Java SpringBoot实现带界面的代码生成器详解

server.port=8080
spring.datasource.url=jdbc:mysql://localhost:3306/demo?useUnicode=true&characterEncoding=utf-8&serverTimezone=Asia/Shanghai
spring.datasource.username=root
spring.datasource.password=root

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.5.4</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.yl</groupId>
    <artifactId>generate_code</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>generate_code</name>
    <description>Demo project for Spring Boot</description>
    <properties>
        <java.version>1.8</java.version>
    </properties>
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-freemarker</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <scope>runtime</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>com.google.guava</groupId>
            <artifactId>guava</artifactId>
            <version>30.1-jre</version>
        </dependency>
    </dependencies>
    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>
</project>

package com.yl.generate_code.utils;
import org.springframework.web.servlet.config.annotation.CorsRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurerAdapter;
public class CORFSConfiguration extends WebMvcConfigurerAdapter {
    @Override
    public void addCorsMappings(CorsRegistry registry) {
        //所有请求都允许跨域
        registry.addMapping("/**")
                .allowedOrigins("*")
                .allowedMethods("*")
                .allowedHeaders("*");
    }
}

package com.yl.generate_code.utils;
import com.yl.generate_code.model.Db;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
public class DBUtils {
    private static Connection connection;
    public static Connection getConnection() {
        return connection;
    }
    public static Connection init(Db db) {
        if (connection == null) {
            try {
                Class.forName("com.mysql.cj.jdbc.Driver");
                connection = DriverManager.getConnection( db.getUrl(),db.getUsername(), db.getPassword());
            } catch (ClassNotFoundException e) {
                e.printStackTrace();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
        return connection;
    }
}

package ${packetName}.model;
import java.util.Date;
/**
* @Description: ${modelName}实体类
* @Author: wfj
* @CreateDate ${createDate}
* @Version: 1.0V
*/
public class ${modelName} {
    <#if columns??>
        <#list columns as column>
            <#if column.type='VARCHAR' || column.type='TEXT' || column.type='CHAR'>
                /**
                * ${column.remark}
                */
                private String ${column.propertyName?uncap_first};
            </#if>
            <#if column.type='INT'>
                /**
                * ${column.remark}
                */
                private Integer ${column.propertyName?uncap_first};
            </#if>
            <#if column.type='DATETIME'>
                /**
                * ${column.remark}
                */
                private Date ${column.propertyName?uncap_first};
            </#if>
            <#if column.type='BIGINT'>
                /**
                * ${column.remark}
                */
                private Long ${column.propertyName?uncap_first};
            </#if>
            <#if column.type='DOUBLE'>
                /**
                * ${column.remark}
                */
                private Double ${column.propertyName?uncap_first};
            </#if>
            <#if column.type='BIT'>
                /**
                * ${column.remark}
                */
                private Boolean ${column.propertyName?uncap_first};
            </#if>
        </#list>
        <#list columns as column>
            <#if column.type='VARCHAR' || column.type='TEXT' || column.type='CHAR'>
               public String get${column.propertyName}() {
                    return ${column.propertyName?uncap_first};
                }
                public void set${column.propertyName}(String ${column.propertyName?uncap_first}) {
                    this.${column.propertyName?uncap_first} = ${column.propertyName?uncap_first};
                }
            </#if>
            <#if column.type='INT'>
                public Integer get${column.propertyName}() {
                return ${column.propertyName?uncap_first};
                }
                public void set${column.propertyName}(Integer ${column.propertyName?uncap_first}) {
                this.${column.propertyName?uncap_first} = ${column.propertyName?uncap_first};
                }
            </#if>
            <#if column.type='DATETIME'>
                public Date get${column.propertyName}() {
                return ${column.propertyName?uncap_first};
                }
                public void set${column.propertyName}(Date ${column.propertyName?uncap_first}) {
                this.${column.propertyName?uncap_first} = ${column.propertyName?uncap_first};
                }
            </#if>
            <#if column.type='BIGINT'>
                public Long get${column.propertyName}() {
                return ${column.propertyName?uncap_first};
                }
                public void set${column.propertyName}(Long ${column.propertyName?uncap_first}) {
                this.${column.propertyName?uncap_first} = ${column.propertyName?uncap_first};
                }
            </#if>
            <#if column.type='DOUBLE'>
                public Double get${column.propertyName}() {
                return ${column.propertyName?uncap_first};
                }
                public void set${column.propertyName}(Double ${column.propertyName?uncap_first}) {
                this.${column.propertyName?uncap_first} = ${column.propertyName?uncap_first};
                }
            </#if>
            <#if column.type='BIT'>
                public Boolean get${column.propertyName}() {
                return ${column.propertyName?uncap_first};
                }
                public void set${column.propertyName}(Boolean ${column.propertyName?uncap_first}) {
                this.${column.propertyName?uncap_first} = ${column.propertyName?uncap_first};
                }
            </#if>
        </#list>
    </#if>
}

