<> Evaluate first : The function is very good , But I always feel it's a waste of time

* Introduce first pom rely on <dependency> <groupId>org.springframework.boot</groupId> <
artifactId>spring-boot-starter-test</artifactId> <scope>test</scope> </
dependency>
* code 1 public class MongoUser implements Serializable{ private static final
long serialVersionUID = 1L; @Id private String id; private String name; private
String age; public String getId() { return id; } public void setId(String id) {
this.id = id; } public String getName() { return name; } public void setName(
String name) { this.name = name; } public String getAge() { return age; } public
void setAge(String age) { this.age = age; } @Override public boolean equals(
Object o) { if (this == o) return true; if (o == null || getClass() != o.
getClass()) return false; MongoUser user = (MongoUser) o; return Objects.equals(
id, user.id) && Objects.equals(name, user.name) && Objects.equals(age, user.age)
; } @Override public int hashCode() { return Objects.hash(id, name, age); } }
* code 2 @RunWith(SpringRunner.class) @SpringBootTest @Transactional public class
ApplicationTests { @Autowired private RedisService redisService; @Autowired
private UserDao userDao; @Autowired private JdbcTemplate jdbcTemplate;
@Autowired private MongoTemplate mongoTemplate; @Test public void hello() {
System.out.println("hello world"); redisService.setObjectJSON("test", "1");
System.out.println(" Used redisservice"); User user = userDao.find("id=?", 1l).
first(); System.out.println(" A user name is printed out "+user.userName); List<Map<String,Object>>
queryForList= jdbcTemplate.queryForList("select id,user_name from c_user where
id<2"); for (Map<String, Object> map : queryForList) { Object object = map.get(
"id"); System.out.println(object); Object object2 = map.get("user_name"); System
.out.println(object2); } MongoUser mongoUser2 = new MongoUser(); mongoUser2.
setId("1"); mongoUser2.setName(" Xiao Ming "); mongoTemplate.insert(mongoUser2); List<
MongoUser> findAll = mongoTemplate.findAll(MongoUser.class); for (MongoUser
mongoUser: findAll) { System.out.println("id="+mongoUser.getId()); System.out.
println("id="+mongoUser.getName()); } } public static void main(String[] args) {
HashMap<String,Object> hashMap = new HashMap<String, Object>(); hashMap.put("a"
, 1); hashMap.put("b", 2); Set<String> keySet = hashMap.keySet(); for (String
string: keySet) { System.out.println(string); Object object = hashMap.get(string
); System.out.println(object); System.out.println("================"); } } }

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