我试图从Spring-boot开始,在Intellij中使用Maven请帮助我我收到错误:
[ERROR] Failed to execute goal org.apache.maven.plugins:maven-compiler-plugin:3.7.0:compile (default-compile) on project spring-rest: Fatal error compiling: invalid flag: --release -> [Help 1]
[ERROR]
[ERROR] To see the full stack trace of the errors, re-run Maven with the -e switch.
[ERROR] Re-run Maven using the -X switch to enable full debug logging.
[ERROR]
[ERROR] For more information about the errors and possible solutions, please read the following articles:
[ERROR] [Help 1] http://cwiki.apache.org/confluence/display/MAVEN/MojoExecutionException
Process finished with exit code 1
我的pom.xml是:
<?xml version="1.0" encoding="UTF-8"?> <project …使用本机 sql 运算符IN 时，出现异常。虽然它抛出了异常，但它仍然按预期工作，但是日志中的异常有点烦人。我认为这与IN运算符有关。
@Query("select c from Contact c where c.id in :ids")
List<Contact> findByContactsIds(@Param("ids") List<Integer> contactsIds);
配置：
spring.datasource.hikari.max-lifetime=900000
spring.datasource.hikari.leakDetectionThreshold=2000
spring.datasource.hikari.idle-timeout=900000
例外：
2019-02-26 11:25:16.252 WARN 924 --- [l-1 housekeeper] com.zaxxer.hikari.pool.ProxyLeakTask : Connection leak detection triggered for com.mysql.jdbc.JDBC4Connection@ffd3737 on thread http-nio-80-exec-8, stack trace follows
java.lang.Exception: Apparent connection leak detected
at com.zaxxer.hikari.HikariDataSource.getConnection(HikariDataSource.java:128) ~[HikariCP-2.7.9.jar:na]
at org.hibernate.engine.jdbc.connections.internal.DatasourceConnectionProviderImpl.getConnection(DatasourceConnectionProviderImpl.java:122) ~[hibernate-core-5.2.17.Final.jar:5.2.17.Final]
at org.hibernate.internal.NonContextualJdbcConnectionAccess.obtainConnection(NonContextualJdbcConnectionAccess.java:35) ~[hibernate-core-5.2.17.Final.jar:5.2.17.Final]
at org.hibernate.resource.jdbc.internal.LogicalConnectionManagedImpl.acquireConnectionIfNeeded(LogicalConnectionManagedImpl.java:106) ~[hibernate-core-5.2.17.Final.jar:5.2.17.Final]
at org.hibernate.resource.jdbc.internal.LogicalConnectionManagedImpl.getPhysicalConnection(LogicalConnectionManagedImpl.java:136) ~[hibernate-core-5.2.17.Final.jar:5.2.17.Final]
at org.hibernate.resource.jdbc.internal.LogicalConnectionManagedImpl.getConnectionForTransactionManagement(LogicalConnectionManagedImpl.java:254) ~[hibernate-core-5.2.17.Final.jar:5.2.17.Final]
at org.hibernate.resource.jdbc.internal.LogicalConnectionManagedImpl.begin(LogicalConnectionManagedImpl.java:262) ~[hibernate-core-5.2.17.Final.jar:5.2.17.Final]
at org.hibernate.resource.transaction.backend.jdbc.internal.JdbcResourceLocalTransactionCoordinatorImpl$TransactionDriverControlImpl.begin(JdbcResourceLocalTransactionCoordinatorImpl.java:214) ~[hibernate-core-5.2.17.Final.jar:5.2.17.Final]
at org.hibernate.engine.transaction.internal.TransactionImpl.begin(TransactionImpl.java:56) ~[hibernate-core-5.2.17.Final.jar:5.2.17.Final]
at …我有一个java String，它基本上是一个速度模板。
String vt = "#foreach ($number in [1..34]) $number += $number #end"
String result = *String_vt_calculated_by_Velocity_Engine*;
System.out.println(result);
如何在 Java 中计算上述字符串并得到结果？
我正在尝试运行一个JSP项目但是我在构建时遇到了很多错误.
