生成代码路径、基本信息及数据库配置
private String packageOutPath = "main.java.com.demo.code.entity";//指定实体生成所在包的路径
private String packagePath = "com.demo.code.entity";//实体类包头
private String authorName = "Zhang Wei";//作者名字
private String tablename = "";//表名
private String[] colnames; // 列名数组
private String[] colTypes; //列名类型数组
private int[] colSizes; //列名大小数组
private boolean f_util = false; // 是否需要导入包java.util.*
private boolean f_sql = false; // 是否需要导入包java.sql.*
//数据库连接
private static final String URL ="jdbc:mysql://localhost:3306/demo?useUnicode=true&characterEncoding=utf-8&useSSL=false";
private static final String NAME = "root";
private static final String PASS = "password";
private static final String DRIVER ="com.mysql.jdbc.Driver";
自动生成实体类完整代码
package com.demo.code;
import java.io.File;
import java.io.FileWriter;
import java.io.IOException;
import java.io.PrintWriter;
import java.sql.Connection;
import java.sql.DatabaseMetaData;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;
/**
* 从数据库表反射出实体类，自动生成实体类
* @author Zhang Wei
*
*/
public class GenEntityMysql {
private String packageOutPath = "main.java.com.demo.code.entity";//指定实体生成所在包的路径
private String packagePath = "com.demo.code.entity";//实体类包头
private String authorName = "Zhang Wei";//作者名字
private String tablename = "";//表名
private String[] colnames; // 列名数组
private String[] colTypes; //列名类型数组
private int[] colSizes; //列名大小数组
private boolean f_util = false; // 是否需要导入包java.util.*
private boolean f_sql = false; // 是否需要导入包java.sql.*
//数据库连接
private static final String URL ="jdbc:mysql://localhost:3306/demo?useUnicode=true&characterEncoding=utf-8&useSSL=false";
private static final String NAME = "root";
private static final String PASS = "password";
private static final String DRIVER ="com.mysql.jdbc.Driver";
/*
* 构造函数
*/
public GenEntityMysql(){
//获取所有的表名
List<String> list=getTableName();
for(int p=0;p<list.size();p++){
tablename = list.get(p);
//创建连接
Connection con;
//查要生成实体类的表
String sql = "select * from " + tablename;
PreparedStatement pStemt = null;
try {
try {
Class.forName(DRIVER);
} catch (ClassNotFoundException e1) {
e1.printStackTrace();
}
con = DriverManager.getConnection(URL,NAME,PASS);
pStemt = con.prepareStatement(sql);
ResultSetMetaData rsmd = pStemt.getMetaData();
int size = rsmd.getColumnCount(); //统计列
colnames = new String[size];
colTypes = new String[size];
colSizes = new int[size];
for (int i = 0; i < size; i++) {
colnames[i] = rsmd.getColumnName(i + 1);
colTypes[i] = rsmd.getColumnTypeName(i + 1);
if(colTypes[i].equalsIgnoreCase("datetime")){
f_util = true;
}
if(colTypes[i].equalsIgnoreCase("image") || colTypes[i].equalsIgnoreCase("text")){
f_sql = true;
}
colSizes[i] = rsmd.getColumnDisplaySize(i + 1);
}
String content = parse(colnames,colTypes,colSizes);
try {
File directory = new File("");
String outputPath = directory.getAbsolutePath()+ "/src/"+this.packageOutPath.replace(".", "/")+"/"+initcap(tablename) + ".java";
FileWriter fw = new FileWriter(outputPath);
PrintWriter pw = new PrintWriter(fw);
pw.println(content);
pw.flush();
pw.close();
} catch (IOException e) {
e.printStackTrace();
}
} catch (SQLException e) {
e.printStackTrace();
} finally{
}
}
System.out.println("生成完毕！");
}
/**
* Java方法 得到当前数据库下所有的表名
*/
private List<String> getTableName() {
List<String> list=new ArrayList<String>();
try {
DatabaseMetaData meta = DriverManager.getConnection(URL,NAME,PASS).getMetaData();
ResultSet rs = meta.getTables(null, null, null,new String[]{"TABLE"});
while (rs.next()) {
list.add(rs.getString(3));
}
}catch(Exception e){
e.printStackTrace();
}
return list;
}
/**
* 功能：生成实体类主体代码
* @param colnames
* @param colTypes
* @param colSizes
* @return
*/
private String parse(String[] colnames, String[] colTypes, int[] colSizes) {