package com.yl.generate_code.controller;
import com.google.common.base.CaseFormat;
import com.yl.generate_code.model.Db;
import com.yl.generate_code.model.ResultModel;
import com.yl.generate_code.model.TableClass;
import com.yl.generate_code.utils.DBUtils;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RestController;
import java.sql.Connection;
import java.sql.DatabaseMetaData;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;
@RestController
public class DBController {
    @PostMapping("/connect")
    public ResultModel connect(@RequestBody Db db) {
        Connection connection = DBUtils.init(db);
        if (connection == null) {
            return ResultModel.fail("数据库连接失败");
        } else {
            return ResultModel.success("数据库连接成功");
        }
    }
    @PostMapping("/config")
    public ResultModel config(@RequestBody Map<String,Object> map) {
        String packetName = (String)map.get("packetName");
        try {
            //获取数据库连接
            Connection connection = DBUtils.getConnection();
            //获取数据库元数据
            DatabaseMetaData metaData = connection.getMetaData();
            //获取数据库所有的表
            ResultSet rs = metaData.getTables(connection.getCatalog(), null, null, null);
            List<TableClass> list = new ArrayList<>();
            while (rs.next()) {
                TableClass tableClass = new TableClass();
                tableClass.setPacketName(packetName);
                //获取表名
                String tableName = rs.getString("TABLE_NAME");
                //数据库表下划线的字段转成驼峰，且首字母大写
                String modelName = CaseFormat.LOWER_UNDERSCORE.to(CaseFormat.UPPER_CAMEL, tableName);
                tableClass.setTableName(tableName);
                tableClass.setModelName(modelName);
                tableClass.setServiceName(modelName + "Service");
                tableClass.setMapperName(modelName + "Mapper");
                tableClass.setControllerName(modelName + "Controller");
                list.add(tableClass);
            }
            return ResultModel.success("数据库信息读取成功",list);
        } catch (SQLException e) {
            e.printStackTrace();
            return ResultModel.fail("数据库信息读取失败");
        }
    }
}

package com.yl.generate_code.controller;
import com.yl.generate_code.model.ResultModel;
import com.yl.generate_code.model.TableClass;
import com.yl.generate_code.service.GenerateCodeService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.*;
import javax.servlet.http.HttpServletRequest;
import java.util.List;
@RestController
public class GenerateCodeController {
    @Autowired
    private GenerateCodeService generateCodeService;
    @PostMapping("/generateCode")
    public ResultModel generateCode(@RequestBody List<TableClass> list, HttpServletRequest request) {
        return generateCodeService.generateCode(list,request.getServletContext().getRealPath("/"));
    }
}

package com.yl.generate_code.model;
import java.io.Serializable;
public class ColumnClass implements Serializable {
    //实体类属性名
    private String propertyName;
    //实体类属性名对应的表的字段名
    private String columnName;
    //字段类型
    private String type;
    //备注
    private String remark;
    //该字段是否为主键
    private Boolean isPrimary;
    public String getPropertyName() {
        return propertyName;
    }
    public void setPropertyName(String propertyName) {
        this.propertyName = propertyName;
    }
    public String getColumnName() {
        return columnName;
    }
    public void setColumnName(String columnName) {
        this.columnName = columnName;
    }
    public String getType() {
        return type;
    }
    public void setType(String type) {
        this.type = type;
    }
    public String getRemark() {
        return remark;
    }
    public void setRemark(String remark) {
        this.remark = remark;
    }
    public Boolean getPrimary() {
        return isPrimary;
    }
    public void setPrimary(Boolean primary) {
        isPrimary = primary;
    }
    @Override
    public String toString() {
        return "ColumnClass{" +
                "propertyName='" + propertyName + '\'' +
                ", columnName='" + columnName + '\'' +
                ", type='" + type + '\'' +
                ", remark='" + remark + '\'' +
                ", isPrimary=" + isPrimary +
                '}';
    }
}

