Question

如何使用java在postgres数据库中插入数据？这是我正在执行的代码，它会抛出一个错误：

public static Result add() {
    response().setContentType("application/json");
    JsonNode val = request().body().asJson();
    System.out.println(val);
    ObjectNode result= new ObjectNode(val);
    String firstname=val.findPath("firstname").textValue();
    System.out.println(firstname);
    String lastname=val.findPath("lastname").textValue();
    System.out.println(lastname);
    result.put(firstname, 1);
    result.put(lastname, 2);
    System.out.println(result);
    Ebean.save(result);
    return ok(index.render("Record has been inserted"+user));
}

Answer 1

Play使用Ebean（默认情况下）作为使用JPA映射实体的持久性框架。有关详情，请参阅docs。因此，您只能持久保存JPA带注释的实体。您正在尝试保留Jackson ObjectNode对象，该对象显然不是JPA带注释的实体。

假设您要保留的是Person，您的代码将更改为以下内容：

应用程序/模型/ Person.java

package models;

import play.db.ebean.Model;

import javax.annotation.Generated;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.SequenceGenerator;
import javax.persistence.Id;

@Entity
public class Person extends Model {

    @Id
    @GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "person_seq_gen")
    @SequenceGenerator(name = "person_seq_gen", sequenceName = "person_id_seq")
    public Long id;

    public String firstName;
    public String lastName;

}

在您的控制器类中：

public static Result add() {
    JsonNode val = request().body().asJson();
    System.out.println(val);

    String firstname=val.findPath("firstname").textValue();
    System.out.println(firstname);
    String lastname=val.findPath("lastname").textValue();
    System.out.println(lastname);

    Person person = new Person();
    person.firstName = firstname;
    person.lastName = lastname;
    person.save();

    return ok(index.render("Record has been inserted"+person));
}

注意您还必须为Postgres配置jdbc驱动程序。 See here

此代码将保留您的＆＃34; person＆＃34;记录在一个名为“人物”的表中。

Answer 2

public static Result add() throws Exception {
    Myapps user = new Myapps();
    try {
        JsonNode requestBody = request().body().asJson();
         ObjectMapper mapper = new ObjectMapper();

                     ObjectReader reader = mapper.readerForUpdating(user);

                     user = reader.readValue(requestBody);
        user.save();

    } catch (Exception e) {
        e.printStackTrace();
    }

    return ok(Json.toJson("inserted value is" + user));
}

使用Java在PostGRES上插入数据

2 个答案: