前面寫了生成表的實體類的MySQL數據庫版，這裏再貼上PostgreSQL數據庫版。
注：pgsql字段類型所對應的Java類型只寫了常見的部分類型，如有需要請自行修改完善sqlType2JavaType方法。
package generator;
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.sql.Statement;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Date;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
/**
* 從數據庫生成表的實體類
* PostgreSQL版
*/
public class PgSQlGenerateEntityUtil {
public static void main(String[] args) {
PgSQlGenerateEntityUtil pgGen = new PgSQlGenerateEntityUtil();
//PgSQlGenerateEntityUtil.basePath=""; //指定生成的位置,默認是當前工程
//pgGen.needEntityHelper=true;
//生成的包名
PgSQlGenerateEntityUtil.packageOutPath = "net.hlinfo.entity";
pgGen.generate();
System.out.println("generate Entity to classes successful!");
}
//表名
private String tableName;
//表註釋
private String tableComment;
//列名數組
private String[] colNames;
//列名類型數組
private String[] colTypes;
//列名大小數組
private int[] colSizes;
//列名註釋
private Map colNamesComment = new HashMap();
//是否需要導入包java.util.*
private boolean needUtil = false;
//是否需要導入包java.sql.*
private boolean needSql = false;
//是否需要導入包java.math.BigDecimal
private boolean needBigDecimal = false;
//是否創建EntityHelper
private boolean needEntityHelper = false;
private static final SimpleDateFormat SDF = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
// 數據庫配置信息
private static final String JDBC_URL = "jdbc:postgresql://127.0.0.1:5432/test";
public static final String jdbc_user = "postgres";
public static final String jdbc_pwd = "123456";
private static final String DRIVER = "org.postgresql.Driver";
//指定實體生成所在包的路徑
private static String basePath = new File("").getAbsolutePath();
//指定包名
private static String packageOutPath = "com.cy.entity";
//作者名字
private static final String authorName = "吶喊";
//指定需要生成的表的表名，全部生成設置爲null
private String[] generateTables = null;
//主鍵
private static String pk;
private PgSQlGenerateEntityUtil() {
}
/**
* 功能：查詢表信息的sql
* @param tableName
* @return comment 表的註釋，type字段類型，name字段名字，notnull是否爲空
*/
private static String SQL(String tableName) {
if(tableName==null || "".equals(tableName)) {return null;}
String sql = "SELECT col_description(a.attrelid,a.attnum) as comment,"
+ "format_type(a.atttypid,a.atttypmod) as type,a.attname as name, a.attnotnull as notnull,a.atttypmod-4 as fields_length "
+ "FROM pg_class as c,pg_attribute as a where c.relname = '"+tableName+"' "
+ "and a.attrelid = c.oid and a.attnum>0";
return sql;
}
/**
* 功能：獲取主鍵的sql
* @param tableName
* @return pk_name:主鍵名 | colname：主鍵對應字段名 | typename:主鍵類型
*/
private static String PK_SQL(String tableName) {
if(tableName==null || "".equals(tableName)) {return null;}
String pksql = "select pg_constraint.conname as pk_name,pg_attribute.attname as colname,pg_type.typname as typename from pg_constraint inner join pg_class on pg_constraint.conrelid = pg_class.oid inner join pg_attribute on pg_attribute.attrelid = pg_class.oid and pg_attribute.attnum = pg_constraint.conkey[1] inner join pg_type on pg_type.oid = pg_attribute.atttypid where pg_class.relname = '"+tableName+"' and pg_constraint.contype='p'";
return pksql;
}
/**
* 功能：解析字段數據，生成實體類的所有內容
* @return
*/
private String parse() {
StringBuffer sb = new StringBuffer();
sb.append("package " + packageOutPath + ";\r\n");
sb.append("\r\n");
// 判斷是否導入工具包
if (needUtil) {
sb.append("import java.util.Date;\r\n");
}
if (needSql) {
sb.append("import java.sql.*;\r\n");
}
for (int i = 0; i < colNames.length; i++) {
String hasbd = sqlType2JavaType(colTypes[i]);
if(hasbd =="BigDecimal" || "BigDecimal".equals(hasbd)) {needBigDecimal=true;}
}
if(needBigDecimal) {
sb.append("import java.math.BigDecimal;\r\n");
}
// 註釋部分
sb.append("/**\r\n");
sb.append(" * <ul>\r\n");
sb.append(" * <li>table name: " + tableName + "</li>\r\n");
sb.append(" * <li>table comment: " + (tableComment==null?"":tableComment) + "</li>\r\n");
sb.append(" * <li>author name: " + authorName + "</li>\r\n");
sb.append(" * <li>create time: " + SDF.format(new Date()) + "</li>\r\n");