package com.yl.generate_code.model;
import java.io.Serializable;
public class Db implements Serializable {
    private String username;
    private String password;
    private String url;
    public String getUsername() {
        return username;
    }
    public void setUsername(String username) {
        this.username = username;
    }
    public String getPassword() {
        return password;
    }
    public void setPassword(String password) {
        this.password = password;
    }
    public String getUrl() {
        return url;
    }
    public void setUrl(String url) {
        this.url = url;
    }
}

package com.yl.generate_code.model;
import java.io.Serializable;
public class ResultModel implements Serializable {
    private Integer code;
    private String msg;
    private Object obj;
    public static ResultModel success(String msg,Object obj) {
        return new ResultModel(200,msg,obj);
    }
    public static ResultModel success(String msg) {
        return new ResultModel(200,msg,null);
    }
    public static ResultModel fail(String msg,Object obj) {
        return new ResultModel(500,msg,obj);
    }
    public static ResultModel fail(String msg) {
        return new ResultModel(500,msg,null);
    }
    private ResultModel() {
    }
    public ResultModel(Integer code, String msg, Object obj) {
        this.code = code;
        this.msg = msg;
        this.obj = obj;
    }
    public Integer getCode() {
        return code;
    }
    public void setCode(Integer code) {
        this.code = code;
    }
    public String getMsg() {
        return msg;
    }
    public void setMsg(String msg) {
        this.msg = msg;
    }
    public Object getObj() {
        return obj;
    }
    public void setObj(Object obj) {
        this.obj = obj;
    }
}

package com.yl.generate_code.model;
import java.io.Serializable;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;
public class TableClass implements Serializable {
    private String tableName;
    private String modelName;
    private String serviceName;
    private String mapperName;
    private String controllerName;
    private String packetName;
    private String createDate;
    private List<ColumnClass> columns = new ArrayList<>();
    public String getTableName() {
        return tableName;
    }
    public void setTableName(String tableName) {
        this.tableName = tableName;
    }
    public String getModelName() {
        return modelName;
    }
    public void setModelName(String modelName) {
        this.modelName = modelName;
    }
    public String getServiceName() {
        return serviceName;
    }
    public void setServiceName(String serviceName) {
        this.serviceName = serviceName;
    }
    public String getMapperName() {
        return mapperName;
    }
    public void setMapperName(String mapperName) {
        this.mapperName = mapperName;
    }
    public String getControllerName() {
        return controllerName;
    }
    public void setControllerName(String controllerName) {
        this.controllerName = controllerName;
    }
    public String getPacketName() {
        return packetName;
    }
    public void setPacketName(String packetName) {
        this.packetName = packetName;
    }
    public List<ColumnClass> getColumns() {
        return columns;
    }
    public void setColumns(List<ColumnClass> columns) {
        this.columns = columns;
    }
    public String getCreateDate() {
        return createDate;
    }
    public void setCreateDate(String createDate) {
        this.createDate = createDate;
    }
}

