由 Java Entity 类自动生成 SQL建表语句
网上下载的项目，有些只有代码，没有对应的数据库和sql语句。
需要自行根据Entity类来生成建表语句：
1package com.xx;
2
3import java.io.File;
4import java.io.FileOutputStream;
5import java.lang.reflect.Field;
6import java.util.ArrayList;
7import java.util.HashMap;
8import java.util.List;
9import java.util.Map;
10
11import org.slf4j.Logger;
12import org.slf4j.LoggerFactory;
13
14
15/**
16 * 根据 java 类自动生成sql 语句 - mysql
17 */
18public class SqlGenerator {
19 public static Map<String, String> javaProperty2SqlColumnMap = new HashMap<>();
20
21 static {
22 javaProperty2SqlColumnMap.put("Integer", "int");
23 javaProperty2SqlColumnMap.put("Short", "tinyint(4)");
24 javaProperty2SqlColumnMap.put("Long", "bigint");
25 javaProperty2SqlColumnMap.put("BigDecimal", "decimal(19,2)");
26 javaProperty2SqlColumnMap.put("Double", "double precision not null");
27 javaProperty2SqlColumnMap.put("Float", "float");
28 javaProperty2SqlColumnMap.put("boolean", "bit(1)");
29 javaProperty2SqlColumnMap.put("Timestamp", "datetime");
30 javaProperty2SqlColumnMap.put("Date", "datetime");
31 javaProperty2SqlColumnMap.put("String", "varchar(255) CHARACTER SET utf8 COLLATE utf8_general_ci DEFAULT NULL");
32 }
33
34 private static final Logger logger = LoggerFactory.getLogger(SqlGenerator.class);
35
36 public static void main(String[] args) {
37 //实体类所在的package在磁盘上的绝对路径
38 String packageName = "D:\\Documents\\IdeaProjects\\xxxxxxx\\src\\main\\java\\com\\xx\\modules\\cms\\entity";
39 //生成sql的文件夹
40 //String filePath = "D:\\Documents\\IdeaProjects\\xxxxxxx\\";
41 //项目中实体类的路径
42 String prefix = "com.xx.modules.cms.entity.";
43 String className = "";
44
45 StringBuffer sqls = new StringBuffer();
46 //获取包下的所有类名称
47 List<String> list = getAllClasses(packageName);
48 for (String str : list) {
49 className = prefix + str.substring(0, str.lastIndexOf("."));
50 String sql = generateSql(className, "");
51 sqls.append(sql);
52 }
53 System.out.println(sqls.toString());
54 //StringToSql(sqls.toString(), filePath + "report.sql");
55
56 }
57 /**
58 * 根据实体类生成建表语句
59 * @author
60 * @date
61 * @param className 全类名
62 * @param filePath 磁盘路径 如 : d:/workspace/
63 */
64 public static String generateSql(String className, String tableName){
65 try {
66 Class<?> clz = Class.forName(className);
67 className = clz.getSimpleName();
68 Field[] fields = clz.getDeclaredFields();
69 String param = "";
70 String column = "";
71 StringBuilder sql = null;
72 sql = new StringBuilder(50);
73 if (tableName == null || ("").equals(tableName)) {
74 tableName = clz.getName();
75 tableName = tableName.substring(tableName.lastIndexOf(".") + 1);
76 }
77
78 sql.append("\n\n/*========= "+tableName+" ==========*/\n");
79 sql.append("DROP TABLE IF EXISTS `"+className+"`; \n");
80 sql.append("CREATE TABLE `").append(tableName).append("` ( \n");
81
82 String keyField = "";
83 for (Field f : fields) {
84 column = f.getName();
85 if (("serialVersionUID").equals(column)) {
86 continue;
87 }
88 param = f.getType().getSimpleName();
89
90 //将大写字母转小写，并添加下划线
91 for (int i = 0; i < column.length(); i++) {
92 char c = column.charAt(i);
93 if (Character.isUpperCase(c) && i>0) {
94 column = column.replaceAll(
95 Character.toString(c), "_"+Character.toLowerCase(c));
96 }
97 }
98
99 sql.append("`"+ column +"`");
100 sql.append(" ").append(javaProperty2SqlColumnMap.get(param));
101 //默认第一个是主键
102 if ("".equals(keyField)) {
103 keyField = column;
104 }
105 sql.append(",\n");
106 }
107 sql.append("PRIMARY KEY (`"+keyField+"`) USING BTREE,");
108 sql.append("\nINDEX `"+keyField+"`(`"+keyField+"`) USING BTREE ) ");
109 sql.append("\nENGINE = INNODB DEFAULT CHARSET= utf8;");
110
111 return sql.toString();
112
113 } catch (ClassNotFoundException e) {
114 logger.debug("该类未找到！");
115 return null;
116 }
117 }
118
119 /**
120 * 获取包下的所有类名称,获取的结果类似于 XXX.java
121 * @author
122 * @date
123 * @param packageName
124 * @return
125 */
126 public static List<String> getAllClasses(String packageName){
127 List<String> classList = new ArrayList<String>();
128 String className="";
129 File f = new File(packageName);
130 if(f.exists() && f.isDirectory()){
131 File[] files = f.listFiles();
132 for (File file : files) {
133 className = file.getName();
134 classList.add(className);
135 }
136 return classList;
137 }else{
138 logger.debug("包路径未找到！");
139 return null;
140 }
141 }
142 /**
143 * 将string 写入sql文件
144 * @author
145 * @date
146 * @param str
147 * @param path
148 */
149 public static void StringToSql(String str,String path){
150 byte[] sourceByte = str.getBytes();
151 if(null != sourceByte){
152 try {
153 //文件路径（路径+文件名）
154 File file = new File(path);
155 //文件不存在则创建文件，先创建目录
156 if (!file.exists()) {
157 File dir = new File(file.getParent());
158 dir.mkdirs();
159 file.createNewFile();
160 }
161 //文件输出流用于将数据写入文件
162 FileOutputStream outStream = new FileOutputStream(file);
163 outStream.write(sourceByte);
164 outStream.flush();
165 outStream.close();
166 System.out.println("生成成功");
167 } catch (Exception e) {
168 e.printStackTrace();
169 }
170 }
171 }
172}