22.SSM整合

一、整合流程

1. 创建工程
2. SSM整合

• Spring
  • SpringConfig
• MyBatis
  • MybatisConfig
  • JdbcConfig
  • jdbc.properties
• SpringMVC
  • ServletConfig
  • SpringMvcConfig

二、快速构建

1. 导入坐标,引入tomcat

    <dependencies>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-webmvc</artifactId>
            <version>5.3.19</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-jdbc</artifactId>
            <version>5.3.18</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-test</artifactId>
            <version>5.3.18</version>
        </dependency>
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis</artifactId>
            <version>3.5.5</version>
        </dependency>
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis-spring</artifactId>
            <version>2.0.6</version>
        </dependency>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.32</version>
        </dependency>
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid</artifactId>
            <version>1.1.12</version>
        </dependency>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.13</version>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>javax.servlet-api</artifactId>
            <version>3.0.1</version>
            <scope>provided</scope>
        </dependency>
        <!--json转换-->
        <dependency>
            <groupId>com.fasterxml.jackson.core</groupId>
            <artifactId>jackson-databind</artifactId>
            <version>2.9.0</version>
        </dependency>
    </dependencies>
    <!--tomcat插件-->
    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.tomcat.maven</groupId>
                <artifactId>tomcat7-maven-plugin</artifactId>
                <version>2.2</version>
                <configuration>
                    <port>80</port>
                    <path>/</path>
                </configuration>
            </plugin>
        </plugins>
    </build>

2. 创建配置文件

• 结构图

  
  image.png
• SpringConfig

package com.ylf.config;

import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Import;
import org.springframework.context.annotation.PropertySource;

@Configuration
@ComponentScan({"com.ylf.service"})
@PropertySource("jdbc.properties")
@Import({JdbcConfig.class, MyBatisConfig.class})
// 开启事务注解
@EnableTransactionManagement
public class SpringConfig {
}

• JdbcConfig

package com.ylf.config;

import com.alibaba.druid.pool.DruidDataSource;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Bean;

import javax.sql.DataSource;

public class JdbcConfig {
  @Value("${jdbc.driver}")
  private String driver;
  @Value("${jdbc.url}")
  private String url;
  @Value("${jdbc.name}")
  private String name;
  @Value("${jdbc.password}")
  private String password;

  @Bean
  public DataSource dataSource(){
    final DruidDataSource dataSource = new DruidDataSource();
    dataSource.setDriverClassName(driver);
    dataSource.setUrl(url);
    dataSource.setUsername(name);
    dataSource.setPassword(password);
    return dataSource;
  }
}

  @Bean
  public PlatformTransactionManager transactionManager(DataSource dataSource) {
    DataSourceTransactionManager ds = new DataSourceTransactionManager();
    ds.setDataSource(dataSource);
    return ds;
  }

• MyBatisConfig

package com.ylf.config;

import org.mybatis.spring.SqlSessionFactoryBean;
import org.mybatis.spring.mapper.MapperScannerConfigurer;
import org.springframework.context.annotation.Bean;

import javax.sql.DataSource;

public class MyBatisConfig {
  @Bean
  public SqlSessionFactoryBean sqlSessionFactory(DataSource dataSource) {
    SqlSessionFactoryBean factoryBean = new SqlSessionFactoryBean();
    factoryBean.setDataSource(dataSource);
    factoryBean.setTypeAliasesPackage("com.ylf.pojo");
    return factoryBean;
  }

  @Bean
  public MapperScannerConfigurer mapperScannerConfigurer() {
    MapperScannerConfigurer msc = new MapperScannerConfigurer();
    msc.setBasePackage("com.ylf.dao");
    return msc;
  }
}

• jdbc.properties

jdbc.driver=com.mysql.jdbc.Driver
jdbc.url=jdbc:mysql://localhost:3306/db02
jdbc.name=root
jdbc.password=123

• SpringMvcConfig

package com.ylf.config;

import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.EnableWebMvc;

@Configuration
@ComponentScan("com.ylf.controller")
@EnableWebMvc
public class SpringMvcConfig {}

• ServletConfig

package com.ylf.config;

import org.springframework.web.servlet.support.AbstractAnnotationConfigDispatcherServletInitializer;

public class ServletConfig extends AbstractAnnotationConfigDispatcherServletInitializer {
  @Override
  protected Class<?>[] getRootConfigClasses() {
    return new Class[] {SpringConfig.class};
  }

  @Override
  protected Class<?>[] getServletConfigClasses() {
    return new Class[] {SpringMvcConfig.class};
  }

  @Override
  protected String[] getServletMappings() {
    return new String[] {"/"};
  }
}

3. 定义返回格式

• 在controller里创建Result类

package com.ylf.controller;

public class Result {
  private Object data;
  private Integer code;
  private String message;

  public Result() {}

  public Result(Integer code, Object data) {
    this.data = data;
    this.code = code;
  }

  public Result(Integer code, Object data, String message) {
    this.data = data;
    this.code = code;
    this.message = message;
  }

  public String getMessage() {
    return message;
  }

  public void setMessage(String message) {
    this.message = message;
  }

  public Object getData() {
    return data;
  }

  public void setData(Object data) {
    this.data = data;
  }

  public Integer getCode() {
    return code;
  }

  public void setCode(Integer code) {
    this.code = code;
  }
}

• 定义Code类型

package com.ylf.controller;

public class Code {
  public static final Integer SAVE_OK = 20011;
  public static final Integer DELETE_OK = 20021;
  public static final Integer UPDATE_OK = 20031;
  public static final Integer GET_OK = 20041;

  public static final Integer SAVE_ERR = 20010;
  public static final Integer DELETE_ERR = 20020;
  public static final Integer UPDATE_ERR = 20030;
  public static final Integer GET_ERR = 20040;
}