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <!--引入vue.js,elementui和axios-->
    <script src="https://cdn.jsdelivr.net/npm/vue@2/dist/vue.js"></script>
    <!-- 引入样式 -->
    <link rel="stylesheet" href="https://unpkg.com/element-ui/lib/theme-chalk/index.css">
    <!-- 引入组件库 -->
    <script src="https://unpkg.com/element-ui/lib/index.js"></script>
    <script src="https://unpkg.com/axios/dist/axios.min.js"></script>
</head>
<body>
<div id="app">
    <table>
        <tr>
            <td><el-tag size="mini">数据库用户名:</el-tag></td>
            <td><el-input size="mini" v-model="db.username"></el-input></td>
        </tr>
        <tr>
            <td><el-tag size="mini">数据库密码:</el-tag></td>
            <td><el-input size="mini" v-model="db.password"></el-input></td>
        </tr>
        <tr>
            <td><el-tag size="mini">数据库连接地址:</el-tag></td>
            <td><el-input size="mini" v-model="db.url">
                <template slot="prepend">jdbc:mysql://</template>
                <template slot="append">?useUnicode=true&characterEncoding=utf-8&serverTimezone=Asia/Shanghai</template>
            </el-input></td>
        </tr>
    </table>
    <div style="display: flex">
        <el-button type="primary" size="mini" @click="connect" :disabled="!enableButton">连接数据库</el-button>
        <div style="color: red;font-weight: bold" >{{msg}}</div>
        <el-input v-model="packetName" size="mini" style="width:300px"></el-input>
        <el-button size="mini" type="primary" @click="config">配置</el-button>
    </div>
    <el-table
            :data="tableData"
            stripe
            border
            style="width: 100%">
        <el-table-column
                prop="tableName"
                label="表名称"
                width="180">
        </el-table-column>
        <el-table-column
                label="实体类名称"
                width="180">
            <template slot-scope="scope">
                <el-input v-model="scope.row.modelName"></el-input>
            </template>
        </el-table-column>
        <el-table-column
                label="mapper名称">
            <template slot-scope="scope">
                <el-input v-model="scope.row.mapperName"></el-input>
            </template>
        </el-table-column>
        <el-table-column
                label="service名称">
            <template slot-scope="scope">
                <el-input v-model="scope.row.serviceName"></el-input>
            </template>
        </el-table-column>
        <el-table-column
                label="controller名称">
            <template slot-scope="scope">
                <el-input v-model="scope.row.controllerName"></el-input>
            </template>
        </el-table-column>
    </el-table>
    <div>
        <el-button type="success" size="mini" @click="generateCode">生成代码</el-button>
        <div style="color: green;font-weight: bold">{{result}}</div>
        <div>{{codePath}}</div>
    </div>
</div>
<script>
    new Vue({
        el:"#app",
        data() {
            return{
                result: '',
                codePath: '',
                tableData:[],
                packetName: 'com.yl',
                msg : "数据库未连接",
                enableButton: true,
                db: {
                    username: "root",
                    password: "root",
                    url : "localhost:3306/demo"
                }
            }
        },
        methods: {
            connect() {
                let _this = this
                this.db.url = "jdbc:mysql://" + this.db.url + "?useUnicode=true&characterEncoding=utf-8&serverTimezone=Asia/Shanghai"
                axios.post("/connect",this.db).then(res => {
                    console.log(res.data)
                    _this.db = {
                        username: "root",
                        password: "root",
                        url : "localhost:3306/demo"
                    }
                    _this.msg = res.data.msg
                    _this.enableButton = false
                }).catch(err => {
                    console.log(err)
                })
            },
            config() {
                let _this = this
                axios.post("/config",{packetName: _this.packetName}).then(res => {
                    console.log(res.data)
                    _this.msg = res.data.msg
                    _this.tableData = res.data.obj
                }).catch(err => {
                    console.log(err)
                })
            },
            generateCode() {
                let _this = this
                axios.post("/generateCode",_this.tableData).then(res => {
                    console.log(res.data)
                    _this.result = res.data.msg
                    _this.codePath = res.data.obj
                }).catch(err => {
                    console.log(err)
                })
            }
        }
    })
</script>
</body>
</html>

package com.yl.generate_code.service;
import com.yl.generate_code.model.ResultModel;
import com.yl.generate_code.model.TableClass;
import javax.servlet.http.HttpServletRequest;
import java.util.List;
public interface GenerateCodeService {
    ResultModel generateCode(List<TableClass> list, String realpath);
}