sb.append(" * </ul>\r\n");
sb.append(" */ \r\n");
// 實體部分
String classExtends = "";
if(needEntityHelper) {
classExtends=" extends EntityHelper";
}
sb.append("public class " + under2camel(tableName, true) + classExtends + "{\r\n\r\n");
//實體屬性
processAllAttrs(sb);
sb.append("\r\n");
// 構造函數
processConstructor(sb);//
//get set方法
processAllMethod(sb);
processToString(sb);
if(needEntityHelper) {
processEntityHelper(sb,pk);
}
sb.append("}\r\n");
return sb.toString();
}
/**
* @param sb
* @description 生成所有成員變量及註釋
*/
private void processAllAttrs(StringBuffer sb) {
for (int i = 0; i < colNames.length; i++) {
if(colNamesComment.get(colNames[i])!=null &&!"".equals(colNamesComment.get(colNames[i]))) {
sb.append("\t/*"+colNamesComment.get(colNames[i])+"*/\r\n");
}
sb.append("\tprivate " + sqlType2JavaType(colTypes[i]) + " " + colNames[i] + ";\r\n");
}
}
/**
* EntityHelper
* @param sb
* @param pk
*/
private void processEntityHelper(StringBuffer sb,String pk) {
sb.append("\t@Override\r\n");
sb.append("\tpublic String getPrimaryKey() {\r\n");
sb.append("\t\treturn \""+pk+"\";\r\n");
sb.append("\t}\r\n");
}
/**
* 重寫toString()方法
* @param sb
*/
private void processToString(StringBuffer sb) {
sb.append("\t@Override\r\n\tpublic String toString() {\r\n");
sb.append("\t\treturn \"" +tableName + "[\" + \r\n");
for (int i = 0; i < colNames.length; i++) {
if (i != 0)
sb.append("\t\t\t\", ");
if (i == 0)
sb.append("\t\t\t\"");
sb.append(colNames[i] + "=\" + "
+ colNames[i]).append(" + \r\n");
if (i == colNames.length - 1) {
sb.append("\t\t\t\"]\";\r\n");
}
}
sb.append("\t}\r\n");
}
/**
* 構造函數
* @param sb
*/
private void processConstructor(StringBuffer sb) {
StringBuffer p = new StringBuffer();
StringBuffer v = new StringBuffer();
for(int i = 0; i < colNames.length; i++) {
p.append(sqlType2JavaType(colTypes[i])+" "+colNames[i]);
if(i!=colNames.length-1) {
p.append(",");
}
v.append("\t\tthis."+colNames[i]+"="+colNames[i]+";\r\n");
}
//無參數構造函數
sb.append("\tpublic "+under2camel(tableName,true)+"() {\r\n");
sb.append("\t\tsuper();\r\n");
sb.append("\t}\r\n");
//帶參構造函數
sb.append("\tpublic "+under2camel(tableName,true)+"("+p.toString()+") {\r\n");
sb.append(v.toString());
sb.append("\t}\r\n");
}
/**
* @param sb
* @description 生成所有get/set方法
*/
private void processAllMethod(StringBuffer sb) {
for (int i = 0; i < colNames.length; i++) {
sb.append("\tpublic void set" + initCap(colNames[i]) + "(" + sqlType2JavaType(colTypes[i]) + " "
+ colNames[i] + "){\r\n");
sb.append("\t\tthis." + colNames[i] + "=" + colNames[i] + ";\r\n");
sb.append("\t}\r\n");
sb.append("\tpublic " + sqlType2JavaType(colTypes[i]) + " get" + initCap(colNames[i]) + "(){\r\n");
sb.append("\t\treturn " + colNames[i] + ";\r\n");
sb.append("\t}\r\n");
}
}
/**
* 功能：將傳入字符串的首字母轉成大寫
* @param str 傳入字符串
* @return
*/
private String initCap(String str) {
char[] ch = str.toCharArray();
if (ch[0] >= 'a' && ch[0] <= 'z')
ch[0] = (char) (ch[0] - 32);
return new String(ch);
}
/**
* 功能：下劃線命名轉駝峯命名
* @param s
* @param fistCharToUpperCase 首字母是否大寫
* @author 吶喊
* @return
*/
private String under2camel(String s,boolean fistCharToUpperCase) {
String separator = "_";
String under="";
s = s.toLowerCase().replace(separator, " ");
String sarr[]=s.split(" ");
for(int i=0;i<sarr.length;i++)
{
String w=sarr[i].substring(0,1).toUpperCase()+sarr[i].substring(1);
under +=w;
}
if(!fistCharToUpperCase) {
under = under.substring(0,1).toLowerCase()+under.substring(1);
}
return under;
}
/**
* 功能：查找pgsql字段類型所對應的Java類型
* @return
*/
private String sqlType2JavaType(String sqlType) {
if(sqlType.indexOf("(")>0) {
sqlType = sqlType.substring(0, sqlType.indexOf("("));
}
String returnType=null;
switch (sqlType) {
case "boolean":
case "bit":
returnType = "boolean";
break;
case "bytea":
returnType = "byte";
break;
case "bigint":
case "int8":
case "bigserial":
returnType = "Long";
break;
case "integer":
case "int2":
case "int4":
case "smallint":
case "serial":
returnType = "Integer";