• controller

package com.ylf.controller;

import com.ylf.pojo.Student;
import com.ylf.service.StudentService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.*;

import java.util.List;

@RestController
@RequestMapping("/students")
public class StudentController {
  @Autowired private StudentService studentService;

  @PostMapping
  public Result save(@RequestBody Student student) {
    Boolean flag = studentService.save(student);
    return new Result(flag ? Code.SAVE_OK : Code.SAVE_ERR, flag);
  }

  @PutMapping
  public Result update(@RequestBody Student student) {
    Boolean flag = studentService.update(student);
    return new Result(flag ? Code.UPDATE_OK : Code.UPDATE_ERR, flag);
  }

  @DeleteMapping("/{id}")
  public Result delete(@PathVariable Integer id) {
    Boolean flag = studentService.delete(id);
    return new Result(flag ? Code.DELETE_OK : Code.DELETE_ERR, flag);
  }

  @GetMapping("/{id}")
  public Result findById(@PathVariable Integer id) {
    final Student student = studentService.findById(id);
    return new Result(
        student != null ? Code.GET_OK : Code.GET_ERR, student, student != null ? "请求成功" : "数据请求失败");
  }

  @GetMapping
  public Result findAll() {
    final List<Student> student = studentService.findAll();
    return new Result(
        student != null ? Code.GET_OK : Code.GET_ERR, student, student != null ? "请求成功" : "数据请求失败");
  }
}

四、异常处理

1. 在controller里创建ProjectExceptionAdvice类。声明这个类用来做异常处理

package com.ylf.controller;

import org.springframework.web.bind.annotation.ExceptionHandler;
import org.springframework.web.bind.annotation.RestControllerAdvice;

@RestControllerAdvice
public class ProjectExceptionAdvice {
  // 统一处理所有异常
  @ExceptionHandler(Exception.class)
  public Result doException(Exception ex) {
    return new Result(500, null, "发生异常");
  }
}

记得加包扫描。@SpringBootApplication和ComponentScan一起用的话ComponentScan会覆盖掉SpringBootApplication

@ComponentScan("com.ylf.controller")

2. 创建自定义异常类
   BusinessException

package com.ylf.exception;

public class BusinessException extends RuntimeException {
  private Integer code;

  public Integer getCode() {
    return code;
  }

  public void setCode(Integer code) {
    this.code = code;
  }

  public BusinessException(String message, Integer code) {
    super(message);
    this.code = code;
  }

  public BusinessException(String message, Throwable cause, Integer code) {
    super(message, cause);
    this.code = code;
  }
}

SystemException

package com.ylf.exception;

public class SystemException extends RuntimeException {
  private Integer code;

  public Integer getCode() {
    return code;
  }

  public void setCode(Integer code) {
    this.code = code;
  }

  public SystemException(String message, Integer code) {
    super(message);
    this.code = code;
  }

  public SystemException(String message, Throwable cause, Integer code) {
    super(message, cause);
    this.code = code;
  }
}

3. 定义code异常类型

package com.ylf.controller;
public class Code {

  public static final Integer SYSTEM_ERR = 50001;
  public static final Integer BUSINESS_ERR = 50002;
  public static final Integer SYSTEM_UNKNOWN_ERR = 50003;
}

4. 在controller里可能会出现异常的地方抛出自定义异常

  @GetMapping("/{id}")
  public Result findById(@PathVariable Integer id) {
    try {
      int i = 1 / 0;
    } catch (Exception e) {
      throw new BusinessException("出现异常", e, Code.BUSINESS_ERR);
    }
    final Student student = studentService.findById(id);
    return new Result(
        student != null ? Code.GET_OK : Code.GET_ERR, student, student != null ? "请求成功" : "数据请求失败");
  }

5. 拦截并处理异常

package com.ylf.controller;

import com.ylf.exception.BusinessException;
import com.ylf.exception.SystemException;
import org.springframework.web.bind.annotation.ExceptionHandler;
import org.springframework.web.bind.annotation.RestControllerAdvice;

@RestControllerAdvice
public class ProjectExceptionAdvice {
  @ExceptionHandler(Exception.class)
  public Result doException(Exception ex) {
    // 1. 记录日志
    // 2. 发送ex对象邮件给开发人员
    return new Result(Code.SYSTEM_UNKNOWN_ERR, null, "系统繁忙");
  }

  @ExceptionHandler(SystemException.class)
  public Result doSystemException(SystemException ex) {
    // 1. 记录日志
    // 2. 发送ex对象邮件给开发人员
    return new Result(ex.getCode(), null, ex.getMessage());
  }

  @ExceptionHandler(BusinessException.class)
  public Result doBusinessException(BusinessException ex) {
    return new Result(ex.getCode(), null, ex.getMessage());
  }
}