package com.yl.generate_code.service.impl;
import com.google.common.base.CaseFormat;
import com.yl.generate_code.model.ColumnClass;
import com.yl.generate_code.model.ResultModel;
import com.yl.generate_code.model.TableClass;
import com.yl.generate_code.service.GenerateCodeService;
import com.yl.generate_code.utils.DBUtils;
import freemarker.cache.ClassTemplateLoader;
import freemarker.template.Configuration;
import freemarker.template.Template;
import freemarker.template.TemplateException;
import org.springframework.stereotype.Service;
import javax.servlet.http.HttpServletRequest;
import java.io.*;
import java.sql.Connection;
import java.sql.DatabaseMetaData;
import java.sql.ResultSet;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;
@Service
public class GenerateCodeServiceImpl implements GenerateCodeService {
    Configuration cfg = null;
    {
        cfg = new Configuration(Configuration.VERSION_2_3_31);
        cfg.setTemplateLoader(new ClassTemplateLoader(GenerateCodeServiceImpl.class,"/templates"));
        cfg.setDefaultEncoding("utf-8");
    }
    @Override
    public ResultModel generateCode(List<TableClass> list, String realpath) {
        try {
            Template modelTemplate = cfg.getTemplate("Model.java.ftl");
            Template serviceTemplate = cfg.getTemplate("Service.java.ftl");
            Template serviceImplTemplate = cfg.getTemplate("ServiceImpl.java.ftl");
            Template mapperTemplate = cfg.getTemplate("Mapper.java.ftl");
            Template mapperXmlTemplate = cfg.getTemplate("Mapper.xml.java.ftl");
            Template controllerTemplate = cfg.getTemplate("Controller.java.ftl");
            Connection connection = DBUtils.getConnection();
            DatabaseMetaData metaData = connection.getMetaData();
            for (TableClass tableClass : list) {
                //根据表名获取该表的所有字段
                ResultSet columns = metaData.getColumns(connection.getCatalog(), null, tableClass.getTableName(), null);
                //获取该表的所有主键
                ResultSet primaryKeys = metaData.getPrimaryKeys(connection.getCatalog(), null, tableClass.getTableName());
                List<ColumnClass> columnClasses = new ArrayList<>();
                while (columns.next()) {
                    //获取字段名
                    String column_name = columns.getString("COLUMN_NAME");
                    //获取字段类型
                    String type_name = columns.getString("TYPE_NAME");
                    //获取字段注释
                    String remark = columns.getString("REMARKS");
                    ColumnClass columnClass = new ColumnClass();
                    columnClass.setColumnName(column_name);
                    columnClass.setType(type_name);
                    columnClass.setRemark(remark);
                    columnClass.setPropertyName(CaseFormat.LOWER_UNDERSCORE.to(CaseFormat.UPPER_CAMEL,column_name));
                    //指标挪到第一
                    primaryKeys.first();
                    while (primaryKeys.next()) {
                        String primaryKey = primaryKeys.getString("COLUMN_NAME");
                        if (column_name.equals(primaryKey)) {
                            columnClass.setPrimary(true);
                        }
                    }
                    columnClasses.add(columnClass);
                }
                tableClass.setColumns(columnClasses);
                SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
                tableClass.setCreateDate(sdf.format(new Date()));
                String path = realpath + "/" + tableClass.getPacketName().replace(".","/");
                generate(modelTemplate,tableClass,path+"/model/",1);
                generate(serviceTemplate,tableClass,path+"/service/",1);
                generate(serviceImplTemplate,tableClass,path+"/service/impl",1);
                generate(mapperTemplate,tableClass,path+"/mapper/",1);
                generate(mapperXmlTemplate,tableClass,path+"/mapper/",2);
                generate(controllerTemplate,tableClass,path+"/controller/",1);
            }
            return ResultModel.success("代码已生成",realpath);
        } catch (Exception e) {
            e.printStackTrace();
            return ResultModel.fail("代码生成失败");
        }
    }
    private void generate(Template template,TableClass tableClass,String path,Integer flag) throws IOException, TemplateException {
        File file = new File(path);
        if (!file.exists()) {
            file.mkdirs();
        }
        String fileName;
        if (flag == 1) {
            fileName = path + "/" + tableClass.getModelName() + template.getName().replace(".ftl","").replace("Model","");
        } else {
            fileName = path + "/" + tableClass.getModelName() + template.getName().replace(".ftl","").replace(".java","");
        }
        FileOutputStream fos = new FileOutputStream(fileName);
        OutputStreamWriter  out = new OutputStreamWriter(fos);
        template.process(tableClass,out);
        fos.close();
        out.close();
    }
}