break;
case "real":
case "double precision":
returnType = "double";
break;
case "text":
case "character varying":
case "character":
case "varchar":
case "char":
case "uuid":
case "json":
case "xml":
case "money":
case "timestamp without time zone":
case "timestamp with time zone":
case "time without time zone":
case "time with time zone":
returnType = "String";
break;
case "inet":
case "cidr":
case "macaddr":
case "macaddr8":
case "box":
case "circle":
case "interval":
case "line":
case "lseg":
case "path":
case "point":
case "polygon":
case "varbit":
returnType = "Object";
break;
case "numeric":
case "decimal":
returnType = "BigDecimal";
break;
default:
break;
}
return returnType;
}
/**
* 功能：獲取並創建實體所在的路徑目錄
* @return
*/
private static String pkgDirName() {
String dirName = basePath + "/src/" + packageOutPath.replace(".", "/");
File dir = new File(dirName);
if (!dir.exists()) {dir.mkdirs();System.out.println("mkdirs dir 【" + dirName + "】");}
return dirName;
}
/**
* 功能：生成EntityHelper
*/
private void EntityHelper() {
String dirName = PgSQlGenerateEntityUtil.pkgDirName();
String javaPath = dirName + "/EntityHelper.java";
try {
StringBuffer sb = new StringBuffer();
sb.append("package " + packageOutPath + ";\r\n");
sb.append("\r\n");
sb.append("public abstract class EntityHelper{\r\n\r\n");
sb.append("\tpublic abstract String getPrimaryKey();\r\n");
sb.append("\r\n");
sb.append("}\r\n");
FileWriter fw = new FileWriter(javaPath);
PrintWriter pw = new PrintWriter(fw);
pw.println(sb.toString());
pw.flush();
if (pw != null){pw.close();}
System.out.println("create class 【EntityHelper】");
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
/**
* 功能： 生成實體類的主方法
*/
private void generate(){
Connection conn=null;
try {
//數據庫的連接
PreparedStatement pStemt = null;
Class.forName(DRIVER);
conn = DriverManager.getConnection(JDBC_URL, jdbc_user, jdbc_pwd);
if(conn!=null) {
System.out.println("connect database success..."+conn);
}else {
System.out.println("connect database failed^_^");
return;
}
//獲取數據庫的元數據
DatabaseMetaData db = conn.getMetaData();
//是否有指定生成表，有指定則直接用指定表，沒有則全表生成
List<String> tableNames = new ArrayList<>();
List<String> tableComments = new ArrayList<>();
if (generateTables == null) {
//從元數據中獲取到所有的表名
ResultSet rs = db.getTables(null, null, null, new String[] { "TABLE" });
while (rs.next()) {
tableNames.add(rs.getString(3));//表名
tableComments.add(rs.getString(5));//表註釋
}
} else {
for (String tableName : generateTables) tableNames.add(tableName);
}
if(needEntityHelper) {
EntityHelper();
}
String tableSql;
PrintWriter out = null;
for (int j = 0; j < tableNames.size(); j++) {
tableName = tableNames.get(j);
tableComment = tableComments.get(j);
tableSql = SQL(tableName);
pStemt = conn.prepareStatement(tableSql,ResultSet.TYPE_SCROLL_INSENSITIVE,ResultSet.CONCUR_READ_ONLY);
ResultSet rstb = pStemt.executeQuery();
rstb.last();
int rowCount = rstb.getRow();
rstb.beforeFirst();
colNames = new String[rowCount];
colTypes = new String[rowCount];
colSizes = new int[rowCount];
int idx = 0;
while(rstb.next()) {
colNames[idx] = rstb.getString("name");
colTypes[idx] = rstb.getString("type");
colSizes[idx] = rstb.getInt("fields_length");
colNamesComment.put(rstb.getString("name"), rstb.getString("comment"));
idx++;
}
//獲取主鍵
pStemt = conn.prepareStatement(PK_SQL(tableName));
ResultSet rspk = pStemt.executeQuery();
while(rspk.next()) {
pk=rspk.getString("colname");
}
//解析生成實體java文件的所有內容
String content = parse();
//輸出生成文件
String dirName = PgSQlGenerateEntityUtil.pkgDirName();
String javaPath = dirName + "/" + under2camel(tableName, true) + ".java";
FileWriter fw = new FileWriter(javaPath);
out = new PrintWriter(fw);
out.println(content);
out.flush();
System.out.println("create class 【" + tableName + "】");
}
if (out != null) {
out.close();
}
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}finally {
if(conn!=null) {
try {
conn.close();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
}
}