标签：dto String private json split 字符串 import com fileOutputStream

package com.itheima.controller;

import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.itheima.entity.Book;
import com.itheima.entity.JsonEntity;
import com.itheima.entity.SelectParams;
import com.itheima.mapper.BookMapper;
import com.itheima.test.JdbcConfig;
import lombok.RequiredArgsConstructor;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;

import javax.sql.DataSource;
import java.io.*;
import java.util.ArrayList;
import java.util.List;

@RestController
@RequiredArgsConstructor
public class HelloController {
    private final ObjectMapper objectMapper;
    private final BookMapper bookMapper;
    private final DataSource dataSource;
    private final JdbcConfig jdbcConfig;
    private final Book book;
    private final SelectParams selectParams;

    @GetMapping("hello")
    public List<Book> hello() {
        //将从数据库中查询的数据做成一个文件
        selectParams.setAuthorStr("佚名");
        selectParams.setGetCreateDateFrom("20210312");
        //List<Book> bookList = bookMapper.selectAllBook();
        List<Book> bookList = bookMapper.selectBookByParam(selectParams, 1200);
        FileOutputStream fileOutputStream = null;
        try {
            fileOutputStream = new FileOutputStream("E:\\temp.txt");
            /** ObjectOutputStream objectOutputStream = new ObjectOutputStream(fileOutputStream);
             for (Book book:
             bookList) {
             objectOutputStream.writeObject(book);
             }*/
            for (Book book :
                    bookList) {
                fileOutputStream.write(String.valueOf(book.getId()).getBytes());
                System.out.println(String.valueOf(book.getId()).getBytes());
                fileOutputStream.write("\t".getBytes());
                fileOutputStream.write(book.getBookName().getBytes());
                fileOutputStream.write("\t".getBytes());
                fileOutputStream.write(book.getAuthor().getBytes());
                fileOutputStream.write("\r\n".getBytes());
            }
        } catch (IOException ioException) {
            ioException.printStackTrace();
        } finally {
            try {
                fileOutputStream.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }

        //从作成的文件中读取数据到实体pojo类中
        FileInputStream fileInputStream = null;
        try {
            fileInputStream = new FileInputStream("E:\\temp.txt");
            int len = 0;
/**           while ((len=fileInputStream.read())!=-1){
 System.out.println(len);
 }*/
            byte[] bytes = new byte[1024];
            while ((len = fileInputStream.read(bytes)) != -1) {
                //System.out.println(new String(bytes,0,len));
                String pojoTemp = new String(bytes, 0, len);
                String[] split = pojoTemp.split("/t");
/**                System.out.println("-----------以换行符分割----------");
 for (int i = 0; i < split.length; i++) {
 System.out.println(split[i]);
 }*/
                System.out.println(split[0]);
            }
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            try {
                fileInputStream.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        List<Book> bookListJson = new ArrayList<>();
        return bookList;
    }

    @GetMapping("jsonConvert")
    public void convertJsonToEntity() {
        StringBuilder paramStringBuilder = new StringBuilder();

        // 获取request参数
        String requestJson = "param01=12,param02=13,param03=14,paramList=[12,13,14],param04=15,param05=16,param06=17";

        // “=”置换为“:”
        String replaceRequestJson = requestJson.replace("=", ":");
        paramStringBuilder.append(replaceRequestJson);

        // list取出并删除
        int paramListIndexFrom = paramStringBuilder.indexOf("paramList");
        int paramListIndexTo = paramStringBuilder.indexOf("]");
        String[] paramListStr = paramStringBuilder.substring(paramListIndexFrom, paramListIndexTo+1).split(":");
        String paramListKey = paramListStr[0];
        String paramListValue = paramListStr[1];
        StringBuilder stringBuilderConvert = new StringBuilder();
        stringBuilderConvert.append("{");
        stringBuilderConvert.append("\"" + paramListKey + "\"" + ":"  + paramListValue);
        stringBuilderConvert.append(",");
        paramStringBuilder.delete(paramListIndexFrom, paramListIndexTo + 2);

        String[] split = paramStringBuilder.toString().split(",");
        int a = split.length;

        int add = 0;
        for (String item :
                split) {
            String[] splitTemp = item.split(":");
            String key = splitTemp[0];
            String value = splitTemp[1];
            stringBuilderConvert.append("\"" + key + "\"" + ":" + "\"" + value + "\"");
            add++;
            if (add != split.length)
            {
                stringBuilderConvert.append(",");
            }
        }
        stringBuilderConvert.append("}");
/*


        String json = "{\n" +
                "  \"param01\": \"1\",\n" +
                "  \"param02\": \"www.runoob.com\",\n" +
                "  \"param03\": \"1\",\n" +
                "  \"param04\": \"菜鸟教程\",\n" +
                "  \"param05\": \"www.runoob.com\",\n" +
                "  \"param06\": \"1\",\n" +
                "  \"paramList\": [\n" +
                "    1,\n" +
                "    2,\n" +
                "    3,\n" +
                "    4\n" +
                "  ]\n" +
                "}";*/

        System.out.println(stringBuilderConvert.toString());
        try {
            JsonEntity jsonEntity = objectMapper.readValue(stringBuilderConvert.toString(), JsonEntity.class);
            System.out.println(jsonEntity);
        } catch (JsonProcessingException e) {
            e.printStackTrace();
        }
    }
}

package com.itheima.entity;

import lombok.Builder;
import lombok.Data;
import lombok.RequiredArgsConstructor;
import org.jetbrains.annotations.NotNull;

import java.util.List;

@RequiredArgsConstructor
@Builder
@Data
public class JsonEntity {
    @NotNull
    private String param01;
    @NotNull
    private String param02;
    @NotNull
    private String param03;
    @NotNull
    private String param04;
    @NotNull
    private String param05;
    @NotNull
    private String param06;
    @NotNull
    private List<String> paramList;
}

标签：dto,String,private,json,split,字符串,import,com,fileOutputStream
来源： https://blog.csdn.net/qq_41006598/article/details/120232915

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