("user", "in 1,2,3");
    conditionIn.setPlaceHolder(false);
    System.out.println(conditionIn);

    Condition conditionBetween = new Condition("user", "between 12 and 13");
    conditionBetween.setPlaceHolder(false);
    System.out.println(conditionBetween);
  }      

控制台输出为，和上面的输出比较一下区别

user IS NULL
user IS NOT NULL
user = zhangsan
user LIKE %aaa
user IN (1,2,3)
user BETWEEN 12 AND 13      

1.3 SqlBuilder测试

@Test
  public void queryNullTest() {
    SqlBuilder builder = SqlBuilder.create().select().from("user").where(new Condition("name", "= null"));
    System.out.println(builder);
    
    SqlBuilder builder2 = SqlBuilder.create().select().from("user").where(new Condition("name", "is null"));
    System.out.println(builder2);

    SqlBuilder builder3 = SqlBuilder.create().select().from("user").where(LogicalOperator.OR, new Condition("name", "!= null"),new Condition("name","like%as"));
    System.out.println(builder3);

    SqlBuilder builder4 = SqlBuilder.create().select().from("user").where(LogicalOperator.AND, new Condition("name", "is not null"),new Condition("id", "in 12,13,14"));
    System.out.println(builder4);
  }      

控制台输出为

SELECT * FROM user WHERE name IS NULL
SELECT * FROM user WHERE name IS NULL
SELECT * FROM user WHERE name IS NOT NULL OR name = ?
SELECT * FROM user WHERE name IS NOT NULL AND id IN (?,?,?)      

下一篇，基于Hutool包的的增删改查操作