我正在使用 JRE version 1.8.0.112和Tomcat 7,这是错误日志:
Nov 15, 2016 11:15:59 AM org.apache.jasper.compiler.JDTCompiler$1 findType
SEVERE: Compilation error
org.eclipse.jdt.internal.compiler.classfmt.ClassFormatException
at org.eclipse.jdt.internal.compiler.classfmt.ClassFileReader.<init>(ClassFileReader.java:372)
at org.apache.jasper.compiler.JDTCompiler$1.findType(JDTCompiler.java:220)
at org.apache.jasper.compiler.JDTCompiler$1.findType(JDTCompiler.java:176)
at org.eclipse.jdt.internal.compiler.lookup.LookupEnvironment.askForType(LookupEnvironment.java:103)
at org.eclipse.jdt.internal.compiler.lookup.UnresolvedReferenceBinding.resolve(UnresolvedReferenceBinding.java:49)
at org.eclipse.jdt.internal.compiler.lookup.BinaryTypeBinding.resolveType(BinaryTypeBinding.java:122)
at org.eclipse.jdt.internal.compiler.lookup.PackageBinding.getTypeOrPackage(PackageBinding.java:168)
at org.eclipse.jdt.internal.compiler.lookup.Scope.getType(Scope.java:2397)
at org.eclipse.jdt.internal.compiler.ast.TypeDeclaration.resolve(TypeDeclaration.java:1005)
at org.eclipse.jdt.internal.compiler.ast.TypeDeclaration.resolve(TypeDeclaration.java:1235)
at org.eclipse.jdt.internal.compiler.ast.CompilationUnitDeclaration.resolve(CompilationUnitDeclaration.java:540)
at org.eclipse.jdt.internal.compiler.Compiler.process(Compiler.java:759)
at org.eclipse.jdt.internal.compiler.Compiler.compile(Compiler.java:464)
at org.apache.jasper.compiler.JDTCompiler.generateClass(JDTCompiler.java:447)
at org.apache.jasper.compiler.Compiler.compile(Compiler.java:374)
at org.apache.jasper.compiler.Compiler.compile(Compiler.java:352)
at org.apache.jasper.compiler.Compiler.compile(Compiler.java:339)
at org.apache.jasper.JspCompilationContext.compile(JspCompilationContext.java:594)
at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:344)
at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:391)
at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:33
SEVERE: Servlet.service() for servlet jsp threw exception
org.apache.jasper.JasperException: Unable to compile class for JSP:
An error …似乎当我使用自定义序列化程序时，它@JsonInclude(Include.NON_NULL)会被完全忽略。
我的要求是不要序列化值为空的键。我还想通过为多值添加空格分隔符来格式化字符串SortedSet（这就是我创建自定义序列化程序的原因）
没有任何空值的电流输出示例
{
"age": "10",
"fullName": "John Doe"
"email":"doe@john.com john@doe.com test@gmail.com"
}
具有空值的电流输出示例
{
"age": "10",
"fullName": "John Doe"
"email":null
}
电子邮件为空时的预期输出：
{
"age": "10",
"fullName": "John Doe"
}
DTO
@AllArgsConstructor
@Builder
@Data
@NoArgsConstructor
@ToString
@SuppressWarnings("PMD.TooManyFields")
public class User {
@JsonProperty("age")
private String age;
@JsonProperty("firstName")
private String name;
@JsonProperty("email")
@JsonInclude(JsonInclude.Include.NON_EMPTY)
@JsonSerialize(using = MultiValuedCollectionSerializer.class)
private SortedSet<String> email;
}
自定义序列化程序
public class MultiValuedCollectionSerializer extends JsonSerializer<Collection> {
@Override
public void serialize(final Collection inputCollection,
final JsonGenerator jsonGenerator,
final SerializerProvider …