Null pointer problem in batch operations such as saveBatch in mybatis-plus describe: Error message Solutions solution doubt Reference blog Description: It’s almost time to get off work again, haha. I hope I can help you. I’ll explain it in a scribble. Null pointers will appear in batch operations, but there is no problem in a […]
Tag: null
ResolvedFailed to start bean documentationPluginsBootstrapper; nested exception .lang.NullPointerEx
Article directory Exception information reason Solution Plan 0 plan 1 Insert image description here Exception information Failed to start bean ‘documentationPluginsBootstrapper’; nested exception is java.lang.NullPointerException 2023-11-10 11:21:44.013 ERROR 44100 — [o-8080-Acceptor] org.apache.tomcat.util.net.Acceptor : Socket accept failed java.nio.channels.AsynchronousCloseException: null at java.base/java.nio.channels.spi.AbstractInterruptibleChannel.end(AbstractInterruptibleChannel.java:202) ~[na:na] at java.base/sun.nio.ch.ServerSocketChannelImpl.end(ServerSocketChannelImpl.java:269) ~[na:na] at java.base/sun.nio.ch.ServerSocketChannelImpl.accept(ServerSocketChannelImpl.java:288) ~[na:na] at org.apache.tomcat.util.net.NioEndpoint.serverSocketAccept(NioEndpoint.java:547) ~[tomcat-embed-core-9.0.68.jar:9.0.68] at org.apache.tomcat.util.net.NioEndpoint.serverSocketAccept(NioEndpoint.java:79) ~[tomcat-embed-core-9.0.68.jar:9.0.68] at org.apache.tomcat.util.net.Acceptor.run(Acceptor.java:129) […]
Easypoi map method imports data, List＜Map＜String, String＞＞ Date item data is empty (null) solution
Directory Preface Solution Foreword When using easypoi map to parse an excel file, if the data format of a certain column in the file is date type, then this tool cannot read it, because its source code reads a certain column in date format, and the data must be a string type, it will handle […]
Error: ERROR Cannot read properties of null (reading type)
ERROR Cannot read properties of null (reading type’) TypeError: Cannot read properties of null (reading type’) <template> <el-card> <el-row :gutter=”20″ class=”header”> <el-col :span=”7″> <el-input placeholder=”Please enter the product category name…” v-model=”queryForm.query” clearable></el-input> </el-col> <el-button type=”primary” :icon=”Search” @click=”initBigTypeList”>Search</el-button> <el-button type=”primary” :icon=”DocumentAdd” @click=”handleDialogValue()”>Add product category</el-button> </el-row> <el-table :data=”tableData” stripe style=”width: 100%”> <el-table-column prop=”id” label=”#ID” width=”80″ /> <el-table-column […]
Collectors.toMap error: null pointer & duplicate key
The stream in Java 8 has been widely used by students in project development. Of course, everyone has also stepped on many pitfalls. Next, I will talk about the pitfalls of Collections.toMap in project use, so as to avoid being pitted again. 1. Introduction to Collectors.toMap Collectors.toMap is a collector in Java 8 that can […]
When the java backend returns data to the front end, attributes with empty or NULL values are removed and certain attributes are ignored.
Table of Contents 1. Usage scenarios 2. Environmental preparation 1. Introduce dependencies 2. Entity class 3. Example 1. Do not return null value (1)Method (2)Test (3)Explanation 2. Do not return some attributes (1)Method (2)Test 4. Jackson common annotations 1. @JsonProperty 2. @JsonPropertyOrder 3. @JsonInclude 4. @JsonIgnoreProperties 5. @JsonFormat 6. @JsonUnwrapped 1. Usage scenarios During the […]
2023/10/26–C#–Null, double question mark? ? , immutable array, multidimensional array, traversal array
1.Null // Features: //1. Indicates a null reference that does not refer to any object, no memory space is created, and a null reference pointer is stored; //2.Null type is System.Nullable the type of this struct //3. For value types, the assignment cannot be directly null, but the reference type can //4.Default value of null […]
Major online incident! Null pointer problem caused by ternary expression
It’s really exciting. I encountered this kind of epic online bug not long after I joined the company. The homepage crashed directly and the old code exploded. No matter what the underlying reason is, I feel that the main reason is that the upstream and downstream links are too complicated. , management is relatively difficult, […]
C++ Standard Templates (STL) – Type Support (type attributes, is_void, is_null_pointer, is_integral)
Type attributes A type attribute defines a compile-time template-based structure for querying or modifying the properties of a type. Attempting to specialize a template defined in the header causes undefined behavior, except that std::common_type can be specialized as described. Templates defined in the header file may be instantiated with incomplete types unless otherwise specified, although […]
[C++] Inline functions, auto keyword, range-based for loop, pointer null value nullptr
Fan Zimu: Personal homepage Personal columns: “C Language” “Data Structure” “Lanqiao Cup Test Questions” “LeetCode Question Notes” “Practical Training Projects” “C++” Every day without dancing is a betrayal of life Table of Contents Preface 1. Inline functions 1.1 Concept 1.2 Features 2.auto keyword 2.1 Thinking about type aliases 2.2Introduction to auto 2.3Usage details of auto […]