StringBuffer sb = new StringBuffer();
//包路径
sb.append("package " + this.packagePath + ";\r\n");
sb.append("\r\n");
sb.append("import java.io.Serializable;\r\n");
//如果存在时间类型的字段，加入Date引用
if(f_util){
sb.append("import java.util.Date;\r\n\r\n");
}
//引用
sb.append("import javax.persistence.*;\r\n");
sb.append("import lombok.AllArgsConstructor;\r\n");
sb.append("import lombok.Builder;\r\n");
sb.append("import lombok.Data;\r\n");
sb.append("import lombok.NoArgsConstructor;\r\n");
sb.append("import lombok.ToString;\r\n");
//注解
sb.append("@Data\r\n");
sb.append("@Builder\r\n");
sb.append("@NoArgsConstructor\r\n");
sb.append("@AllArgsConstructor\r\n");
sb.append("@ToString\r\n");
sb.append("@Entity\r\n");
sb.append("@Table(name = \"" + tablename + "\" )\r\n");
//实体部分
sb.append("public class " + initcap(tablename) + " implements Serializable {\r\n\r\n");
//序列化
sb.append("\tprivate static final long serialVersionUID = 1L;\r\n\r\n");
processAllAttrs(sb);//属性
sb.append("}\r\n");
// System.out.println(sb.toString());
return sb.toString();
}
/**
* 功能：生成所有属性
* @param sb
*/
private void processAllAttrs(StringBuffer sb) {
for (int i = 0; i < colnames.length; i++) {
//字段下划线分割处理
String rStr = "";
String[] strs = colnames[i].split("_");
if(strs.length > 1){
for (int j = 0; j < strs.length; j++) {
char[] chc = strs[j].toCharArray();
if(j > 0){
if(chc[0] >= 'a' && chc[0] <= 'z'){
chc[0] = (char)(chc[0] - 32);
}
}
rStr += new String(chc);
}
}else{
rStr = colnames[i];
}
//id列单独增加注解标识
if(rStr.equals("id")){
sb.append("\t@Id\r\n\t@GeneratedValue(strategy = GenerationType.IDENTITY)\r\n");
}
//组装属性
sb.append("\tprivate " + sqlType2JavaType(colTypes[i]) + " " + rStr + ";\r\n\r\n");
}
sb.append("\r\n");
}
/**
* 功能：将输入字符串的首字母改成大写
* @param str
* @return
*/
private String initcap(String str) {
char[] ch = str.toCharArray();
if(ch[0] >= 'a' && ch[0] <= 'z'){
ch[0] = (char)(ch[0] - 32);
}
//特殊需要对_进行分割组装
String rStr = "";
String[] strs = str.split("_");
for (int i = 0; i < strs.length; i++) {
char[] chc = strs[i].toCharArray();
if(chc[0] >= 'a' && chc[0] <= 'z'){
chc[0] = (char)(chc[0] - 32);
}
strs[i] = new String(chc);
rStr += strs[i];
}
return new String(rStr);
}
/**
* 功能：获得列的数据类型
* @param sqlType
* @return
*/
private String sqlType2JavaType(String sqlType) {
if(sqlType.equalsIgnoreCase("bit")){
return "boolean";
}else if(sqlType.equalsIgnoreCase("tinyint")){
return "byte";
}else if(sqlType.equalsIgnoreCase("smallint")){
return "short";
}else if(sqlType.equalsIgnoreCase("int")||sqlType.equalsIgnoreCase("INT UNSIGNED")){
//INT UNSIGNED无符号整形
return "Integer";
}else if(sqlType.equalsIgnoreCase("bigint")){
return "long";
}else if(sqlType.equalsIgnoreCase("float")){
return "float";
}else if(sqlType.equalsIgnoreCase("decimal") || sqlType.equalsIgnoreCase("numeric")
|| sqlType.equalsIgnoreCase("real") || sqlType.equalsIgnoreCase("money")
|| sqlType.equalsIgnoreCase("smallmoney")){
return "double";
}else if(sqlType.equalsIgnoreCase("varchar") || sqlType.equalsIgnoreCase("char")
|| sqlType.equalsIgnoreCase("nvarchar") || sqlType.equalsIgnoreCase("nchar")
|| sqlType.equalsIgnoreCase("text")){
return "String";
}else if(sqlType.equalsIgnoreCase("datetime")){
return "Date";
}else if(sqlType.equalsIgnoreCase("image")){
return "Blod";
}
return null;
}
public static void main(String[] args) {
new GenEntityMysql();
}
}
pom.xml依赖包
<!-- MySql -->
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
</dependency>
<!-- lombok -->
<dependency>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
<version>1.16.18</version>
</dependency>
<dependency>
<groupId>org.apache.commons</groupId>
<artifactId>commons-lang3</artifactId>
<version>3.0</version>
</dependency>
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