在vue中实现PDF文件流预览功能

<template>
	<div class="print">
		<div v-if="!viewShow" class="opt-box">
			<div style="height: 700px; overflow: auto;">
				<el-table :data="tableData" border>
					<el-table-column prop="no" label="序号" align="center">
					</el-table-column>
					<el-table-column prop="proveTypeName" label="文件名称" align="center">
					</el-table-column>
					<el-table-column prop="applyTime" label="申请时间" align="center">
					</el-table-column>
					<el-table-column label="操作" width="260" align="center">
						<template slot-scope="scope">
							<el-button type="text" icon="el-icon-view" @click="onChangeView(scope.row)"> 查看 </el-button>
						</template>
					</el-table-column>
				</el-table>
			</div>
		</div>
 
		<input ref="input" style="width: 100px" v-show="false" type="file" />
		<div class="print-btn" v-if="viewShow">
			<div class="txt-btn">今日已打印 {{dayCount}} 次 </div>
			<el-button circle type="primary" @click.stop="printAssignFile">打印文件</el-button>
			<el-button circle @click="clearBox">返回上级</el-button>
		</div>
		<div v-show='viewShow' id="viewBox">
		</div>
	</div>
</template>
 
<script>
	import { printFile, getPrintList } from "@/api/print";
	import { provePreview, queryPrintsSum } from "@/api/preview";
 
	const blobToJson = (data) => {
		return new Promise((resolve, reject) => {
			const reader = new FileReader();
			reader.readAsText(new Blob([data], {
				type: 'application/json'
			}), 'utf-8');
			reader.onload = () => {
				try {
					const json = JSON.parse(reader.result);
					resolve(json);
				} catch (e) {
					reject(e);
				}
			};
		});
	}
	export default {
		data() {
			return {
				tableData: [],
				dayCount: '',
				viewShow: false,
				dataFile: {},
				proveId: '',
			};
		},
		mounted(){
            //获取列表数据
			this.init();
			//获取打印次数
			this.getPrintsSum()
		},
		methods: {
			//获取列表数据
			init() {
				getPrintList(this.page).then((res) => {
					if (res && res.code === 200) {
						this.tableData = res.data.recordList;
					} else {
						this.$message.error(res.msg);
					}
				});
			},
			//获取打印次数
			getPrintsSum(){
				queryPrintsSum().then((res)=>{
					if(res && res.code == 200){
						this.dayCount = res.data
					} else {
						this.$message.error(res.msg);
					}
				})
			},
			// 清除pdf
			clearBox() {
				this.viewShow = false
				var e = document.querySelector("#viewBox");
				var child = e.lastElementChild;
				while (child) {
					e.removeChild(child);
					child = e.lastElementChild;
				}
			},
            // 展示PDF文件的预览
			showPdfPreview(data) {
				let _self = this
				const deal = () => {
					try {
						_self.clearBox()
						const viewBox = document.getElementById('viewBox');
						const pdf = document.createElement('iframe')
						pdf.id = 'iframe'
						pdf.setAttribute('frameborder', 0)
						const blob = new Blob([data], {
							type: 'application/pdf'
						});
						const pdfUrl = URL.createObjectURL(blob);
						pdf.src = pdfUrl + '#toolbar=0';
						pdf.style.width = '100%'
						pdf.style.height = '100%'
						viewBox.appendChild(pdf)
						_self.viewShow = true
					} catch (e) {
						_self.$message.error("未能正确加载文件");
						_self.clearBox()
					}
				}
				//1. 先将数据转换成json，看下是否是异常
				try {
					blobToJson(data).then((json) => {
						_self.$message.error(json.msg || "未能正确加载文件");
						_self.clearBox()
					}).catch((e) => {
						deal()
					})
				} catch (e) {
					_self.$message.error("未能正确加载文件");
					_self.clearBox()
				}
			},
			//预览
			onChangeView(row) {
				this.dataFile = row
				provePreview({
					proveId: row.proveId
				}).then((res) => {
					this.showPdfPreview(res)
					//获取打印次数
					this.getPrintsSum()
					if (res.code == 500) {
						this.$message.error("文件加载异常" || res.msg);
					}
				}).catch(err => {
					this.clearBox()
					this.$message.error("未能正确加载文件");
				});
			},
			//文件打印
			printAssignFile() {
				printFile(this.dataFile).then((res) => {
					if (res.code === 200) {
						//获取打印次数
						this.getPrintsSum()
						this.$message.success(res.msg);
					} else {
						this.$message.warning(res.msg);
					}
				});
			},
		},
	};
</script>
<style lang='less' scoped>
	.print {
		width: 100%;
		height: 100%;
		margin-top: 200px;
	}
	#viewBox {
		width: 70%;
		height: 720px;
		background-color: #ccc;
		margin: 0 auto;
	}
	.print-btn {
		position: fixed;
		top: 180px;
		right: 60px;
		display: flex;
		flex-direction: column;
		align-items: center;
 
		.txt-btn {
			margin-bottom: 30px;
			display: block;
			font-size: 22px;
			font-weight: 500;
			color: black;
			width: 180px;
			text-align: center;
		}
		.el-button {
			width: 160px;
			height: 160px;
			font-size: 22px;
		}
		.el-button+.el-button {
			margin-top: 30px;
			margin-left: 0 !important;
		}
	}
</style>

/**
 * 证明预览
 * @param {*} data pdf文件流
 * @returns
 */
export function provePreview(data) {
	return request({
		url: "/layout/api/view",
		method: "post",
		data: data,
		responseType: 'blob',	//一定要设置响应类型，否则页面会是空白pdf
		contentType: "application/json;charset=UTF-8"
	});
}