我正在尝试在Spring启动应用程序启动时设置H2数据库.我在application.properties中配置了数据库:
spring.datasource.url = jdbc:h2:file:~/testdb
spring.datasource.username = sa
spring.datasource.password = sa
spring.datasource.driverClassName = org.h2.Driver
Application.java文件:
@Configuration
@ComponentScan
@EnableAutoConfiguration
public class Application {
public static void main(String[] args) {
SpringApplication.run(Application.class, args);
CreateH2Database createH2Database = new CreateH2Database();
createH2Database.create();
}
}
CreateH2Database.java:
public class CreateH2Database {
private Logger log = Logger.getLogger(CreateH2Database.class);
@Autowired
protected JdbcTemplate jdbcTemplate;
public void create() {
log.info("Creating H2 Database");
createUsers();
}
private void createUsers() {
log.info("Creating users table");
jdbcTemplate.execute("create table if not exists users (id serial, first_name varchar(255), last_name varchar(255))");
String[] …当我尝试使用 Maven 编译项目时，出现以下错误：
[ERROR] Failed to execute goal org.apache.maven.plugins:maven-compiler-plugin:3.1:compile (default-compile) on project webserverlog: Compilation failure
[ERROR] No compiler is provided in this environment. Perhaps you are running on a JRE rather than a JDK?
[ERROR] -> [Help 1]
org.apache.maven.lifecycle.LifecycleExecutionException: Failed to execute goal org.apache.maven.plugins:maven-compiler-plugin:3.1:compile (default-compile) on project webserverlog: Compilation failure
No compiler is provided in this environment. Perhaps you are running on a JRE rather than a JDK?
我的 JAVA_HOME 指向 JDK：
$ echo $JAVA_HOME
/System/Library/Frameworks/JavaVM.framework/Versions/CurrentJDK/Home
$ $JAVA_HOME/bin/javac -version
javac …我在argument mismatch; Long cannot be converted to Example<S>下面的代码中收到了 findOne 调用：
public Optional<AuditEvent> find(Long id) {
return Optional.ofNullable(persistenceAuditEventRepository.findOne(id))
.map(auditEventConverter::convertToAuditEvent);
}
上面的代码正在转换为 Spring 5 和 Spring Boot 2。它在原始 Spring 4 和 Spring Boot 1 应用程序中运行良好。
任何想法我需要将上述代码转换为什么？
JHipster 5(使用Spring Boot 2)可以玩吗？我注意到在发行说明中提到了关于JHipster 5的工作,但是看不到有关如何安装/运行5的"预览"版本的任何信息.
我需要PointQuadTree在启动时使用带有构造函数参数的Spring Boot 初始化以下类,并使该对象在整个应用程序中可用.构造函数参数'minX,maxX,...'需要来自application.properties文件.
PointQuadTree
public class PointQuadTree<T extends PointQuadTree.Item> {
private final Bounds mBounds;
public PointQuadTree(double minX, double maxX, double minY, double maxY) {
this(new Bounds(minX, maxX, minY, maxY));
}
...
}
边界
public class Bounds {
public final double minX;
public final double minY;
public final double maxX;
public final double maxY;
public final double midX;
public final double midY;
public Bounds(double minX, double maxX, double minY, double maxY) {
this.minX = minX;
this.minY = minY;
this.maxX …我正在尝试转换Java方法：
private <T> Callable<T> createCallable(final Callable<T> task) {
return () -> {
try {
return task.call();
} catch (Exception e) {
handle(e);
throw e;
}
};
}
从以下Java文件ExceptionHandlingAsyncTaskExecutor.java进入Kotlin。
该代码使用IntelliJ IDEA自动转换为：
private fun <T> createCallable(task: Callable<T>): Callable<T> {
return {
try {
return task.call()
} catch (e: Exception) {
handle(e)
throw e
}
}
}
这是不正确的。但是我必须考虑应该采用哪种正确的实现方式。有任何想法吗？
我正在尝试将以下Spring Security代码从Java转换为Kotlin.
Java的:
Collection<? extends GrantedAuthority> authorities =
Arrays.stream(claims.get(AUTHORITIES_KEY).toString().split(","))
.map(SimpleGrantedAuthority::new)
.collect(Collectors.toList());
科特林:
val authorities = Arrays.stream(claims[AUTHORITIES_KEY].toString().split(",".toRegex()).dropLastWhile { it.isEmpty() }.toTypedArray())
.map(SimpleGrantedAuthority())
.collect(Collectors.toList<SimpleGrantedAuthority>())
我得到一个类型不匹配错误(Required:
Function<in String!, out (???..???)>!).map(SimpleGrantedAuthority()).如何::new正确地将上述Java代码转换为Kotlin ？
我正在尝试将现有项目升级到Spring 5和Spring Boot 2.0.0.有一个扩展的类,UndertowEmbeddedServletContainerFactory应该在org.springframework.boot.context.embedded.undertow包中.但是,我在当前的Spring Boot 2.0.0.M1/M2/M3/BUILD-SNAPSHOT中看不到这个包或接口.文档似乎仍然引用了这个接口API文档.
这个界面是否被其他东西取代了？
原始代码:
import io.github.jhipster.config.JHipsterConstants;
import io.github.jhipster.config.JHipsterProperties;
import io.github.jhipster.web.filter.CachingHttpHeadersFilter;
import com.codahale.metrics.MetricRegistry;
import com.codahale.metrics.servlet.InstrumentedFilter;
import com.codahale.metrics.servlets.MetricsServlet;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.web.embedded.*;
import org.springframework.boot.web.embedded.undertow.*;//.UndertowEmbeddedServletContainerFactory;
import io.undertow.UndertowOptions;
import org.springframework.boot.web.servlet.ServletContextInitializer;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.core.env.Environment;
import org.springframework.web.cors.CorsConfiguration;
import org.springframework.web.cors.UrlBasedCorsConfigurationSource;
import org.springframework.web.filter.CorsFilter;
import java.io.File;
import java.nio.file.Paths;
import java.util.*;
import javax.servlet.*;
/**
* Configuration of web application with Servlet 3.0 APIs.
*/
@Configuration
public class WebConfigurer implements ServletContextInitializer, EmbeddedServletContainerCustomizer {
private …我已经在Kotlin中覆盖了一个返回一个函数的函数Optional<String>.我如何转换String?和String输入Optional<String>？
例:
override fun getCurrentAuditor(): Optional<String> {
val userName = SecurityUtils.currentUserLogin
return userName ?: SYSTEM_ACCOUNT
}
从上面的例子:
userName 是一个 String?
SYSTEM_ACCOUNT 是一个 String
我在返回语句中遇到错误,两个变量都不是Optional<String>类型.