java-review-structure

强弱类型语言对比及Java特性
本文对比了强类型语言如Java与弱类型语言如Ruby、Python的区别,并介绍了Java的基本数据类型及其特点,探讨了为何基本数据类型不是对象的问题。此外还提到了Unicode编码的应用及其优势。
2008年4月17日 20:50:13
強類型,ruby,python是弱類型
沒有強制類型轉換,Integer j = 1.1; 是錯誤的!
八種基本,八種包裹:wrapped
int-4 short-2 long-8 float-4 double-8 char boolean byte-1
Integer Short Long Float Double Character Boolean Byte
基本數據類型為什么不是對象?是因為降低開銷么?

unicode,前127個跟ascii一樣,有65536個字符
char 16位unicode,2個字節

與平臺無關。增強可移植性。
定義時變量被初始化為適當的“0”


java的全局只能是類,外部的作用域定義了變量,則內部不能夠定義。

java運算一律從左到右。

2008年4月17日 21:04:23
/* Navicat Premium Dump SQL Source Server : EHS_DS Source Server Type : SQL Server Source Server Version : 15004261 (15.00.4261) Source Host : 10.50.52.34:1433 Source Catalog : EHS_DS Source Schema : dbo Target Server Type : SQL Server Target Server Version : 15004261 (15.00.4261) File Encoding : 65001 Date: 05/11/2025 13:42:43 */ -- ---------------------------- -- Table structure for safety_hazard_review_record -- ---------------------------- IF EXISTS (SELECT * FROM sys.all_objects WHERE object_id = OBJECT_ID(N'[dbo].[safety_hazard_review_record]') AND type IN ('U')) DROP TABLE [dbo].[safety_hazard_review_record] GO CREATE TABLE [dbo].[safety_hazard_review_record] ( [id] int IDENTITY(1,1) NOT NULL, [recheck_no] nvarchar(50) COLLATE Chinese_PRC_CI_AS NULL, [oridinal_ref] nvarchar(50) COLLATE Chinese_PRC_CI_AS NULL, [original_source] nvarchar(50) COLLATE Chinese_PRC_CI_AS NULL, [title] nvarchar(255) COLLATE Chinese_PRC_CI_AS NULL, [description] nvarchar(255) COLLATE Chinese_PRC_CI_AS NULL, [urgency_level] nvarchar(50) COLLATE Chinese_PRC_CI_AS NULL, [required_complete_time] datetime NULL, [assignee] nvarchar(50) COLLATE Chinese_PRC_CI_AS NULL, [assigned_time] datetime NULL, [status] nvarchar(50) COLLATE Chinese_PRC_CI_AS NULL, [recheck_result] nvarchar(50) COLLATE Chinese_PRC_CI_AS NULL, [recheck_description] nvarchar(255) COLLATE Chinese_PRC_CI_AS NULL, [actual_complete_time] datetime NULL ) GO ALTER TABLE [dbo].[safety_hazard_review_record] SET (LOCK_ESCALATION = TABLE) GO EXEC sp_addextendedproperty 'MS_Description', N'主键id', 'SCHEMA', N'dbo', 'TABLE', N'safety_hazard_review_record', 'COLUMN', N'id' GO EXEC sp_addextendedproperty 'MS_Description', N'复查单号', 'SCHEMA', N'dbo', 'TABLE', N'safety_hazard_review_record', 'COLUMN', N'recheck_no' GO EXEC sp_addextendedproperty 'MS_Description', N'原始隐患单编号', 'SCHEMA', N'dbo', 'TABLE', N'safety_hazard_review_record', 'COLUMN', N'oridinal_ref' GO EXEC sp_addextendedproperty 'MS_Description', N'原始数据来源', 'SCHEMA', N'dbo', 'TABLE', N'safety_hazard_review_record', 'COLUMN', N'original_source' GO EXEC sp_addextendedproperty 'MS_Description', N'复查标题', 'SCHEMA', N'dbo', 'TABLE', N'safety_hazard_review_record', 'COLUMN', N'title' GO EXEC sp_addextendedproperty 'MS_Description', N'复查描述', 'SCHEMA', N'dbo', 'TABLE', N'safety_hazard_review_record', 'COLUMN', N'description' GO EXEC sp_addextendedproperty 'MS_Description', N'紧急程度 低 中 高', 'SCHEMA', N'dbo', 'TABLE', N'safety_hazard_review_record', 'COLUMN', N'urgency_level' GO EXEC sp_addextendedproperty 'MS_Description', N'要求完成时间', 'SCHEMA', N'dbo', 'TABLE', N'safety_hazard_review_record', 'COLUMN', N'required_complete_time' GO EXEC sp_addextendedproperty 'MS_Description', N'指派人', 'SCHEMA', N'dbo', 'TABLE', N'safety_hazard_review_record', 'COLUMN', N'assignee' GO EXEC sp_addextendedproperty 'MS_Description', N'指派时间', 'SCHEMA', N'dbo', 'TABLE', N'safety_hazard_review_record', 'COLUMN', N'assigned_time' GO EXEC sp_addextendedproperty 'MS_Description', N'状态', 'SCHEMA', N'dbo', 'TABLE', N'safety_hazard_review_record', 'COLUMN', N'status' GO EXEC sp_addextendedproperty 'MS_Description', N'复查结果', 'SCHEMA', N'dbo', 'TABLE', N'safety_hazard_review_record', 'COLUMN', N'recheck_result' GO EXEC sp_addextendedproperty 'MS_Description', N'复查说明', 'SCHEMA', N'dbo', 'TABLE', N'safety_hazard_review_record', 'COLUMN', N'recheck_description' GO EXEC sp_addextendedproperty 'MS_Description', N'实际完成时间', 'SCHEMA', N'dbo', 'TABLE', N'safety_hazard_review_record', 'COLUMN', N'actual_complete_time' GO EXEC sp_addextendedproperty 'MS_Description', N'安全隐患复查记录表', 'SCHEMA', N'dbo', 'TABLE', N'safety_hazard_review_record' GO -- ---------------------------- -- Auto increment value for safety_hazard_review_record -- ---------------------------- DBCC CHECKIDENT ('[dbo].[safety_hazard_review_record]', RESEED, 1) GO -- ---------------------------- -- Primary Key structure for table safety_hazard_review_record -- ---------------------------- ALTER TABLE [dbo].[safety_hazard_review_record] ADD CONSTRAINT [PK__safety_h__3213E83FFF49EEEC] PRIMARY KEY CLUSTERED ([id]) WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY] GO 给我生成一个Java中的实体类
11-06
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